Super Insulated houses in Issue 194
All
What did you guys think of this article.
Rich
Houses you can heat with a hair dryer
The cold weather in Urbana, lll., barely registered inside the superinsulated houses on display at the second-annual North American Passive House Conference hosted by the Passive House Institute (www.passivehouse.us) and the Ecological Construction Laboratory (www.e-colab.org). The homes incorporate superinsulation details initially developed in Germany and use about 10% of the heating energy of a conventionally built home.
Designed by Katrin Klingenberg of e-co lab, these 1200- to 1300-sq.-ft. houses share a similar construction and design approach: a compact form with a superinsulated envelope, superior airtightness, wholehouse heat-recovery ventilation, and passive-solar gain. The houses also share something even more unusual: They don’t have conventional heating systems. Because superinsulation strategies are employed, the heating requirement is incredibly low. The total peak heating load for each house is about 6600 Btu/hour. Typical homes built to meet the 2006 International Energy Conservation Code would use about 38,000 Btu/hour, or six times as much.
Carbon neutrality within reach today
Conference organizers maintain that passive-house construction (residential and commercial, new and retrofit) is economically viable and capable of addressing the energy challenges of today, such as the architecture2030 challenge put forth by architect Ed Mazria (www.architecture2030.org).
Presentations ranged from case studies of passive houses and other ultralow-energy buildings to lectures about building science, metrics, and the philosophy of environmentally responsive design.
Small-group interactive sessions on the second day allowed those present to discuss and debate various issues, such as the current role of architects (help or hindrance?) in low-energy construction. Many attendees were as knowledgeable as the presenters, and conversation flowed from the early morning until late in the evening.
Somewhere along the way, an avant-garde marketing idea for passive houses emerged: “Hot babe heats house.†Technically speaking, though, it would need to be a hot babe with an electric hair dryer.
Replies
The numbers are ballpark ok for that size house. I remember sitting through an evening course back in the early 80s, given by Gene Leger, on superinsulated houses. He spoke of designing improvements into various parts of a proposed house until he got to the point where the heat losses in the dead of winter were less than the "free" heat (normal utility use - TV, stove, lights, etc. and solar gain) used anyway. At that point, the conventional heating system disappeared.
That 6600 BTU/hr is 1.93 KW of electrical power, part of which is that "free" use. A TV uses a bunch, lights more. Even if no appliances were on for a while, that 1.93 KW is about a hair dryer and a half. For a 1200 watt dryer, the house could be heated down to the low 20s outside temperature.
Dick
Thanks for the reply.
I've got Bible study tonight so I can't post for long.
I was intrigued by the use of I joists to frame the walls.
Why couldn't a guy frame the walls with I joists and blow them with Cellulose.
Might be more acceptable to the mainsteam than the Larsen Truss system or the Mooney wall for speed of framing.
Rich
good idea.... wonder why they switched from I-joists to sips ?Mike Smith Rhode Island : Design / Build / Repair / Restore
Mike
View ImageSuperinsulated walls are as thick as floors. Built in a warehouse, the R-60 walls are framed with I-joists, insulated with blown-in fiberglass, and skinned on both sides with oriented strand board. They’re then delivered to the job site and hoisted in place with a crane.
I think they are using I joists. I just now read they are blown with fiberglass. when I read the magazine i thought they were built with foam. It's amzing how you can read something and read your assumptions into it.
Rich
Here's a link to a builder who uses something like a cross between an I-joist and Larsen truss. It has a 12" cavity, low thermal bridging, cellulose fill. He claims R45 wall, R100+ attic. Some photos of the framing and pre-made wall joists stacked and ready for assembly. I came across this last spring, while searching on the subject.http://www.dcchomes.com/On the matter of inside vapor barrier, here's a reference to something good on that, from a post over on JLC some time back:http://www.balancedsolutions.com/website/downloads/ASHRAE_Thermal8_Vapor_Barriers.pdfIt's by John Straube. He shows that, in absolute terms, a 1-perm vapor retarder inside lets so little water vapor through the wall into the cavity, in winter in Omaha, that even if it's all absorbed by the studs and sheathing the percent moisture over three months remains within the normal moisture range of wood products. Cellulose will do this also. Later the moisture is released as the wall warms. The moisture should be able to dry slowly to the inside.Bottom line: inside vapor barriers (poly) aren't a good idea in most heating climates. A 1-perm vapor retarder is all that is needed, and the natural moisture buffering capabilities of the wall materials can be used to advantage, as long as the wall can dry out later.
Edited 3/19/2008 9:25 am ET by DickRussell
nice site , dick... thanksMike Smith Rhode Island : Design / Build / Repair / Restore
Had a look at the DCC pages. How is he blowing cellulose into walls with vapour barrier on them? I thought you had to have sometype of permeable covering (like the insulmesh) on the walls to let the blower air out? Wouldn't they just blow up like a ballon?
A.
Dick
Thanks for the link.
Lots of good reading.
I'm not sure I understood the vapor barrier article. I'll have to go back thru it when I am more awake.
Rich
rich ... do any of those links show the details ?
like the foundation, the windows, doors & the attic ... i can see the R-60 walls ... nothing but sips.... what about the rest ?
Mike
All the links work, but not too many details.
Gotta go .
Rich
Pardon me for butting in, but this article has a bit more detail. The framing is interesting. http://www.e-colab.org/ecolab/ecolabHome_files/EDU%20May2007%20Postable.PDF
thanks ....... good info on the specs .. looks like it was from a 2d generation passivhaus
cargin's article must be from a 3d or 4th generation
really would like to know what the windows were in "cargin's house "
the rest of it i can figure outMike Smith Rhode Island : Design / Build / Repair / Restore
Jim
Thanks for that link.
That was good reading.
Gets the mind to thinking.
Rich
Haven't read the article - only what you've posted.
My reaction: ugly houses made with all synthetic materials and lots of embodied energy.
Isn't it about time we think about SUSTAINABLE building and not simply energy-efficiency - and only operating energy efficiency at that.
Solar & Super-Insulated Healthy Homes
Robert
Haven't read the article - only what you've posted.
That was the article. Thta was it.
Ever heard of that group?
I was wondering what you thought about living in a house with the off gassing of the OSB.
Rich
Ever heard of that group?
No, but the Energy Design Update article mentions:
"Duncan Prahl, the research manager at Integrated Building And Construction Solutions (IBACOS) in Pittsburgh, Pennsylvania, is now monitoring the energy performance of the second Urbana Passivhaus."
Duncan Prahl used to run the Energy-Crafted Home program for MA utilities and was my consultant when I built a modified Larsen Truss duplex under his program.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Riversong,
I've been enjoying your posts since you've come on board here. You've got a wealth of knowledge, and your willingness to take part in so many of the discussions is much appreciated.
I, too, wonder about the embodied energy, the lack of aesthetics and the proponderance of synthetic materials. As I consider the "embodied energy" of my own home -- especially if prorated since its construction in the 1830s (with minimal alterations) --I'd venture that it's very low. And most of that energy was in the form of water-power (saws), human toil and animal labor.
Wood was burned to make the lime (for the foundation mortar and interior plaster), and to make the window panes.
Over the years, probably a couple hundred gallons of paint, and several generations of roofing had to be manufactured, transported and installed.
Do you know of any formula or quantitative measuring system for determining "embodied energy"?
In the end though, I'm sitting here with coat and hat on in order to NOT burn oil. By contrast, in the homes shown in the article, my computer alone would probably be enough to keep a room comfortable. When it's below 25 degrees outside, I break down and run the furnace so the pipes don't freeze. So we've burned several hundred gallons of oil this season, alone.
The inefficiencies of the house likely have far outweighed the "low embodiment" factors. But, for me, the aesthetic factors (natural materials, historic character, etc.,) still tip the scales in my home's favor!
Allen
The inefficiencies of the house likely have far outweighed the "low embodiment" factors.
Renovating an old house to improve efficiency is certainly a more ecological route than building new (unless, perhaps, one builds with all recycled materials).
But there doesn't have to be a trade-off between sustainable, low-embodied materials and high efficiency and livability. We just need to learn how to make the most appropriate choices and be willing to invest the effort to build so that future generations might have some choices.
Net zero energy is a chimera. 14" of XPS under the slab? Carcinogenic fiberglass blown into the walls? OSB throughout? Natural ACH of 0.01 making the house so tight that if the power goes out to the HRV then the occupants die in their sleep?
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/18/2008 8:09 pm ET by Riversong
Riversong,
You've got some good ideas, but you often give in to your irresistable urge to exaggerate.
"Carcinogenic fiberglass blown into the walls? ... Natural ACH of 0.01 making the house so tight that if the power goes out to the HRV then the occupants die in their sleep?"
Because of global climate change, we need innovative solutions that allow us all to make the transition to a low-carbon future. The Passivhaus builders are actively working on those solutions. If you remain so rigid as to think that only your Vermont designs are acceptable -- I'm speaking as a rural resident of northern Vermont -- many readers will conclude that you are simply arrogant and tune you out.
I suggest you develop your tolerance somewhat.
I suggest you develop your tolerance somewhat.
ditto
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Riversong,
Fair enough. What evidence do you have that fiberglass insulation, installed behind drywall, is carcinogenic? Have you ever heard of anyone who has died in a house due to a power outage that disabled an HRV? (Carbon monoxide poisoning due to a gas-powered generator in the garage doesn't count.)
Edited 3/19/2008 12:34 pm ET by MartinHolladay
Read my posts on OSB and EPS.
The health impacts - both physiological and environmental - are not limited to end use, but occur more often at the front and back ends of the life cycles of materials.
Sure, I was being hyperbolic about "dying in the night" to make a point. But building hermetically-sealed homes which are livable only with "artificial respiration" is so antithetical to the way nature works and we evolved as living creatures as to be absurd. I was atttempting to highlight the absurdity.
Hikers might also be happy with rubber raincoats if they had battery-powered ventilation systems (at least until the batteries died).
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/19/2008 8:36 pm ET by Riversong
ACH of 0.01
Scary. That's 100 hours for one air change.
Isn't a refrigerator seal like 0.1 or so?Occupational hazard of my occupation not being around (sorry Bubba)
ACH of 0.01
Scary. That's 100 hours for one air change.
Isn't a refrigerator seal like 0.1 or so?
That's my point. Who would want to live in a fridge?
The first "stress-skin panel" houses were made from gasketted foam-core steel panels recycled from walk-in coolers.
It seems we've only perfected the ridiculous.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
That's my point. Who would want to live in a fridge?
Yeah, but all the "literature" tells us We Must Live Airtight! Which is the problem with having only one "book" to read from.
Helped build some "fridges" down around Lake Conroe in the early 80's. Massive walls (2x6 with 2" of isoboard outside), then brand-new 14" TJI ceiling joists fully filled with insulation, metal roofs on skip sheathing "flying" over the sealed-up ceiling decks. Even had solar collectors for hot water. Should have been nirvana, right? Nope, electrical use was about the same as "ordinary" construction. Lights and ventilation negated much of the savings. That, and still needing a decent-sized a/c plant to dehumidify the air the occupants were constantly trying to freshen.
Win some, lose some. Cruel calculus on those, you had to size duct work for air changes, not cooling loads; but it was hard to get a blower unit big enough to fit 1/2 & 3/4 ton a/c units for 2800-3200sf. Shoulda-woulda-coulda just built "Texas Victorians" with sensible materials. At least none of the solar water heaters are out of commission but two; one was owner-demolished, the other lost in a fire.Occupational hazard of my occupation not being around (sorry Bubba)
capn..
in the early '80's one of my BIL's was managing the marina at Lake Conroe ( after a Navy hitch and knocking around Newport )stayed with it until the oil patch collapsethe boat owners would come in ... throw their keys on the desk... and tell him to give them to the bank
he was one of the last to leavehe's still in the Conroe area... currently teaching HS historyMike Smith Rhode Island : Design / Build / Repair / Restore
he's still in the Conroe area
Conroe is still there, it's struck a balance. Had to. After the Patch drained out, then there was a drought, and the lake almost emptied. Then there were some record floods after that (which confused all the folks who fled Houston, and had never seen the lake full, let alone flooding).
Conroe now abuts Montgomery, and is butting up hard against Spring--it's getting tough to see where metro Houston/Harris County ends and Montgomery County begins anymore.Occupational hazard of my occupation not being around (sorry Bubba)
Capn Mac
The article in this link mentions .25 air changes /hour at 50 psi (blower door test) on page 3.
I don't know where the .01 was mentioned.
I don't know if we are talking apples to apples here.
http://www.e-colab.org/ecolab/ecolabHome_files/EDU%20May2007%20Postable.PDF
Rich
The article in this link mentions .25 air changes /hour at 50 psi (blower door test) on page 3. I don't know where the .01 was mentioned.
0.25 ACH at 50 pascals, which equates (according to the article) to 0.01 natural ACH.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Robert
I saw it this time in Table 1.
What is considered a healthy ACH?
What do your houses do?
I believe you run bathroom fans to increase the ACH.
I would do a search and read up on that, but alas the posts are deleted. Atempting to LOL.
I think shelter nerd also mentioned something about running bathroom fans, but I could be wrong. Have been before.
Rich
Edited 3/21/2008 8:14 am ET by cargin
I believe you run bathroom fans to increase the ACH.
Which only works if a window or door is open. And while the fan runs.
If a door or window is open, you are letting in untempered air (which could have a 30-60 or more DeltaT) which negates the superinsulation.
Or the "draw" works on any existing tiny air leakage trying, as Nature always does, to balance things out, and leak more.Occupational hazard of my occupation not being around (sorry Bubba)
CapnMac
Thank you.
So what's a guy to do?
Die of stale air or heat the outdoors.
I know a balance.
Maybe one should install a baffled (or controlled intake) and a baffled chimney effect type outlet. And only use the HRV when it is very cold.
Rich
Edited 3/21/2008 11:02 am ET by cargin
Maybe one should install a baffled (or controlled intake) and a baffled chimney effect type outlet.
Well, that is the definition of an HRV (heat recovery ventilator).
Does kind of defeat the purpose of superinsulating if you let cold air in the house (even at measured rates), though. Controled intake probably better than non-controlled, naturally. But, perhaps a 2x4 "mooney" wall or a PERSIST wall would be much simpler than the TJI walls used, too.Occupational hazard of my occupation not being around (sorry Bubba)
hah... thought you could sneak that "PERSIST " wall by me , huh ?
all, right... what 's a PERSIST wall ?Mike Smith Rhode Island : Design / Build / Repair / Restore
PERSIST is when the exterior walls have a membrane, usually of the peel and stick variety like Grace, on the exterior side of the shell. ie, vapor retarder on the exterior, not interior.
I'm not positive what it stands for...
Pressure
Equalized
Rain
Screen
Insulating
S ??
T ??
thought you could sneak that "PERSIST " wall by me , huh ?
No sir, I presume that your attention to detail is, as ever, perennial sharp.
(That, I've clean forgot what "we're" supposed to call your and Mooney's wall <g>)
Ok, and the fact that, if I do it, I want the foam & strapping on the "wrong" side--which winds up looking more like PERSIST (or whatever Ray Moore is Acronyming it now--dang it, CRS hitting hard today).Occupational hazard of my occupation not being around (sorry Bubba)
So Mike,
Which, if any, of these walls would you like to encorporate in a new home?
Do you see anything that compares with the Mooney wall for simplicity, economy of materials, and/or energy efficiency?
These super efficient designs make me wonder if you've ever built a Mooney wall using 2X6 on 24" centers?
Theoretically, according to data you've posted, that combination would bring the R value up to about 27, wouldn't it?
you're just sidling for the evolved wall to be a Mooney-Hudson Wall , ain't cha ?for that matter..... and now that you got me thinking.... sure but why stop at 2x6 ?
why not 2x8 with 2x2 Mooney
10% of the wall would be 2x......9 @ R-9
& 90% of the wall would be cells @ R-33
for a net of say R-30the benefits.... you can still do tilt-up
the Mooney supplies a 1.5" interior plane that you can glue Insulweb to and provide a blocking plane for anything you needthe header areas will become better insulated ( even though we're using insulated box beams wherever code allows .... usually up to 8')you can single plate it or use a rimboard... the ply sheathing will still tie past it
you can use a rimboard for a shoe .... or a 2x4 for a shoe... the Mooney will cover the gap at the bottomtruth be told...... you have a good idea... i'd still frame it 16" on center for a better exterior plane and also... it would facilitate stacking the rafters..... if you are going to truss the roof ( which we PROBABLY would --- we want a big energy heel )... then i'd go 24" OC .... again so we can stack the rafters my BI would allow me to span the area from 16" below the plate to the top of the energy heel so my Windload tie-down would be in effecti have some ideas for the foundation...... if you want to go slab-on -grade and RFH... no... scratch the RFH well...... maybe a limited RFH since the heat loss is going to be so minimal...... my heat source in that case would probably be in the neighborhood of a 20 gal Elec. water heater... i'm thinking edge loss of say R-20 or R-30 ( 6" EPS borate treated ) and the same for the slab.... i can get EPS in 2 lb/cf density for under slabsor maybe ... since it would not be calling much ...i'd use an instantaneous HW heater...
one for RFH and a separate one for DHWAC would be one or two $100 window units in a custom thru -wall sleeveattic would be our usual R-60which brings us right back to the olde achilles heel..... windows & doorsdoors would be only hinged... no sliders.... we could use a center -hinged 6' if we want some big glass to the south..... with a storm panel over the fixed side & a storm door , fll view over the hinged sideother door/doors would be steel insulated with storm doorsand windows...... what to do for windows ? first... most would have to operate... some COULD be fixed
casements are most energy efficient..... but tend to the ugly side in some types of architecture... and they tend to have more issues long termi think i'm inclined to go with an Andersen 400, lo-e........ and a full exterior storm panel that mounts over the casingbut i'm not married to the windows... nor anything else in this quest
so whadda ya think.....☂ will it rain on our parade ?Mike Smith Rhode Island : Design / Build / Repair / Restore
Mike
I like the 2X8 concept fine but...how about something like Jon B. suggested earlier, when I went off on that 2X4 on edge tangent...a second 2X4 interior wall?
Allowing a small space between the outer and inner walls would eliminate bridging and the need to rip all that 2X and apply it. Probably work out to be about the same labor to frame and raise the second wall as doing the 2X2. And 2X4 is less per bd.ft. than 2X8 so there'd be some savings.
Of course, this may not work like I'm thinking. You're the Mooney inventor/collaborater so I'm just tossing out stuff that comes to mind, seeing if any of it fits with your experience.
Windows....someone in this thread had a source for superior quality triple insulated glass. I'll probably look into that.
Building in the country on view lots means that I'm going to have big areas of glass in several rooms. Square feet can be controlled but I'd rather control heat loss by other means.
I worked with glaziers once on a union job at West Point. They told me that glass is very cheap. Since then I've ordered several custom size double panes from glass shops. They were factory made and very reasonably priced.
That has led me to consider building my own fixed frames for large openings and ordering triple insulated glass for them. I'd just pick a casement unit I liked and match my fixed opening to it for height.
The only idea that's come to me about big fixed glass is to make up an insulated shutter to fit over it at night. With big roof overhangs I can envision overhead shutters on hinges, suspended from the soffit during daylight hours.
Making the shutter up similar to an SIP but lighter could be an answer to heat loss. With a flexible gasket and a little pressure, it would seal pretty well too.
In any case, it's pretty easy to experiment with some foam pressed against a window, see how it effect the interior temperature of the glass.
I'll continue your tangent.The reason I mentioned the double 2x4 wall is for the same reasons you're bringing it up. I once was thinking about utilizing the mooney wall concept but in such a way to compete with a SIP's or other super insulated shells. A 2x4 mooney is probably better than 98% of the existing walls out there, but still it can't compete with an 8" SIP wall.I recently got a quote on a 4-5/8" SIP wall from R control. The material price, not including dimensional lumber, was around $13k. This was for ~350LF of 9' exterior wall. I did a breakdown and realized that a conventional wood frame with 1" of closed cell foam sprayed in would still be a good bit cheaper. We actually went with 2x4's 16" OC, double top plates, blown in cells, and 1" EPS on the exterior. I don't think that wall's performance will rival the 4-5/8" SIP, but our blower door test week after next will give me something measurable.Still, I have wondered how much extra an 8" of 10" SIP wall would have been. I would have lost interior SF (and been taxed on the extra thick wall as you mentioned) but I'm guessing that the incremental cost for extra foam would be pretty minimal. Installation would basically be the same as a 4-5/8" wall, which is not something that can be said for the Mooney or double 2x4 wall.So, I'm wondering where the break even point with stick framing vs. other wall sections is. If you wanted a 24" thick R90 wall, SIP would seem to be the way to go. But I bet we could have done a 2x4 mooney for less than the 4-5/8" SIP wall.Decisions, decisions, decisions.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
Jon,
I ran numbers, couple days ago, for a 2x4 16"centers Mooney wall, 1/2" structural OSB w/Tyvek. With generous allowances for headers, jacks, and nails, including 15% for waste, materials came out to $1.76/sq ft.
That's includes $.52 sq.ft. per Mike Smith for all Mooney wall materials. Also per Mike, that wall would be ~ R-20.
Edited 3/22/2008 1:31 pm by Hudson Valley Carpenter
So I'm guessing that if you were to do a double 2x4 wall instead of the mooney you would be around $2.25? I guess the most logical way would be to frame the inside double wall just like an interior wall with 2x flat headers, minimal studs at the corners, etc.Just curious, is your $.52/SF number with 2x4's ripped in half?
Jon Blakemore RappahannockINC.com Fredericksburg, VA
So I'm guessing that if you were to do a double 2x4 wall instead of the mooney you would be around $2.25? I guess the most logical way would be to frame the inside double wall just like an interior wall with 2x flat headers, minimal studs at the corners, etc.
That's gotta be close on the materials. Yes on the framing description too...just enough for nailing.
Just curious, is your $.52/SF number with 2x4's ripped in half?
Here's Mike's post which details costs for the Mooney wall.
102263.36
Thanks for the link. I didn't realize the $.52/SF was for insulmesh and cellulose as well.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
The doubled 2X4 wall might turn out to be more like $2.50/sqft, with the added cellulose but that ain't too bad, considering all the benefits.
On the subject of taxes; given the "green" approach to building which is becoming a hot political issue, it seems likely that a revision of the appraisal rules to reflect actual living area could be lobbied for and brought to a vote in whatever government legislative body is responsible for that.
Can't very well promote green building while defeating one aspect of the incentive to do it.
Edited 3/22/2008 6:51 pm by Hudson Valley Carpenter
Mike,I know you've used SIPS before (in a basement I think), I'm not sure if you've done a whole house with them.My question for you is why would you consider a 2x8 mooney? Your wall section would be 8-3/4" thick, which is pretty substantial. The labor costs would not be much more than a 2x4 mooney but the material costs would likely double.I know the Mooney is good for having blocking where you need it, but wouldn't the SIP be just the same? Or at least almost as good?I guess I'm working off of the assumption that the incremental cost of increasing the foam in an SIP wall is not that significant. Maybe that's a poor assumption. I'm pretty sure that the labor cost would stay relatively constant.On a side note, have you done a blower door test on a hose with the Mooney wall? I would be curious to see what your infiltration rate is. I would expect it to be pretty low with the DP cells and expanding foam in the critical areas.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
CapnMac
or a PERSIST wall would be much simpler than the TJI walls used, too.
Yeah. What Mike said. Fess up. What is a PERSIST wall?
With pics, and documentation. LOL
Rich
Edited 3/21/2008 1:56 pm ET by cargin
What is a PERSIST wall?
Pressure Equalized Rain Screen Insulated Structure Technique.
Simlar to a REMOTE wall: Residential Exterior Membrane Outside Insulation Technique.
http://www.cchrc.org/Reports/REMOTE%208-2-06.pdf
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/21/2008 3:24 pm ET by Riversong
Robert
Thanks for the information.
This is a fun thread. Lots of good discussion.
Rich
Yeah. What Mike said. Fess up. What is a PERSIST wall?
"Presure Equalized Rain Screen Insulated Structure Techique"
Basic premise is to move the insulation (and VB) plane out of the structural plane entire. Since you are eliminating bridging almost entirely, you get a higher "assembly" R value for less insulating material. You also gain in that you are moving the structure inside the conditioned envelope of the building--which eliminates many worries about moisture problems affecting the framing.
If a person, for instance, uses SIPS over a timber frame--that's a form of the answer.
The impetus for this was in being able to build in extreme climates (Alaska, the Yukon, & such) where reducing the amount of insulation brought to a project was a net good (not having to truck more volume to extreme distances will do that).
I want to remember that Building Science was following some of its test data to show that a system where you controlled where the differences in moisture content occured was almost better than just controlling the where condensation temperature occured. Heady stuff. Contrarian appeal, too.
With pics, and documentation. LOL
<g>: http://www.cchrc.org/Reports/REMOTE%208-2-06.pdfOccupational hazard of my occupation not being around (sorry Bubba)
CapnMac
Thanks for the documentation.
Rich
Thanks for the documentation.
No sweat.
The thing about REMOTE/RESIST that has always fascinated me is how very applicable it is to my hot-humid climate as it is to an extreme cold environment.
That is not always the case with the various prescriptions for What Everyone Must Do that are out there (some of which are exactly wrong in my climate).Occupational hazard of my occupation not being around (sorry Bubba)
CapnMac
Thanks for the documentation.
No sweat.
I was just in a playful mood that day.
The thing about REMOTE/RESIST that has always fascinated me is how very applicable it is to my hot-humid climate as it is to an extreme cold environment.
I posted an article on vapor barriers in the thread on foam behind siding (Form FHB, because I am not smart enough to give advice with out documentation) and they were discussing how the foam keeps the wall assembly warm enough that condensation is not a problem even with an inside vapor barrier and foam under the siding. http://forums.taunton.com/tp-breaktime/messages?msg=102606.9
That's what the REMOTE article mentioned too. With that cold climate (Canada) they seemed to be pretty focused on the condensation near the outside of the fiberglass.
I was suprised that the REMOTE wall didn't perform signaficantly better than the standard wall 2x6 with foam on the exterior. I expected a greater difference in fuel usage.
Rich
Edited 3/24/2008 1:48 pm ET by cargin
wall didn't perform signaficantly better than the standard wall 2x6 with foam on the exterior
Makes me want to dig into the internals a bit--foam ought to help prevent bridging through the framing, which ought to increase the "assembly" values. Not that "ought to" is a rule or anything <sigh>.
The other thing that occurs to me is in window & door placement. The ratio of door and window area matters, too. (That's a major contributor to the "bomb shelter" look of the super-insulated structures, the wall to window/door ratio.)Occupational hazard of my occupation not being around (sorry Bubba)
I believe you run bathroom fans to increase the ACH.
Which only works if a window or door is open. And while the fan runs.
If a door or window is open, you are letting in untempered air (which could have a 30-60 or more DeltaT) which negates the superinsulation.
The make-up air supply is via passive air inlets (Airlet 100) which allow 5-20 cfm per unit, deflected up to the ceiling, and include a reed valve to partially restrict the inlet when there is excessive pressure differential (wind gusts or a door opening).
While this required minimum air exchange does impose a heating load, it hardly negates the advantages of superinsulation.
First, it's a controlled minimal air exchange at a known rate. And, while the infiltrative heat loss of my most recent house accounted for nearly 24% of total heat loss (second only to windows at 33%), the house still had a maximum design heat load of only 16,300 btu/hr for 2000 sf of conditioned space in an 8500 dd climate - pretty minimal by any standard.
With passive solar gains included, the effective system heat load is 1.42 btu/dd-sf.
By contrast, the average 1976 home was 15 btu/dd-sf, 1980 solar home study houses were 8 btu/dd-sf, and HUD/DOE Solar Award Homes were 4 btu/dd-sf.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/21/2008 12:28 pm ET by Riversong
I understand your methodology.You seem to be a little quick to assume that an HRV-equipped house is unlivable without the HRV, though.In most builder's infinite wisdom, they install the latest technology available. We know them as "windows". Many of them.. the really advanced ones.. open!!Pow, passive ventilation available whenever necessary.The rest of the time, you can enjoy low-flow heat exchange ventilation. That's hardly "ridiculous" and houses built that way certainly won't have to be abandoned or hurt their occupants. You can always punch your flow-controlled holes in the wall later if necessary, it's not like you have to tear down the house to retrofit.My personal only problem with active ventilation is I would prefer supply air to not have ducts. Sadly, HRV Airlets aren't available yet. that would make me happiest.. small, HRV, active airlets, no central ducting. Make them easy to clean and I'd hop up and down with joy.I'm not saying you build bad houses or anything. But "sealing it tight and venting it right" isn't "ridiculous", unhealthy, or indefensible either.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
"sealing it tight and venting it right" isn't "ridiculous", unhealthy, or indefensible either.
That's the way I build, but I don't aim for zero natural infiltration, I make sure the envelope can breathe and store moisture without damage, I minimize the use of toxic building materials to protect indoor air quality at the source, and include radon mitigation in all houses. And I try to keep the ventilation system as low-tech and, if possible, "off-grid" as possible.
In most builder's infinite wisdom, they install the latest technology available. We know them as "windows". Many of them.. the really advanced ones.. open!!
To build a super-tight house with a centrally ducted HRV and then require that windows be opened in the heating season when the power is down (and the central heat isn't operating) is ridiculous.
My personal only problem with active ventilation is I would prefer supply air to not have ducts. Sadly, HRV Airlets aren't available yet.
There are wall-mounted HRVs, but it seems they are made in the UK or Germany:
View Image
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Again, you need X amount of fresh air. Whether you open a window or punch a flow-controlled hole in the wall, you are doing *exactly* the same thing when the power is down. You can crack a window and keep the airflow fairly low. What exactly is so ridiculous about that?it's no more ridiculous than punch holes in the wall and calling it efficient. I understand it's not that bad and it's certainly better than nothing, but it's not the be-all end-all of IAQ ventilation, nor the only way to do it.I'll have to check out those wall mount units, thanks.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Whether you open a window or punch a flow-controlled hole in the wall, you are doing *exactly* the same thing
Well, yes, but only if the powere is off, so you have multiple problems at once.
If it's, oh 30, 40º outside, and you are tying for 67-68º indoors, that's around a 30º deltaT--that's a lot to "suck up" and re-condition (as opposed to "natural cooling" where the stat senses a 2-3º deltaT and "corrects" that change.
That's why you/we want to use the HRV; we want to decrease that deltaT as cheaply as possible, and blowing "waste" air through a duct to warm incoming air is a way to do just that.
The gotcha right now is that the amount of fresh air the occupants need/want looks to be 5 or 10 times the amount of leakage an "optimal" heating (insulation) envelope requires.
Brings us back to the refrigerator analogy. Refrigerator is a real efficient way to maintain a given temperature at a given economy. The problem with that economy is that it kind of goes out the window (NPT) if you need to ventilate that refrigerator to be able to breathe.Occupational hazard of my occupation not being around (sorry Bubba)
I don't understand what point you are trying to make.all buildings must ventilate to breathe.the question is entirely whether it's good enough to let it be unconditioned air (displacing your conditioned air) all year round, or whether you want to recover some of the heat/humidity conditioning you might have done.If all your heat is free, then I suppose letting your conditioned air float outside is no problem.Most people aren't in that situation though.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
all buildings must ventilate to breathe.
Ah, now I see.
The article claims that the natural breathing of the building is 1 air change in 100 hours (4 and a bit days) which is why so little energy is needed to heat the building.
That's fine and dandy. But, it may be over the top is the problem. Let's call "healthy" one air change in 4-8 hours. That's a lot of non-room temperature air to condition--ten times more than the stated energy budget.
Which could introduce a huge mechanical design flaw, if the goal is cost-efficient energy use. If we stick to 0.01ach, you could spec a near-passive radiant floor heat system. That system would be very inexpensive to run, as long as the building is vacant. Having people in there, though, could mean running HRV half or quarter days (or, more likely, 30min/hour). Going to spend money for tha fan energy. And, with the introduction of more unconditioned air, the heat system "runs" more often.
So, what that suggests to me is that "ordinary" insulated structures, designed for healthy air quality might make for better mechanical design, which is likely to give a better designed house. Occupational hazard of my occupation not being around (sorry Bubba)
In the end: you need X amount of air.If it comes through cracks, deliberately or not, you lose energy. Sticking with 0.01 ACH with no further ventilation is not an option; you'd die. Obviously there is ventilation occurring.You may spend energy to reclaim more of it via HRV/ERV, and gain control over the condition of the air while you are at it, or not. Don't forget to include whatever fan power you'd have from bathroom exhausts in your comparison, by the way.In some cases, it won't make sense use an HRV/ERV, particularly when energy costs are low. If you didn't spend much to heat up that air in the first place, you don't lose much letting it go outside.Normally though, in a "normal" very tight house, an HRV or ERV will save more than its electrical usage in energy costs and result in more controllable and better IAQ and comfort as well.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Normally though, in a "normal" very tight house, an HRV or ERV will save more than its electrical usage in energy costs
We must consider not just heating savings and electrical consumption, but also the installed cost of the unit, ducing, wiring, controls, etc.
Then, adding operating and maintenance costs and subtracting heat energy savings, allows a calculation of full cost and payback period.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Are we assuming we have any idea what energy costs are going to do?Calculate all you like. It's a fun exercise. No bearing on reality, but yeah, it's fun. I do like math. It's fun to see how little you have to do to halve or double payback periods, isn't it? ;)don't forget cooling, for many people, is also a good reason to use HRV/ERV. In vermont your issues are heating only. In new jersey, an ERV is a year-round energy saver.Point is entirely thus: there are multiple ways to skin the cat. Your attitude that there is only one way, yours, is myopic, insulting, and condescending. I'm not saying everyone needs an HRV, simply that they exist for good reason and houses that require them are not necessarily "ridiculous", as you said.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Point is entirely thus: there are multiple ways to skin the cat. Your attitude that there is only one way, yours, is myopic, insulting, and condescending. I'm not saying everyone needs an HRV, simply that they exist for good reason and houses that require them are not necessarily "ridiculous", as you said.
If you need to personalize this discussion and misquote me in order to make a point, then perhaps you don't have much faith in your own arguments.
I have never suggested that there was only one way to do anything, nor that "my" way is the appropriate solution to every circumstance. Nor did I ever suggest that the use of an HRV was "ridiculous" - only that clumsy responses to a failure in the high-tech system, such as opening a window on a super-tight house, were ridiculous.
"Build it tight, and open a window if necessary" does not make a good motto. If there is a way to design a more low-tech passive system that is failsafe, that is sensible on a variety of levels.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
i know a guy who could invent a control/hrv.... he can invent just about anything
what guidelines would i give him ?let's say 1200 sf or 9600 cf for our sper insulated house what we really want is a healthy air..... the guidelines say WHAT ? 5 air changes /day ?what do they say ?
if we have an AIR QUaLITY meter/control then we really don't care what the number of changes is.... i'm thinking it could run a muffin fan thru an HRVhey this guy was designing differential controls back in the '70's and the Mosquito Magnet in the '90's.....he could do it... and the mind-meld here could give him the parametersMike Smith Rhode Island : Design / Build / Repair / Restore
the recommended guidelines for fresh air have done little but change for 30 years.I personally design for a max capacity of 0.5ACH for spot exhaust, consistent capacity of roughly 0.35ACH, and I don't expect the fan to be run 100% in that case.humidistats are good, but you're not going to get a comprehensive pollutant sensor at this point for any sum anyone would want to spend.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
it is a strange beast to try to corrral..
what is goig to affect the indoor air quality......... everything !
the outgassing of the materials
the outgassing of the occupants
any combustion products in the house
cooking
cleaningand then we have to determine is the outside air really an improvement over the inside air
ie: just bringing in fresh air is not neccessarily bringing in good air.. never mind the temperature
my inventor friend is going to think on it
but like you said.... good luckMike Smith Rhode Island : Design / Build / Repair / Restore
the outgassing of the occupants...
View ImageView Image
and then we have to determine is the outside air really an improvement over the inside air
The EPA has determined that indoor air quality is one of the top five environmental public risks, in part because the typical American spends 90% of their time indoors.
http://www.epa.gov/iaq/pubs/insidest.html#Intro1:
"In the last several years, a growing body of scientific evidence has indicated that the air within homes and other buildings can be more seriously polluted than the outdoor air in even the largest and most industrialized cities."
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/24/2008 11:57 pm ET by Riversong
do you really not see that you are saying exactly what you say you are NOT saying in that post? I see, HRV's aren't ridiculous, just (in affect) any house design that uses one is? That is not exactly a fair minded assessment, and it is exactly the logical conclusion of your statement.One more time, I will ask, exactly what is more ridiculous about opening a window in the infrequent and temporary event of a power or fan failure, when the passive systems you are designing are, in fact, basically "open windows" 24/7/365 forever? It has to be foolproof to be an improvement? Is physically opening a window now asking too much?
-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
"That system would be very inexpensive to run, as long as the building is vacant."Does anyone know of a way to measure the real-time ventilation needs of a structure?If you're building a house with .01 natural ACH, I think there's a need to be very precise with all calcuations. I don't see this precision when it comes to determining the amount of ventilation needed.We have thermostats that call on the HVAC system only when the temperature hits a specific point. If you have 40 people over for a party in mid July, the AC will cycle more often to deal with the sensible and latent loads.We have installed bath fans hooked up to a humidistat to fix "damp" bathrooms (children not wanting to turn the bath fan on when taking a 30 minute steam shower). Obviously, the fan doesn't run when not needed.I have not seen any whole house ventilation that can adjust to the needs of the house at any given time. If we employ active ventilation, whether it be through an HRV or not, shouldn't there be some means by which the ventilation rate can modulate to meet the needs of the moment?Riversong says he builds non-toxic houses for non-toxic people. If his house is vacant for a month, it may be fine with .01 ACH.What if his clients sold the house to a family whose furniture has more off-gassing than the 2007 International Chili Society cookoff. I would think that would mean disaster.Maybe there are some sensors out there that I'm not aware, but it seems like we're relegated to leaving the ventilation almost to chance.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
Does anyone know of a way to measure the real-time ventilation needs of a structure?
That question was posed earlier (was that you?)--I still have no good answer for it.
It would seem like some form of CO/NO/CO2 monitor would give a 'reading' of how many folks were in the sturcure, if any.
This "air quality" air change issue is relatively brand new, and subject to no small amount of debate, as we have seen here. Technology for monitoring/correcting that is probably still catching up. Think how long it has taken for humidistats to become common.Occupational hazard of my occupation not being around (sorry Bubba)
"That question was posed earlier (was that you?)--I still have no good answer for it."Yes, that was me earlier.I thought if I repeated myself, like a child stomping his feet and clenching his fists, I would get some attention.I really do not know too much about the ventilation side of things. I just struck me that the building designer has to accurately guess the needs of the building. If he's wrong, you either waste money with too much ventilation or breathe bad air.It just doesn't seem right.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
It just doesn't seem right.
My grandfather used to opine that a professional is someone who makes an incredibly difficult task look easy. And that ease is part of why we watch olympic competition. After all, if that narfle can do a triple axel that badly, how hard can it be ?
Not that I'll be mistaken for any kind of professional--only thing I know well is that i don't know that much well.
That, and I'm far too used to trying to find compromise solutions for complex climates (it dropped below 20% humitiy of six different days this winter! Alors!)Occupational hazard of my occupation not being around (sorry Bubba)
Riversong says he builds non-toxic houses for non-toxic people. If his house is vacant for a month, it may be fine with .01 ACH.
What if his clients sold the house to a family whose furniture has more off-gassing than the 2007 International Chili Society cookoff. I would think that would mean disaster.
Except my last house testes at approximately 0.11 natural ACH with the Airlets taped and 0.15 natural ACH with them open. And I have programmable timers on each of the two bathroom exhaust fans to run them 20 minutes out of each hour to guarantee a minimum of 0.25 mechanical ACH, which is the minimum for safe indoor air quality.
The ASHRAE standard for minimum ventilation rate: 1 cfm/100 sf plus 7.5 cfm/# bedrooms plus 1.
Does anyone know of a way to measure the real-time ventilation needs of a structure?
If you're not programming the ventilation to conform to ASHRAE/code standards, then another strategy is to use a centrally-located dehumidistat set at 40%. But be careful not to locate it too close to kitchen or bath or localized humidity (which should be evacuated by occupant intervention) will run the whole house system. And the occupant needs to know to shut the dehumidistat off in the summer when humidity is high.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/24/2008 6:51 pm ET by Riversong
The ASHRAE standard for minimum ventilation rate: 1 cfm/100 sf plus 7.5 cfm/# bedrooms plus 1.
I'm not disputing what the standard is. I'm saying that a standard that is supposed to be good for every residence in the country probably means that some houses complying with the standard have too much ventilation and some have too little.
If you're not programming the ventilation to conform to ASHRAE/code standards, then another strategy is to use a centrally-located dehumidistat set at 40%. But be careful not to locate it too close to kitchen or bath or localized humidity (which should be evacuated by occupant intervention) will run the whole house system. And the occupant needs to know to shut the dehumidistat off in the summer when humidity is high.
Is humidity the primary "pollutant" that needs to be exhausted? I would think that there are several other factors that come in to play.
Or are you saying that the humidity level would be indicative of the number of occupants and therefore the amount of ventilation required?
Ventilation seems to be like a vapor barrier. Sometimes you need a VB on the warm side, sometimes on the cool side, and sometimes you don't want any VB at all. The difference is that ventilation rates can easily be controlles with dampers and controls.
I don't know if I'm communicating well, but the frustration expressed earlier in the thread with the paradox of super air-sealing while still needing a sufficient number of ACH is what got me thinking. To go to great lengths in sealing up the house but not ventilating on an as needed basis seems counter-intuitive. If there were a way to limt the energy loss to ventilation by only bringing in the necessary amount of air seems to be the logical step.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
Is humidity the primary "pollutant" that needs to be exhausted? I would think that there are several other factors that come in to play.
Or are you saying that the humidity level would be indicative of the number of occupants and therefore the amount of ventilation required?
Excessive humidity is the best indicator of insufficient air exchange in a tight house.
the paradox of super air-sealing while still needing a sufficient number of ACH...
It's not a paradox at all. Uncontrolled air leakage is just that - unreliable. It increases with increased delta-T (stack effect) and with wind, and it leaks in and out at different places - not necessarily where it's most needed. Additionally, the movement of heated air up into the attic (by stack effect) often results in moisture damage, and drawing in basement air can increase radon concentrations.
Making a house tight eliminates uncontrolled ventilation and allows for a design strategy for the correct amount of air exchange from the correct locations.
ASHRAE is considering a higher recommended ACH (0.50) for houses built with lots of manufactured wood materials that offgas formaldehyde.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
I'm not saying we should stop air sealing our houses because we need ventilation anyway. That's throwing the proverbial baby out...What I am saying is that if you build a house that needs .25 ACH to function correctly and you ventilate it with .5 ACH, you're basically heating 100% of the houses volume every 4 hours needlessly.Would you agree with that statement?
Jon Blakemore RappahannockINC.com Fredericksburg, VA
What I am saying is that if you build a house that needs .25 ACH to function correctly and you ventilate it with .5 ACH, you're basically heating 100% of the houses volume every 4 hours needlessly.
Would you agree with that statement?
Not exactly. I would say that you're unnecessarily heating 25% of the house volume every hour ;-)
But that's why it's important to make the house as tight as possible to eliminate the highly variable natural air exchange (which will increase when you need it least - when it's colder or windier outside), and to design a ventilation system (however low- or high-tech) to provide just enough air exchange and in the right places.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Would you agree with that statement?
Not entirely. Building the insulation/VB envelope down to 0.2 and 0.1 is better for the insulation, the window & door openings. Potentially better for the occupants, too--they are less likely to get a chill from an errant breeze and crank the stat up 5,6, 10º to take that chill away.
The thing that bothers me in this is the "super" part of the superinsulation. I'm not sure going to "super" is that much better than merely going to "insulated." There's a balance in all things, and the "super" part of it seems to lean too far in one direction to my perception.
RS will, I'm pretty sure, make an argument for controled ventilation, rather than uncontrolled infiltration/exfiltration. I'd agree with that. Now, achieving it, that's a different animal, too. Consider that all those expensive filters are not much use after a person opens a window--which makes this time of year very hard on allergy sufferers. (Tho- there's a growing school of thought that out isolation from natural irritants may increase our sensitivity to them in our heavily-conditioned spaces.)Occupational hazard of my occupation not being around (sorry Bubba)
Building the insulation/VB envelope down to 0.2 and 0.1 is better for the insulation, the window & door openings.
I think it's important to change our language and our thinking on the basics of the thermal envelope. Rather than insulation/VB, we need to think in terms of thermal envelope/air barrier.
The actual insulation material is only a part of the thermal envelope and all pieces of the cross-section need to be considered for proper performance. And, since we now know that vapor diffusion from the inside out during the heating season presents a minimal moisture challenge to the envelope and that almost all envelope moisture (from the inside) is due to air movement, let's drop the VB idea and think in terms of air barriers.
The thing that bothers me in this is the "super" part of the superinsulation. There's a balance in all things, and the "super" part of it seems to lean too far in one direction to my perception.
How do you calculate that "balance point", or point of diminishing returns?
If it's in terms of dollar payback over time, then one must balance today's dollars for additional insulation against the escalating cost of heating energy (and the depletion of the earth's non-renewable fossil fuel resources - we're already at global peak oil and going downhill fast).
Another way to calculate that balance point is comparing additional carrying costs of a better insulated structure (monthly mortgage payments) to the net savings in monthly utility bills.
I can build a superinsulated house which will cost the owner less the first month of occupancy because the utility savings are greater than the additional carrying costs. Banks (at least before the meltdown) sometimes offer larger debt-to-income ratios for people wanting to mortgage a highly energy-efficient house because the monthly non-mortgage costs are lower.
From my perspective, even with current energy prices, it's not sensible to build a house with less than R-40 walls and R-60 ceilings. For tommorow's energy prices, such a house will seem minimalistic.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/25/2008 10:58 am ET by Riversong
let's drop the VB idea and think in terms of air barriers.
I'm still old-fashioned, and have not yet quite changed my terminology ways. Yet. "Air Barrier" explains it much better, with a dollop of consideration applied.
And, humidity is a huge part of my climate here in the river bottom, too (only about 200-220 days of the year where the ambient humidity will support mildew).
How do you calculate that "balance point", or point of diminishing returns?
That's the trick of it. Some of it has to be the life cycle costs you cite. Some probably ought to be in the transporation and construction "mass" too--probably less-desireable to truck ICF in from 6 states away as much as delivering concrete from a county away.Occupational hazard of my occupation not being around (sorry Bubba)
Hudson... all excellent posts
couple things
Net wall is total wall - ( doors, windows & anything else in the wall that should be calculated seperately
U = 1/R
R= 1/U
sometimes you can find one listed and need to convert to the other
the basic formula is this:
BTuH = Area x delta-T x 1/U
you also want to know things like ( LF of edge crack ) to calculate infiltration
there are so many free downloadable programs out there
but the ResCheck is pretty helpful
also.. if you do (Room-by-room loss .... AND ( whole house loss ) .. they should give you a check on each other....AND you can use the room by room to help your discussions with your heating sub
foundations and slabs on grade are a little trickier because you have to account for different conditions
the thing to keep uppermost in your analysis is (heat moves from hot to cold ) any time you have a delta-T you will have a loss
and any infiltration must be accounted for
and any air you exhaust has to be made up ... if you don't make it up you will turn your structure into a vacumn.. and you can have water leaks that seem impossible
it is better to have a slightly positive air pressure rather than a negative one, and neutral is best
( unlike a contract... where you can make money, lose money, or break even )
when we had large heat losses , the calculations were not as important... just get a bigger furnace, and more baseboard
now.. with super insulation..... the calcs are more critical
Mike Smith Rhode Island : Design / Build / Repair / Restore
I would like your opinions on a wall design for my subarctic region. I am considering a modified Mooney wall.
The M/W would be modified in the following manner
2x6 studs with the ripped 2x2 facing on 24".
Exterior metal cross brace let into the 2x6's to meet lateral strength requirements.
(This is something new I saw in either FHB or JLC, its a folded V with ears, cut the kerf and nail the ears to the studs).
1-2" of Blue board XPS over the exterior.
20lb felt moisture barrier
Hardie plank siding.
Interior insulation would be local produced denspac cellulose with the inslul web screening.
This would be single story (2ksq ft.) on a frost protected insulated slab. (Monolithic pour) with radiant in floor heat. 6" blue board under the slab.
Anderson 400's for windows or near equivalent.
Any opinions if this would be practical for this climate?
I plan on adding plumbing for the vacuum-tube solar collector (Jan 08 JLC) or installing it at the time of building to use with the on demand hot water heater and the small boiler for the RIFH.
I was pricing SIPs and locally they are cost prohibitive. I was quoted $12K (just for the transportation) per truck and that quote was variable depending on fuel costs.
ICF's are also expensive around $26 per block plus $120 per yard of concrete.
Thanks
Jim
jim.... Where is this "sub-arctic region " ?
1) are the 2x6 @ 24" oc or the horizontal 2x2 @ 24" oc ?
2) ... i've used the metal t-brace... but i had to stop because my BI wouldn't acccept it as equal to the plywood sheathed corner
3) 1-2" of Blue board XPS over the exterior. ... is that 1/2" or 2"
if it's 1/2" , then it isn't worth the trouble
4) i've seen hardie applied over 1" blue styro-SM ... but i didn't like it
i'd prefer to see studs ( with your t-brace, if allowed )... then the 1" styro -SM
THEN 1/2" plywood ( or osb ) for a nailbase.. it makes life a lot easier for cornerboards, window installation, and other trim details
if you have any kind of vermin in your area ( like carpenter ants, termites, or other bugs ) then i'd only use borate treated EPS foam.. which is slightly less in terms of R-value.. and less in terms of costMike Smith Rhode Island : Design / Build / Repair / Restore
Mike, sorry I didn't identify my location. Wasilla Ak, 10K degree heating zone.
are the 2x6 @ 24" oc or the horizontal 2x2 @ 24" oc ?
2x6 24 oc vertical studs, double top plate, pt bottom plate
2) ... i've used the metal t-brace... but i had to stop because my BI wouldn't acccept it as equal to the plywood sheathed corner
Good point.
3) 1-2" of Blue board XPS over the exterior. ... is that 1/2" or 2"
if it's 1/2" , then it isn't worth the trouble
A: 1 to 2" of bb
4) i've seen hardie applied over 1" blue styro-SM ... but i didn't like it
i'd prefer to see studs ( with your t-brace, if allowed )... then the 1" styro -SM
THEN 1/2" plywood ( or osb ) for a nailbase.. it makes life a lot easier for cornerboards, window installation, and other trim details
A: Point well taken I am flexable and can incorporate that instead of the metal.
if you have any kind of vermin in your area ( like carpenter ants, termites, or other bugs ) then i'd only use borate treated EPS foam.. which is slightly less in terms of R-valu
A: We don't have termites, have seen a few carpenter ants around but not much of a problem.
Thanks for the quick reply.
Jim
jim...
<<<
A: Point well taken I am flexable and can incorporate that instead of the metal. >>>
i don't think it's an either / or choice.
if your BI allows the T-brace.. great
but the plywood should not qualify as a shear panel unless it is in contact with the studs..
if it is nailed on top of 1" or 2" foam.. then you are relying on the NAILS to give the shear strength.. they can't do that .. they'll just bend
so.. it's either he allows the metal t-brace or you can't use the foam unless it goes OUTSIDE the sheathing.. then you're right back at the nailbase /trim problem.. plus you potentially have your shathing within the dew-point zone.. not goodMike Smith Rhode Island : Design / Build / Repair / Restore
: Point well taken I am flexible and can incorporate that instead of the metal. >>>
i don't think it's an either / or choice.
if your BI allows the T-brace.. great
but the plywood should not qualify as a shear panel unless it is in contact with the studs.. I agree on that.
if it is nailed on top of 1" or 2" foam.. then you are relying on the NAILS to give the shear strength.. they can't do that .. they'll just bend. I would not do that at any rate.
so.. it's either he allows the metal t-brace or you can't use the foam unless it goes OUTSIDE the sheathing.. then you're right back at the nailbase /trim problem.. plus you potentially have your sheathing within the dew-point zone.. Question would not the vapor barrier behind the sheetrock prevent that possibility?
Then I am back to putting in furring strips, it sounds do-able but a major pita
OK what about this plan then, instead place Icynene over the 2x6 studs up to the level of the horizontal strapping on the inside. Roughly 8" deep. Forget the celulose. Would that cost aside be a tighter house with a fairly high r value? At least quite a bit higher than cellulose.
Tlisher2
so.. it's either he allows the metal t-brace or you can't use the foam unless it goes OUTSIDE the sheathing.. then you're right back at the nailbase /trim problem.. plus you potentially have your sheathing within the dew-point zone.. Question would not the vapor barrier behind the sheetrock prevent that possibility?
I think Riversong is advising to do away with the vapor barrier and let the cellulose absorb and release the interior vapor.
http://forums.taunton.com/tp-breaktime/messages?msg=102383.136
I am not sure all the BI across the country got that memo.
But what he was saying was that the air movement ( from leaking wall construction) was what was moving the moisture to the outside wall.
OK what about this plan then, instead place Icynene over the 2x6 studs up to the level of the horizontal strapping on the inside. Roughly 8" deep. Forget the celulose. Would that cost aside be a tighter house with a fairly high r value? At least quite a bit higher than cellulose.
I don't understand.
Check out this post earlier in the thread. There is a link to a builder in Maine who does a double 2x4 wall with OSB holding the studs apart.
A good insulation package and good air sealing is what you should be striving for.
http://forums.taunton.com/tp-breaktime/messages?msg=102383.25
Rich
Edited 3/25/2008 8:55 pm ET by cargin
Edited 3/25/2008 8:59 pm ET by cargin
Not sure what you don't understand, instead of a mooney wall with cellulose use the same design but substitute icynene (foam in place closed cell insulation) instead.
That with a VB on the inside of the house, which may be redundant at that point because we do not have high humidity here, never gets much above 50% and most of the time the problem is quite the opposite. I saw a low of around 10% this winter here. I do think that where I am building at this time there isn't any BI's. By the time I am ready to build there will most likely be some though.
Jim
Talisker2
Do you mean spray foam the 1st 8" then go with Cellulose?
I don't think the cost of the foam would be worth it.
Air seal your wall and dense pack your wall with cellulose , and I don't think you would have any problem with condensation in the wall.
The only problem i see with the mooney wall (2x4) is that it is not deep enough.
I like the concept of a deeper wall, with 1x3 furring strips (horizontal) and 3/4" backing where needed. As discussed very early in this thread.
Rich
Do you mean spray foam the 1st 8" then go with Cellulose?
I would spray the walls and lid with foam to the depth of the 2x6s' + the depth of the horizontal strapping. Roughly 8" worth.
I might use Cellulose in the lid. Keeping a cold roof.
Air seal your wall and dense pack your wall with cellulose , and I don't think you would have any problem with condensation in the wall.
I agree, but the BI will (and here I am only guessing) will require VB no matter what is on the walls.
I like the concept of a deeper wall, with 1x3 furring strips (horizontal) and 3/4" backing where needed. As discussed very early in this thread.
I do too, see first comment at the top of the page.
Jim
This would work.
I would definately go with 2" exterior XPS in your climate.
Forget the Icynene, it has lower R/in then dense-pack cellulose and the cellulose will help moderate moisture - don't use a vapor barrier.
Metal T-bracing has been around for decades, and will meet code in many areas. You do, however, need to use opposing angles from plate to plate on each wall, as many as will fit between openings. And nail with (2) 8d at each stud and (2) 16d at each plate.
Felt comes in 15# or 30#. Either would work.
If you use plywood nailbase exterior to the foam board, be sure to nail siding through it at the studs or the nail penetrations through the foam can diminish the R-value by as much as 39%.
Why use a boiler and an instantaneous heater when either will supply both heat and hot water? I would recommend an efficient boiler with an indirect water tank. You'll get longer service life, more efficiency, and more hot water.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Riversong, that is what I am looking for (your comments are right on). My only hope is I can get buy with out using a VB and sealing the exterior tight enough. It will depend on the BI or the Borough planning dept. say exactly what I can do tho.
Jim
Two questions.
I would definately go with 2" exterior XPS in your climate.
Why not a Larsen truss? Or are you just saying that if Taliskier2 is going to build a 2x6 wall with strapping that he should also add the foam on the exterior? I would think a Larsen truss would be optimal for his climate.
If you use plywood nailbase exterior to the foam board, be sure to nail siding through it at the studs or the nail penetrations through the foam can diminish the R-value by as much as 39%.
Could you elaborate on this? I would expect some reduction, but 39% seems like a lot more than my shooting from the hip guess would be.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
Why not a Larsen truss?
Sure. A Larsen Truss or staggered double-stud wall, I believe, is a far better option for superinsulation. But the OP was asking for feedback on the system he had chosen. And every time I suggest the LT, I get accused of thinking there is only one solution to superinsulation. There are many solutions - but the LT is best ;-)
nail penetrations through the foam can diminish the R-value by as much as 39%
Could you elaborate on this?
It does seem like an extreme case, but I got this number from a reliable source (which I can't now remember).
If you consider the very high conductivity of steel, the effect of nail penetration is may times worse than the same number of holes in the foam. And the cold steel tips also make great condenstion points.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Just for fun, here's a truss wall system the inventor claims is an improvement over the Larsen truss wall. I can see where there there would be labor savings, but it looks like it would be a good bit more expensive that your construction using local green wood. Plus it uses more wood and metal.
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5617693.PN.&OS=PN/5617693&RS=PN/5617693
Billy
Just for fun, here's a truss wall system the inventor claims is an improvement over the Larsen truss wall.
An "improvement" only in that it trades off site labor for factory labor by making the truss with gang plates off-site.
My modified LT wall is already a vast improvement over the original LT system, and I'm modifying it further for my next project using KD lumber and CDX into a hybrid of a LT and a staggered stud wall.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
My modified LT wall is already a vast improvement over the original LT system, and I'm modifying it further for my next project using KD lumber and CDX into a hybrid of a LT and a staggered stud wall.
I'd bow reverently to your "vast" humility ~!~ but looking at the photos all I can see is an awful lot of tedious work, making up those truss members, and installing all the extra pieces required by that puzzle.
I might yet be convinced to build a house like that but how about showing a full set of photos, the whole process. For example, how do you scaffold when installing outside, ballon section of the truss?
I'd like to be able to relate to this concept/method from a more pragmatic, carpenter's POV. So give me the Dick and Jane version, lots of pictures with simple descriptions.
all I can see is an awful lot of tedious work, making up those truss members, and installing all the extra pieces required by that puzzle.
It's not particularly tedious, other than the fabrication of multiple half-trusses (outer chord and gussets) on a template that makes it quick and easy. Framing out the windows is easy and the whole truss system becomes a jungle jim for easy climbing.
how do you scaffold when installing outside, ballon section of the truss?
That's part of the beauty of this system - no scaffolding required. Once the outer half-trusses are fabricated, the bottom section is nailed to the outer plate and the gussets (which are also the wall width gauges) are gun-nailed to the sides of the studs from inside, with the upper extension chord nailed from inside the second floor.
The only staging needed is for siding installation, and after each lift is installed the second coat of stain is applied. And I use simple, site-built scaffolding which is easy to erect and to move.
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Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/26/2008 11:06 pm ET by Riversong
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Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/26/2008 11:11 pm ET by Riversong
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Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/26/2008 11:13 pm ET by Riversong
Not that it matters to you, but if I allowed scaffolding like that on one of my jobs I better have a great line of credit at my local bank to pay off OSHA when they come visit. Is Vermont an OSHA free zone?
They can't get your Goat if you don't tell them where it is hidden.
Is Vermont an OSHA free zone?
Not exactly. Vermont, like most states, has its own VOSHA. But we're a small, very rural state with no state building codes, only in the few cities.
Thankfully, VOSHA doesn't have the person-power to inspect every building site in the state. It's mostly geared toward worker safety in employment, not where a few self-employed carpenters come together to build someone a house.
Builders relied for hundreds of years on their own ingenuity and wisdom when it came to building scaffolding. While I don't have the statistics, I suspect that the number of buiding-site worker accidents has risen dramatically since contractors began relying on pump-jacks and pipe staging and lost the common sense it took to build scaffolding safely.
I've never had a scaffolding accident in 25 years of building? But I've known others who have been gravely injured on pipe staging and with fall-arrest systems.
If you feel you need to bow to the Lords of OSHA rather than use (and be willing to defend) common sense and timeless practice, that's your choice. It's not mine.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Thanks but I'll gladly take a properly erected pipe scaffold over all kinds of home made scaffolding. I had some good, old fashioned, carpenter's creations collapse under me when I was an apprentice.
It's obvious that you consider yourself to be exceptional. In some areas of knowledge, that may be true. But that attitude is what leads to "accidents".
BTW, OSHA is in the business of taking bribes, not worker safety.
It's obvious that you consider yourself to be exceptional. In some areas of knowledge, that may be true. But that attitude is what leads to "accidents".
Exceptional only in the sense that I put my faith in common sense, which has become the exception rather than the rule.
It's carelessness and a blind faith in "failsafe" technology that causes accidents. As I said, I've had no "accidents" in 25 years of building. That's not an accident.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Ahhh, I knew it had to be that I was a govt. toady . It couldn't possibly be that you are breaking a Law and refusing to follow procedures that the rest of us follow in the interest of seeing our people go home to their families at the end of the day. http://www.osha.gov/SLTC/etools/scaffolding/supported/frame/fallprotection.htmlDo you drive without a license and insurance as well?
They can't get your Goat if you don't tell them where it is hidden.
It couldn't possibly be that you are breaking a Law and refusing to follow procedures that the rest of us follow in the interest of seeing our people go home to their families at the end of the day.
First of all, if I'm failing to blindly follow any law, it's a small "L" law. I follow the Law, which is the natural law of consequences, and the proof - as they say - is in the pudding.
And, since I'm not an employer, I don't have "our people". In Vermont, we're each free and sovereign individuals.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
""And, since I'm not an employer, I don't have "our people". In Vermont, we're each free and sovereign individuals."" At the risk of picking some nits when I speak of "our people" I am referring to any and all co-workers. Employees, partners, sub-contractors etc are all included in the phrase. Under OSHA any time two or more individuals work together and one gives guidance and directive to another then the directing party is considered the responsible party. So don't tell any one how or where to place any materials . Vermont is no more different than any other place some individuals think they are better then the rest.
They can't get your Goat if you don't tell them where it is hidden.
Vermont is no more different than any other place
Ask any Vermonter and they'll tell you otherwise (but let's keep it a secret - there's too many flatlanders moving here as it is).
As for OSHA safety rules:
If you follow those rules because you feel they make sense and are for the good of "your people", then you are to be commended for that.
If you follow those (or any other) rules out of fear of repercussions, then you have chosen to be a slave and you are to be pitied for that.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
""If you follow those (or any other) rules out of fear of repercussions, then you have chosen to be a slave and you are to be pitied for that. So do you have a drivers license and insurance? Oregonians feel just the same as Vermonters. You should think about changing your name and tag line to something along the lines of "Solomon , Judgments for the World". ;-)
They can't get your Goat if you don't tell them where it is hidden.
You should think about changing your name and tag line to something along the lines of "Solomon , Judgments for the World".
Thank you. I appreciate your recognition of my wisdom.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Robert
there's too many flatlanders moving here as it is).
I resemble that remark. LOL
Here in Iowa you can see the grain elevator 10 miles away. Flat as a table in many places.
Rich
Robert
That looks like an old cast iron Makita miter saw. I had one for years until it finally gave out. Great tool for it's time.
Thanks for the pics. Better than a thousand words.
Rich
That looks like an old cast iron Makita miter saw.
That old saw belonged to two groups of Mutual Self-Help Housing families (built 17 houses) before it was given to me as a thank you.
I've used it for 25 years since and, though it keeps threatening to quit on me, a little fussing with the brushes and it fires up again. It's almost indestructible. And still accurate.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Robert
I just remembered I gave mine to my father in law. It still running. A liitle sloppy in the indents. But very good for staight cuts.
It's heavy though and I broke one leg by dropping it out of a truck once.
He just cuts firewood (small stuff) with it. I'll get it back from him when he doesn't need it any more.
One of the first major tools I ever bought in the early 80s.
Rich
still have our makita chop... use it for steel, rebar, steel stud , etcMike Smith Rhode Island : Design / Build / Repair / Restore
Mike
I have been really enjoying this thread.
Lots of good input. I can't share much because I am just sitting back learning.
But I'm watching and reading.
Some of the calc are difficult for me to comprehend. I am usually reading thru this quickly at night and I don't have time to wrap my mind around it. And I have to do it to learn it.
But I have bookmarked this thread in my file or future reference. Lots of good links too.
Good to know you're part of the old Makita miter saw fraternity. Out here they are miter saws. Chop saws have an abrasive wheel and are used solely for cutting steel and they don't miter. LOL
Rich
well, it wasn't a tilt miter, right ?
i thought that was the difference.. if it could tilt ... you upgraded it to a "miter-saw"
if all it can do is pivot... we call it a chop saw... anyways... most of the time it gets used for "chopping " aluminum into small pieces so we can store it for resale
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Mike Smith Rhode Island : Design / Build / Repair / Restore
Edited 3/27/2008 10:39 am ET by MikeSmith
Mike
Let me teach you Iowan.
That is a miter saw.
If it tilts then it is a compound miter saw or a double compound.
They guys in metal fabrication have a chop saw with an abrasive blade.
LOL Regional differences. But at least you will know when when you come out here for a job. Then you won't make a fool of yourself. LOL
Rich
i don't think i tried hard enough if i can't make a fool out of myself at least once a dayMike Smith Rhode Island : Design / Build / Repair / Restore
hudson.... i asked my inventor cousin about an air quality sensorand he came up with one off-the-shelf :http://www.bapihvac.com/AQS_Room.htmlists for $350 .... combine it with a pair of mini-HRV's.... and i think we're oto somethingMike Smith Rhode Island : Design / Build / Repair / Restore
i've been thinking about the various wall systems we're discussing here and i have some preliminary conclusions:first thing is ALL HOUSES are compromises and all the components likewise2d... in terms of the WALL...the R- level we decide on is arbitrary..... Robert has decided that 12" and R-40 is where he wants to be.. and he's willing to do the work to get therewhat did we come up with for the 2x8 wall .... i'm sure i can build that wall on the deck and tilt it up... i'm sure i can use 1/2 plywood sheathing.... and i'm sure i can use fiber cement siding.... so in terms of doing what i know... i won't be doing a modified Larson Trussif i wanted an r-40 wall , i'd go with the I-joists and Mooney the interior, 1/2 " sheath the exterior
i can build this wall using the techniques we already have... and i'd never adopt a wall that has no sheathing and applies the siding right over the studs
i would use a sheathing like Thermo-Ply ( 1/8 " foil-face "cardboard" ") it meets the shear requirements in our jurisdiction and most others too ( i built a 5,600 sf commercial building, our own 2-story gambrel & a 2-story three-car garage with ThermoPly )so....based on labor costs and compromises.... i'd build the 2x8 with the 2x2 mooney and cellulose dens-pak insulationand i'd use one or two of those new air quality controls i just postedbut i like the 1/2" ply or osb for a nailbase/ shear panelMike Smith Rhode Island : Design / Build / Repair / Restore
Mike, I appreciate you providing a straight forward analysis of all the wall building methods and ideas we've been discussing in this thread.
I've been off plumb in the same direction since we got started here, mostly due to being old and set in my thinking, I suspect.
Maybe I'll be willing to try something other than a 2X8 sheathed Smith-Mooney wall on a home further in the future but for now, I'm happy to add structure while conforming to methods I know well, are accepted, and whose outcome I can predict.
Mike,
I had another thought about the 2X8 Smith-Mooney wall, when built as multi-story. That 7+ inch width would allow the joists to be cut short, placing the ledger near the center of the of the wall and boxing the outside face. This would create a thermal break and allow for 2+inches of XPS between the box beam and the ledger.
How's that sound?
Edit: Another way would be to place the ledger on the inside edge of the wall with joist hangers, thereby creating a 4+inch cavity between the ledger and box beam.
Using a hole saw between the studs above, the cavity could be accessed and filled with cells. Of course, whether that's practical depends on how many holes would be needed.
Still, it's a 4+ inch space and break. How much R-value does 4" of XPS have?
Edited 3/28/2008 7:00 pm by Hudson Valley Carpenter
Keep this thread going, guys. I'm liking this one.
Keep this thread going, guys. I'm liking this one.
Hummm. Mongo like.
;-)
Mongo
How about some input from you?
I've been doing plenty of watching too while those who know more than me discuss things like ventilation.
Rich
Rich, I'm into this. I did my first house with TJIs as "studs" and DP cells 8 years ago. I lean towards polyiso and DP cells.The irony is I submitted plans for an addition to be built with 16' 2x8 "studs" 14 months ago. The building department is scratching their head as to "why". Part of it is because it is balloon framed (9' 1st floor, second floor platform, then 5' kneewall) so it's part structural, part insulation. But still, it's not "typical".My old building inspector "got it". He's gone though. His replacement is a clueless sort.But man, I dig this stuff. Super-insulation, net-zero, off the grid. If I wasn't so in love with two 60' oak trees that shade the south side of my house, I'd drop those suckers and put photovoltaics on my roof.Step-by-step.Mongo
Edited 3/28/2008 9:24 pm ET by Mongo
Mongo
I did my first house with TJIs as "studs" and DP cells 8 years ago.
How deep? What was your R-Value? What air sealing techinques did you use?
I lean towards polyiso and DP cells.
Do you mean 2x8 walls, w/ densepak and then polyiso on the exterior?
The irony is I submitted plans for an addition to be built with 16' 2x8 "studs" 14 months ago.
Are they still sitting on it?
If I wasn't so in love with two 60' oak trees that shade the south side of my house, I'd drop those suckers and put photovoltaics on my roof.
Gotta love those trees.
PV is quite expensive. Most cost effective is problably solar water heating at this point. Other than passive heating.
I am very interested in this topic and this thread is fun. Some day I would like to build a smaller, efficient house and shop. I don't know if you can justifiy the cost of going off the grid yet. Back in the 80s boy I was all over that, Mother Earth News stuff, but reality (kids and life) set in and here I am today on BT and dreaming.
Rich
Rich, You're my brotha from anotha mutha!When I was 12 I devoured Mother Earth, Rodale's New Shelter, all that mid-70's "alternative" stuff.But then I got married 20 years later! So my house, which I built solo, is 4100 sqft. With my kids going off to college in a few years I'm back to thinking about a 1700-2000-ish sqft house, well insulated, etc, etc.I need a kitchen/living room. An entertainment/home theater room. A library. A master bedroom and a guest bedroom. A couple of places to go potty.I doubt I'd ever get my wife to leave this place, though. But still, this is the first place I ever built, and I built well, so I'd love to stay here. It's just bigger than I need.TJIs were 12" deep. Caulked the plates, Tyvek on the exterior, no VR on the interior.DP cells everywhere nowadays, but I like polyiso in the attic. Keeps the attic cool in the summer, warm in the winter.Yup, they sat on the plans. Stamped and everything. If I don't get the go ahead, I'm going to build anyway. Mongo
i asked my inventor cousin about an air quality sensor
and he came up with one off-the-shelf :
http://www.bapihvac.com/AQS_Room.htm
That's takes all the guessing out of the equation, for any environment. Nice.
I've already forwarded that link to my sister, who's a public school teacher and has suffered with nearly every airborne illness that goes around her school.
Thanks for following through on that question. Although I believe it originated in a discussion you had with someone else, it's something of great interest to me too.
Mike gets the milk bones!Without having gone over all the product data with a fine tooth comb, it looks as if we have a means to "build tight ventilate right", whether that ventilation needs to be .1 ACH of 1.3 ACH to maintain a healthy environment.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
Hudson
I did a real quick (very simple) cost summary of insulated wall assembly. No windows no doors.
I don't have alot of time to spend on it so that's why it is simplistic.
Rich
Edit
Super Insulated Wall Cost Comparision (Simple) Wall Assembly only Framing, Sheathing and Insulation No Sheetrock
30' x 60' Structure No doors or windows 1800 SF floor space, 180LF of wall 8' walls and 1680 SF of Ext. Wall
Materials only no tax no labor cellulose at 1"= 3.5 R All walls 16" on center
Mooney wall 2x4 with 2x2 horz. furring and densepak R-18 $3,237 $1.99/SF
2x6 with FG batts 1/2" OSB and 1"XPS R-24.5 $3,775 $2.33/SF
Maine Builder Double 2x4 w/OSB Truss DensePak R-42.5 $4,483 $2.77/SF
12" I joist 1/2" OSB and Dense pak R-42.5 $5,961 $3.68/SF
ICF Walls 4" XPS w/ 8" concrete Liteforms R-28 $8,702 $5.37/SF
Modified Larson Truss ?? Riversong is going to have to provide that
I tried to put this together on excel and it looked great when I previewed, but when I came back at noon and looked at it, it was a mess. So I edited and retyped everything. The ICF prices are from 1 year ago.
Edited 3/28/2008 1:45 pm ET by cargin
Edited 3/28/2008 2:30 pm ET by cargin
You say "only sheathing and framing"- did you factor the cost of the insulation in as well? If not, the ICF and 2x6 wall with XPS are not a fair comparison because the foam provides some R value that you would otherwise have to get from insulation (cellulose?).Also, could you do a double 2x4 wall, the interior wall with single top plate?
Jon Blakemore RappahannockINC.com Fredericksburg, VA
Jon
I was in a hurry posting.
Yes it includes insulation.
Rich
Interesting comparison. Thanks for posting them.
Here's a couple more which would be my preferred methods: 9" I-joists on 24" centers with Mooney adaptation, and 2X8 on 24" center with Mooney.
What price per lin. ft. did you use for the I-joists?
Edited 3/28/2008 11:55 am by Hudson Valley Carpenter
Hudson
I was going to do a 24" comparision too. But i have a job and family.
Rich
But i have a job and family.
I'm glad that someone around here is being responsible and productive. It ain't me, that's for sure. LOL.
Hudson
My lumber yard gave a price of $1.80 LF.
Now it might be better if I when in with a plan and a specific # of LF.
Rich
Interesting numbers. Although, as they say, your actual mileage may vary,....the difference in material cost from lowest to highest non-ICF design is only about $2700, or around $1.50 per sq.ft. Even with the extra few days of labor that may be involved in assembly of any of these vs. conventional framing, it's easy to see why the total cost of the house shouldn't be but a few percent more.And what do the granite countertops, steam room, home theater, cathedral ceiling, "design elements," etc. run?
Dick
This was a simple calculation.
Extra ext. jambs for windows and extra deep door jambs and thresolds.
We're talking a 13" door jamb. Most of my door jambs any more are clad.
I have ordered one that depth once and I think it was 84 tall.
Rich
Mike
Can I join that club. LOL
Rich
Thanks for the additional photos and descriptions. They help me to visualize the process.
One thing I don't get...why is the roof being supported by those brackets? A photo of that detail would help too.
What material are the wall braces? What guage? What's their expected service life?
One thing I don't get...why is the roof being supported by those brackets?
What brackets? You mean those staging brackets that are hanging from (and clamped to) the wall assembly so that we can put on the roofing?
What material are the wall braces? What guage? What's their expected service life?
By wall braces, do you mean the let-in metal T-bracing? If so, Simpson makes them, they're 11'-4" long, and they're a standard lumber yard item:
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Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Makes sense now. Couldn't tell from the photos. Small screen, old eyes.
If you consider the very high conductivity of steel, the effect of nail penetration is may times worse than the same number of holes in the foam. And the cold steel tips also make great condenstion points.
That makes sense.
Now my question for you is why did you say that one should take care to nail in the studs to reduce this insulation degradation.
It would seem to me that you may want to nail away from the studs (integrity of the connection notwithstanding, just looking at it from a heat loss POV) to "spread out" the thermal bridging.
I guess that brings me to another question. From a pure heat loss POV, does it matter where your thermal bridges are with respect to each other? For instance, if one were to frame a wall with a 7" plate and double 2x4 studs, does it matter if the studs are in the same plane rather than staggered?
I know that by staggering the studs, you would avoid issues such as ghosting on the interior of the wall and other related thermal issues, but I'm thinking the BTU/HR heat loss is exactly the same regardless of where your studs are.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
It would seem to me that you may want to nail away from the studs (integrity of the connection notwithstanding, just looking at it from a heat loss POV) to "spread out" the thermal bridging.
I was actually wondering the same thing as I was posting that statement, and the only advantage perhaps to keeping the nails in the wood is to avoid the condensation points on the inside surface of the condensing plane (the foam).
And, I was thinking there might be fewer nails if they were limited to studs instead of random.
I guess that brings me to another question. From a pure heat loss POV, does it matter where your thermal bridges are with respect to each other? For instance, if one were to frame a wall with a 7" plate and double 2x4 studs, does it matter if the studs are in the same plane rather than staggered?
The as-built R-value for a 12" cellulose-filled double stud wall with:
in-line studs = R-43 (5.7% degradation)
staggered studs = R-43.6 (4.4% degradation)
With the 7" wall you describe (ignoring the bridging at the plate)
in-line studs = R-22.3 (16.1% degradation)
staggered studs = R-24.3 (8.6% degradation)
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
With the 7" wall you describe (ignoring the bridging at the plate)
* in-line studs = R-22.3 (16.1% degradation)
* staggered studs = R-24.3 (8.6% degradation)
Why is that? If you take a generic 96"x96"x7" wall assembly, you will have 64,512 in³. Fourteen 1.5"x3.5"x96" studs is 7,056 in³ leaving 57,456 in³ of insulation.
.109% of the wall is R-7 (assuming R-1 per inch of softwood)
.891% of the wall is R-26.6 (R-3.8/in. of cellulose)
I get a whole wall R-24.46. No matter where you have the studs, they're all in the wall. What am I missing?
Jon Blakemore RappahannockINC.com Fredericksburg, VA
For overall wall U (=1/R), get the sum U*A (or A/R) and divide it by total area "A". This can be done per foot of wall height, if top and bottom plates are being ignored.So, looking down at a cross section of wall, consider the various horizontal parallel paths from inside to outside, per 16" of wall width.In the inline stud case (two 2x4 studs butted together for 7" I guess), you have 1.5" width and 7" deep, U=1/7, U*A= 1.5/12/7 = 0.017857 BTU/deg F (per foot of wall height).For the 7" of insulation, width 14.5" and R=3.8/inch,
U*A= 14.5/12/(3.5*7) = 0.049320
The sum of U*A = 0.067177, and dividing by 16/12 sq.ft of wall area (per foot of wall height) gives overall U=0.05038, so R is the reciprocal or 19.848For the staggered stud wall, there would be three pieces per 16" of wall width. Two are 3.5" stud depth covered with 3.5" of insulation. U*A for each of these insulation-covered studs would be:
U*A = 1.5/12/(3.5 +3.5*3.8) = 0.007440
Then there would be (16 -1.5 -1.5) = 13 total inches of wall width with nothing but insulation. Its U*A = 13/12/(7*3.8) = 0.040727Sum of U*A then is 0.007440 *2 +0.040727 = 0.05561 and dividing by area:
Overall U= 0.05561/(16/12) = 0.04170, and R is 1/that = 23.977.Basically, it comes down to adding up the parallel heat losses (ignoring "fin effects" of lateral heat transfer in the vicinity of the studs within the insulation), then dividing by area to get the overall wall R needed that would be needed to get the same total heat loss (per degree, per unit wall area).To get more accurate, each of the above parallel heat paths ought to have added to them the roughly R=0.5 or more for the OSB outside, more for drywall inside, more for air film coefficients. Or, since these are applied uniformly to the inside and outside, you could just add the R of the layers to the whole wall R you calculate from the inside pieces.I'm assuming Riversong and I have both been typing furiously to see who gets his reply on the math up first.Edit: my whole wall R values don't agree. I gotta check my math and assumptions!2nd edit: To avoid confusion in mixing U in BTU/ft2/hr/degF and areas in square inches, calcs have been redone per sq.ft of wall area. But I think I may have the 7" wall description different. Anyway, the effect of staggering the studs is shown.Edited 3/27/2008 8:46 am ET by DickRussell
Edited 3/27/2008 9:23 am ET by DickRussell
While you can add up R-values through any cross-section, you can't proportion a wall system using R-values. You have to convert to U-values (1/R) to proportion heat flow through an assembly of different elements.
If framing is 16" on with 1½" thick studs, then the proportion of wood (excluding corners, window & door jacks, headers, etc) is 1.5/16 = 9.4%, and the proportion for insulation cavity is 14.5/16 = 90.6%.
Then multiply each percentage by the U-value of that cross-section and add the results. Convert again back to R and you've got the as-built R-value.
2x4 wall, 7" thick, inline studs (effectively 7" studs):
View Image
2x4 wall, 7" thick, staggered studs (8" o.c.) with thermal break (3.5" cellulose):
View Image
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/27/2008 10:59 am ET by Riversong
Your 2x6 wall with 1-1/2" strapping and 2" of foam give you a 9" wall thickness.Why not go with a Larsen truss or just frame two 2x4 walls with 2" of airspace? I would bet that you could frame the interior wall just as fast as applying the strapping. Whether or not you use sheathing on the outside, with no foam you've eliminated the nailbase issue.Something I really like about the double wall is you can increase the R value quite easily. If you want to add ~R8 and are willing to sacrifice a dozen or so SF, just frame the walls with 4" in between and you have more space for cellulose.I think Mike Smith expressed some concerns about denspacking a double wall but I believe Riversong does it with his Larsen truss wall. Maybe that's not an equal comparison, I don't know.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
Jon
I don't want to be redundtant, but Dick Russell posted about a Maine who builds a 12" wall with 2 2x4 spaced apart with OSB.
Then the wall cavities should denspak quite well.
http://forums.taunton.com/tp-breaktime/messages?msg=102383.25
I figured it would only take about 45 pc of 7/16" OSB ($315) to space the studs on an 1800SF home. (16" centers)
Here is the link to the builder's website with pics.
Rich
Edited 3/26/2008 11:15 pm ET by cargin
Thanks again Mike, for adding a bit of reality to my analytical overload. ;-)
Net wall is total wall
Gross wall area is total wall area. Net wall area is gross wall area minus doors and windows.
BTuH = Area x delta-T x 1/U
BTU/Hr. = Area x U x delta-T (not 1/U)
or = Area/R x delta-T
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
oh thanks...type too fast and it all gets garbledMike Smith Rhode Island : Design / Build / Repair / Restore
What is considered a healthy ACH? What do your houses do?
ASHRAE calls for a minimum of 0.25-0.35 ACH, though with all the formaldehyde in today's homes they are considering 0.50 ACH as a minimum standard.
Since I use mostly non-toxic materials and build for mostly non-toxic people, I aim for 0.25 ACH.
In my last house, because it had central heat and an owner who might not pay attention to careful operation, I direct-coupled the woodstove to a dedicated combustion air inlet and relied soley on the bathroom fans (Panasonic) for exhaust-only ventilation, with 24-hour programmable timers to comply with Energy Star standards.
In houses I've built that have only a woodstove (plus passive solar) for heat, I've relied on the woodstove as the primary exhaust "fan", close-coupling but not direct coupling to combustion air (a nearby register) so that the woodstove depressurizes the house and brings fresh air in through passive make-up air inlets.
I also rely on kitchen and bath exhaust fans to eliminate moisture at the source, and in one house I wired a dehumidistat in parallel to the bath fan to evacuate the house when RH levels rose (which is a good indication of inadequate air exchange).
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Robert
Thanks for the explaination.
I don't build houses just do remodeling. But I want to learn and I try to do the use the most energy efficient methods with the houses I work on.
Rich
All
Anybody know the ACH of a well built all ICF home?
I'll bet this has to be a concern in an ICF home as well.
Rich
.25 air changes /hour at 50 psi (blower door test) on page 3.
I don't know where the .01 was mentioned.
And on the same line of the chart in the referenced article, it gives the "0.01 nat" value. That notation is that the house is tight, naturally, to 1 air change in 100 hours. It says that the structure leaks 1 air change in 4 hours if you over pressure the structure by half an atmosphere (50 Pa).
So, the air in this structure only "freshens" every fourth day or so, unless some form of powered HRV is installed. HRV means you are introducing outside air into the structure so that the occupants can breathe. Now, that air is "tempered" by the HRV, but that's still introducing "load" on the heating system. it also, by definition, increases energy consumption since a fan has to be run to move the air in and out of the structure.
Houses are systems, you can't jsut max out one thing and declare victory, which is something that bothers me about the super-insulation crowd.Occupational hazard of my occupation not being around (sorry Bubba)
in the homes shown in the article, my computer alone would probably be enough to keep a room comfortable.
The "energy to heat" quoted in the article still nags at me. Because you are likely right, your computer probably whould heat the structure. But how much energy will it take to circulate the air inside?
No mention was made on how many ACH the houses had (or what mechanism caused them). I'm (desparately) trying to not imagine what a shut-up for 12-14 weeks' worth of winter heated only with a hair dryer smells like <g> . . .Occupational hazard of my occupation not being around (sorry Bubba)
Robert
My reaction: ugly houses
I'm wearing my Complaint Free purple bracelet so i am not at liberty to comment on the aesthetics.
I will say you build a better looking house then these.
Rich
One Word:Fugly.Steve
Fugly.
Maybe they look better from the other side, with those nice clerestory windows?
View Image
At least this has some pizzaz!
View Image
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/18/2008 8:15 pm ET by Riversong
most concept houses suffer from poor aesthetic design
but i do like a lot of the conceptsthe i-joists are cool ... they'd have a very low thermal bridge effect
i can buy damaged i-joists from lumber yards
substitute cells for fiberglass
let the electrician wire them conventionally...
i'd build with our usual technique
rimboard for shoe & plate
ply sheathing
frame teh wall on the deck & erect
i'd do insulweb on the interior and use 1x3 furring horizontally to reinforce the insulwebthe frost protected slab would be good
elec. resistance heaters
hrvthe windows are still the achilles heelMike Smith Rhode Island : Design / Build / Repair / Restore
the windows are still the achilles heel
Forget windows if you're going for net zero. Lots of LED lights and a solar-powered HRV.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
net zero is net zero........it usually adds up to ugly ....
this is a home .... not a lab
homes have windows.... homes are lived in 12 months ... not just the 4 or 5 months of heating seasonMike Smith Rhode Island : Design / Build / Repair / Restore
Good morning Robert
I am interested in your honest appraisal of the health benefits of living in a SIP or an ICF home.
Putting embodied energy aside and trying to stay with discussions focused on techinques.
What are the health hazards of living in a home full of OSB?
What are the health hazards of living in a home full of EPS?
We had friends build a new house (lots of OSB and new carpet, very conventional). There 17 year old daughter got very sick with fibermyalga type stuff (weird kind of stuff, hard to diagnose). Our local health food guru (I love her dearly, but she is a food zealot) thinks it was the new house that see was reacting to.
You know I am not trying to start a flame war. I'm just trying to tap into your knowledge base and have a discussion about materials and techniques.
Thanks
Rich
What are the health hazards of living in a home full of OSB?
What are the health hazards of living in a home full of EPS?
Good questions, not often enough considered. Let's start with OSB.
from http://www.encyclopedia.com/doc/1G1-91398458.html
OSB is the largest growth segment of this transition with over sixty new mills in the US and Canada, most built in the last decade. OSB production has increased nearly thirty-fold since 1980 and overtook plywood in 2001 as the leading panel board for construction According to the Structural Board Association, OSB will have a sixty percent market share by 2004.
The manufacturers and trade groups rally around the "environmentally friendly" nature of OSB. Claims are made that OSB utilizes waste wood, young trees, and trees unsuitable for other purposes, and can come from plantations of fast growing hybrids or genetically engineered, cloned "frankentrees". The reality is that the vast majority of OSB production is responsible for clearcutting remaining native forests of the Southeastern US, as well as robbing mature public and private forest in Canada, Chile, and nearly everywhere they have established plants. Due to their ability to use even small trees and utilize limbs and `waste' wood in generating some of their energy demands, the clearcutting is becoming more prevalent and severe, leaving virtual deserts where forests once stood. Despite claims of sustainability, virtually none of the industry's cutting practices have ever been shown to be remotely sustainable.
The first community health impacts of OSB manifest themselves in polluted waters downstream from clear cuts, contributions to global warming from deforestation, and increasing flood damages. Additional assaults to communities near OSB clear cuts include adverse health effects from applications of toxic herbicides and fertilizers used in replacement plantations. Over a quarter of the South's remaining native forests are slated to be destroyed and converted to chemically intensive fiber farms by 2040, or far earlier by some estimates.
The resulting increase in industrial scale clearcutting is adversely affecting many species of plants, animals, and birds that depend on mature forested landscapes. Increased sedimentation and erosion from logging is damaging water quality, impacting aquatic species as well as drinking supplies.
OSB HEALTH DANGERS
Because we can no longer find enough mature forests that can be milled to meet demands, the building industry is focused on gluing together chopped up pieces of remaining and young forests using urea-formldehyde (U-F) phenol formaldehyde (P-F) and methylene-diisocyanate (MDI).
Workers are now facing far more toxic workplaces in manufacture and building trades, communities are dealing with toxic releases of these chemical into their air, land and water, and consumers are seeing elevated levels of toxins within their homes. While MDI is far more toxic acutely to workers in manufacturing, the more widely used formadehyde based building products out-gas into homes of consumers for years. U-F is an order of magnitude more potent than P-F.
Cyanide-based MDI is a suspected human carcinogen [5], and isocyanates have also been shown to cause respiratory distress and death in humans and cancers in lab animals. (An MDI release in Bhopal, India killed 2000 people.)
According to the EPA, newer homes may have greater than three times the concentration of formaldehyde in ambient air than older homes. It is not uncommon to have formaldehyde levels in homes far higher than the current national standard for protecting public health.
There is concern among some about links of the increasing reliance on chemically engineered building products to to the epidemic increase in childhood asthma and dramatic increase in adults in the last two decades, as well as a variety of other suspected health effects.
The Precautionary Prinicple states that, until we know that a product is safe, better to avoid its use.
from http://www.builtgreen.org/checklist/guide.aspx?ChecklistID=81
Formaldehyde is normally present at low levels, usually less than 0.06 ppm (parts per million), in both outdoor and indoor air. When present in the air at levels at or above 0.1 ppm, acute health effects can occur including watery eyes; burning sensations in the eyes, nose and throat; nausea; coughing; chest tightness; wheezing; skin rashes; and other irritating effects. Sensitive people can experience symptoms at levels below 0.1 ppm. The World Health Organization recommends that exposure should not exceed 0.05 ppm.
Edited 3/19/2008 12:49 pm ET by Riversong
What are the health hazards of living in a home full of EPS?
As for polystyrene, whether extruded (XPS) or expanded (EPS), the primary impacts are environmental, which has a substantical secondary impact on human health.
“in the categories of energy consumption, greenhouse gas effect, and total environmental effect, EPS’s environmental impacts were second highest, behind aluminum.”
from http://en.wikipedia.org/wiki/Polystyrene
<!----><!----><!---->
Polystyrene is an aromatic polymer made from the aromatic monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum by the chemical industry. Polystyrene is a thermoplastic substance, normally existing in solid state at room temperature, but melting if heated (for molding or extrusion), and becoming solid again when cooling off.
<!----><!---->
Polystyrene's most common use is as expanded polystyrene (EPS). Expanded polystyrene is produced from a mixture of about 90-95% polystyrene and 5-10% gaseous blowing agent, most commonly pentane or carbon dioxide. The solid plastic is expanded into a foam through the use of heat, usually steam.
<!----><!---->
Extruded polystyrene (XPS), which is different from expanded polystyrene (EPS), is commonly known by the trade name Styrofoam. The voids filled with trapped air give it low thermal conductivity. This makes it ideal as a construction material and it is therefore sometimes used in structural insulated panel building systems.
<!----><!---->
Expanded polystyrene used to contain CFCs, but other, more environmentally-safe blowing agents are now used. Because it is an aromatic hydrocarbon, it burns with an orange-yellow flame, giving off soot, as opposed to non-aromatic hydrocarbon polymers such as polyethylene, which burn with a light yellow flame (often with a blue tinge) and no soot.
<!----><!---->
Health Effects<!----><!---->
The health effects caused by consuming polystyrene when it migrates from food containers (primarily from a leaching caused by heat exchange) into food is under serious investigation. Benzene, a material used in the production of polystyrene, is a known human carcinogen.
<!----><!---->
The EPA claims
<!----><!---->
"Acute (short-term) exposure to styrene in humans results in mucous membrane and eye irritation, and gastrointestinal effects. Chronic (long-term) exposure to styrene in humans results in effects on the central nervous system (CNS), such as headache, fatigue, weakness, and depression, CSN dysfunction, hearing loss, and peripheral neuropathy. Human studies are inconclusive on the reproductive and developmental effects of styrene; several studies did not report an increase in developmental effects in women who worked in the plastics industry, while an increased frequency of spontaneous abortions and decreased frequency of births were reported in another study. Several epidemiologic studies suggest there may be an association between styrene exposure and an increased risk of leukemia and lymphoma. However, the evidence is inconclusive due to confounding factors. EPA has not given a formal carcinogen classification to styrene."
<!----><!---->
<!----><!---->
Polystyrene is classified according to DIN4102 as a "B3" product, meaning highly flammable or "easily ignited". Consequently, though it is an efficient insulator at low temperatures, it is prohibited from being used in any exposed installations in building construction as long the material is not flame retarded e.g. with hexabromocyclododecane. It must be concealed behind drywall, sheet metal or concrete. Foamed plastic materials have been accidentally ignited and caused huge fires and losses. Examples include the Düsseldorf International Airport, the Channel tunnel, where it was inside a railcar and caught on fire, and the Browns Ferry Nuclear Power Plant, where fire reached through a fire retardant, reached the foamed plastic underneath inside a firestop that had not been tested and certified in accordance with the final installation.
<!----><!---->
In addition to fire hazard, substances that contain acetone (such as most aerosol paint sprays), and cyanoacrylate glues can dissolve polystyrene.
<!----><!---->
Expanded polystyrene is not easily recyclable because of its light weight and low scrap value. It is generally not accepted in curbside programs. Expanded polystyrene foam takes a very long time to decompose in the environment and has been documented to cause starvation in birds and other marine wildlife. According to the California Coastal Commission, it is a principal component of marine debris. A CIWMB (California Integrated Waste Management Board) Report finds that “in the categories of energy consumption, greenhouse gas effect, and total environmental effect, EPS’s environmental impacts were second highest, behind aluminum.”
<!----><!---->
<!----><!---->
Hot Knife Cutting:<!----><!---->
Products Evolved When Subjected to Heat or Combustion: Toxic levels of carbon monoxide, carbon dioxide, irritating aldehydes and ketones.
Edited 3/19/2008 1:17 pm ET by Riversong
Robert
Since I don't like it when OP don't answer responses, let me say I don't have time to read your or all the other posts right now.
We are going to visit Tim tonight. So i am interested just out of the house tonight.
Rich
Robert
Thanks for taking the time to reply so fully.
Lots of reading.
Rich
Mike
What I see is the following
- Balloon framing, thereby putting your floor joists inside the thermal envelope. I would like the let in 1x4 but it may weaken the I-joist.
- A thermal bridge at the top plate, the bottom plate and the I-joist ( I think could live with that) You would probably have a thermal bridge where the rafter is in contact with the sheetrock ceiling and then the soffit. Even the Larson truss has that. You could avoid that bridge by using EPS on the ceiling and furrring out the ceiling with 2x4 and running all your wiring inside of the EPS
- Use conventional air sealing like Riversong does with his plates and sheetrock
- This method would speed the wall framing
- Wire the house conventionally like you said. You could use sealed boxes and a little air flow would be a good thing.
- I would like to see a house with more thermal mass (like a ICF)
- Darn it it's exciting to see a house that could be built with a heating load of a couple of base board heaters.
- I would avoid the OSB thing on the inside walls like the article mentioned.
- I am not sure why you would still do the 1x3 furring strip as in your post. Would it be just to hold the insul-web in? Or do you want to run wiring in the chase?
- I am intrigued by Robert's concept of no vapor barrier and letting the vapor absorbing ability of the cellulose regulate the humidity.
Rich
i would frame the walls 24" oc with the I-joists... and with 11 7/8 walls, the pressure on the dens-pak cells would create problems with pushing the envelope of the Insulweb
also , by furring the walls horizontally with 1x3 @ 16" oc i get a couple things :
easier to hang the gypsum
i can substitute 3/4" ply anyplace i want blocking ( like cabinets , window trim, insulated headers ... or even electrical devices let-in to the 3/4 ply )
the furring reinforces the Insul-web
and .... IF it's a two story.. i wouldn't go balloon frame
we always block our joist area... it winds up being better insulated than the wall area
so i would still do tilt-up platform framing... only now the walls will be 12" thick with a rimboard shoe & plate... 1/2" cdx sheathingMike Smith Rhode Island : Design / Build / Repair / Restore
we always block our joist area... it winds up being better insulated than the wall area
Mike,
I don't understand what you mean by this. I remember your blowing the rim joist bay with cells in the past houses you've posted, but I don't remember how your detail achieves more insulation than the wall cavity. Can you elaborate?
Jon Blakemore RappahannockINC.com Fredericksburg, VA
the joist bays are say 9.5" tall... and on the eave walls we block in about 16"
on the gable ends we fill the whole outer bay so typically the cells are say 14" thick
instead of the 5" thickness in the walls
there is a little more thermal bridging here than other locations, but it's still minimal
if it were an I-joist wall with stacked framing ( the ceiling / floor joists would have to stack if all we're using is a rim-board for a top plate ) then the thermal bridging will be even lessMike Smith Rhode Island : Design / Build / Repair / Restore
Mike
Thanks for the discussion.
Fun to think about and talk about.
You are probalby right about the 1x3s. Good place for blocking. I saw the Maine builder in Dick's link ran his wiring in the 1x3 chase way.
Rich
I would get nervous about the wiring being that close to the surface. Would codes even allow that?Steve
Steve
Don't know.
We don't have code enforcement here.
Sorry I can't be more helpful.
Rich
i was only planning on mounting the devices in the 3/4" planethe wiring would still be in the web of the I-joists... just like it is drilled in the middle of the 2x4's noweven in Mooney wall, the wiring is still in the 2x4.... only the devices are in the blockingany time we get within 1.5 inches of the face of stud we have to plate it with screw/nail stopsMike Smith Rhode Island : Design / Build / Repair / Restore
I wonder how the BI would accept I joists installed 90 degrees from normal? Are they approved? On another note,the excellent thread you had last year on your house build there was a law suit amongst the property owners . What was the outcome, or, knowing attorneys it aint finished.
i bet i could get him to approve them or have an engineer approve the wall
my customer won the lawsuit... all it cost him was $100,000 in legal & court fees.....
so, let's be careful out thereMike Smith Rhode Island : Design / Build / Repair / Restore
$100k...I bet you could have done one nice front porch for $100k.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
yes...... all the legal money came out of the design....Mike Smith Rhode Island : Design / Build / Repair / Restore
the i-joists are cool ... they'd have a very low thermal bridge effect
Now that I've read this thread and some of the linked articles I'm beginning to get interested in using I-joists.
One question that arises about deep walls; how do you get the house assessed on it's actual living space? I ask because I've had that problem in the past when they insisted on using exterior dimensions only.
I don't like paying taxes on non-existent living space, year after year.
the frost protected slab would be good
I liked the description of that but what are it's limitations? Does it have to be on bedrock in order to build two stories above?
the i-joists are cool ... they'd have a very low thermal bridge effect
Be careful of using a manufactured structure in a manner not consistent with its intended use.
I don't like paying taxes on non-existent living space, year after year.
If your fuel savings don't over-compensate for the additional property taxes, then you've done something wrong.
the frost protected slab would be good
I liked the description of that but what are it's limitations? Does it have to be on bedrock in order to build two stories above?
No limitations. They're used for high-rise buildings in Scandinavia. Like any foundation, they have to have sufficient bearing surface on appropriate soils for the intended loads.
Edit: with the possible exception of hurricane zones, since they are not deeply anchored in the earth.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/20/2008 4:26 pm ET by Riversong
Be careful of using a manufactured structure in a manner not consistent with its intended use.
Whatever my architect and I come up with will have to be engineered and pass code before permits are authorized.
If your fuel savings don't over-compensate for the additional property taxes, then you've done something wrong.
If you don't have some practical advise on the question, why reply with a presumption which is not relevant?
.
If your fuel savings don't over-compensate for the additional property taxes, then you've done something wrong.
If you don't have some practical advise on the question, why reply with a presumption which is not relevant?
There is no practical advice - you pay property taxes on the exterior footprint.
Above statement was not a "presumption", it was a syllogism - a simple statement of logic.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/20/2008 8:49 pm ET by Riversong
There is no practical advice - you pay property taxes on the exterior footprint.
That's been decided by whom? The U.S. Supreme Court? Even then, it would be open to appeal.
Above statement was not a "presumption", it was a syllogism - a simple statement of logic.
Yes, it's a presumption. Unless, that is, you can convince my tax collector to take firewood in place of U.S. currency.
Hi,"the i-joists are cool ... they'd have a very low thermal bridge effect""Be careful of using a manufactured structure in a manner not consistent with its intended use."They are approved and promoted for this application in Europe.http://www.builditsolar.com/Projects/SolarHomes/constructionps.htm#IStudsSeems like a good idea -- wonder why they have not caught on here?Gary
Two thoughts:1. Is there a way to monitor when the air needs to be changed? Kind of like a humidistat, except instead of monitoring the relative humidity this instrument would measure off-gassing, allergens, moisture, etc. This could provide active ventilation when needed (open a window, turn on the bath exhaust fan and open the damper on the airlet, etc.).2. My second thought is how harmful can "stale" air be in the event of a power failure? I don't have a generator at my house- if the power goes off, we get cold (and out come the sweaters and blankets). Is it really a good idea to shun HRV's because they require a power source which, in my experience, is about 99.5% reliable? If the power were to go off the air becomes toxic, can't we just open a window?
Jon Blakemore RappahannockINC.com Fredericksburg, VA
Is it really a good idea to shun HRV's because they require a power source which, in my experience, is about 99.5% reliable? If the power were to go off the air becomes toxic, can't we just open a window?
I don't have statistics, but in rural areas that experience lots of winter storms, power outages are relatively common.
But isn't there something inconsistent with relying on a high-tech ventilation system and then having to open a window when it isn't functioning?
Wouldn't it make more sense to use a low-tech, and much more reliable, system that requires no energy input?
Don't forget to deduct from the heating fuel savings the electrical consumption of an HRV when calculating payback period.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
You make some good points. I guess one has to determine how much they trust their POCO and make decisions accordingly.Have you ever installed an HRV in one of your houses, or has there never been an occasion when you felt it was worth the trade offs?
Jon Blakemore RappahannockINC.com Fredericksburg, VA
They are approved and promoted for this application in Europe.
Seems like a good idea -- wonder why they have not caught on here?
Lovely house:
View Image
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Looks like a bomb shelter.Steve
i'd do insulweb on the interior and use 1x3 furring horizontally to reinforce the insulweb
Mike,
Is it your experience that insulweb needs a box pattern of support in order to hold it's shape?
Also, I was hoping that you might have some comments on the later posts by me and Jon B. in this thread. If you don't like any of those ideas, be ruthless. Take out your machete and cut 'em up.
I'm getting serious about maxing out the insulation using deeper/thicker walls because it seems to have so many benefits.
For example; if super insulation makes electric heat feasible, that alone would save enough on the budget to pay for the additional materials and labor needed to achieve max R-value.
It's hard to know where fuel costs are going but it seems likely that electricity will become relatively cheaper as time goes by.
hmmmm..... our house is a double wall house ( 1984 ) 2x4 exterior bearing wall... 1" air space..... 2x3 interior wall...... ( cells exterior with a vapor barrier... then fiberglass batts on the interior.... it was ok in it's day.. but laugable today
double walls seem good... but... i don't know how you could dens-pak them very easily, they cost more for labor.... and you still have the problem of blocking for cabinets, towel bars, window & door trim
i think i like a 2x8 wall... 24" oc... 1/2" sheathing
the shoe & plate can be 1/2" ply or osb ripped to 7 1/4
still do tilt-up
and i guess i'd stick with the 2x2 mooney...
i'm assuming , based on past observations, that we can stretch , staple and glue the Insulweb and even though the bay is now 9 3/4 deep... the pressure will not bulge the walls any more than it does now... and bulges can still be pushed back with the palm of your hand
so... what...... 10% ( a little less with 24" oc ) of the wall will be R-9
and 90% of the wall will be ( 3.7 x 9.75" ) = R-36
average total wall ( without adjusting for air layers, sheathing & drywall = R - 33
here's a link for a discussion between "super wall" & sips
http://www.greenbuildingtalk.com/Forums/tabid/53/forumid/5/postid/30817/view/topic/Default.aspx
at the openings.. i'd do a modified wall.. the studs would be the 2x8, but the jacks & headers would be 2x4 ( insulated box headers ) ... then i'd use a 1/2" plywood sleeve for the rough opening, flush from back of sheathing to face of Mooney... this would allow me more insulation at these areas
truss roof @ 24" oc ... stacked over the studs
so.... all the above is a compromise..... a "super wall" that is 9 3/4 " from face of sheathing to face of gypsum... with an r-value of R-33 for total wall
fairly easy to build, good interior blocking, easy for the board hangers, all dens-pak cells... maybe some EPS foam in the headers & corners, maybe not
i don't want foam on the exterior of my foundation... so if it is not a full basement, then my sill will be a PT 4x8... so i can get a minimum of 4" EPS at the edge & under the slab
if it's a full basement , then i'll have an insulated band joist area , EPS foam on the inside and an insulated stud wall inside that
attic will be R-60, and windows R-3 with an exterior storm to bring them to R-4Mike Smith Rhode Island : Design / Build / Repair / Restore
Mike,
I'm following your reasoning with great interest. I agree with you about the 2X8on24"C making more sense, except that my lower back keeps protesting about lifting the walls. ;-)
That brings up a question about raising walls with 1/2" ply top plate.
How do you join the 8' lengths of ply? And how does that work out for strength on longer walls? Same as standard double top plate?
What would be your preferred method for raising a long 2X8 wall with ply shoe and plate?
One problem with the double 2X4 wall is having to put in blocking to nail off the inner one, above and below the end walls. They also need to be tied together on top, every so often.
So, when considering labor alone, between framing one 2X8 Smith-Mooney wall or the double 2X4, the 2X8 Smith-Mooney wall trumps the double wall easily.
I'm glad to hear that you're pretty certain that the deeper cell pack wouldn't cause a problem.
I'm not quite visualising how the sleeved openings would work for nailing but that's not a big deal right now. The boxed headers definitely make sense, if the engineer will to go along with that on longer spans.
My new home will be three stories on a hillside, graded to make maximum use of fill as a terrace at the lowest level. So the lowest story has to be masonry walls per code, even though it will probably be all above finished grade.
Do you have any ideas/suggestions for how to make the best of that situation?
"windows R-3 with an exterior storm to bring them to R-4"
So...no comment on my SIP-type shutter idea? ;-) That's OK. I think it's worth an experiment or two, even though the mechanical part of the concept has some problems.
Mike, thanks a bunch for replying and giving me the benefit of your experience.
I've built and lived in a couple of my own concept homes, back in the 60's when there weren't any forums for discussing and sharing ideas and experiences. Both of those places would've been better if I'd had the kind of help that you're so gracious to offer here.
we lift almost all our walls with Proctors
i'd tack a temporary 2x4 plate on the bottom ( inside top) of the wall to fasten my Proctor hooks to, and give the wall some strength until it's vertical
a 2x8 wall is child's play for a set of Proctors
it's interesting the rest of the discussion about HRV's and air changes
i'd guess that part of my compromise is influenced by that also....
i'm thinking that my two ( for better air circulation ) small window A/C's and their sleeves will be part of the HRV set-up
i think what we are looking for is a good neutral house for Spring & Fall, easy to heat , easy to cool... with good healthy air... it;s hard to design a horse like that without it winding up looking like a camel
Mike Smith Rhode Island : Design / Build / Repair / Restore
Edited 3/24/2008 2:05 pm ET by MikeSmith
Thanks for the advice about Proctors. Never used 'em so that'll be a new adventure too.
This building site should yield a lot of good photos. That'll be one of them, raising the big wall on the top floor with a view of the Hudson Valley.
I haven't gotten into the HRV part of the equation yet. Or the HVAC part, for that matter.
My site is inland, at 1200' above sea level, ESE exposure, about the same latitude as where you are. I plan on shading all the glass during the hot months so I don't expect to need AC, just good flow, bro.
hudson valley.... boy.... that locks it in
i spent some time around Poughkipsee.. poking around the New haven RR bridge
and my last duty station in '69 was West Point.. so i do know that part of the Hudson
which part are you talking ?Mike Smith Rhode Island : Design / Build / Repair / Restore
Western Orange Co, not far from the NJ border.
I know that bridge pretty well, from several vantage points. What do you mean, poking around?
My first union carpentry job was at West Point, in 1970. Stoney Lonesome housing. I learned a lot of basic framing techniques there. In '69 Stoney Lonesome was probably one of the places where you enlisted guys went to party.
I worked on several other jobs there, over the years.
Mike,
Do you have a program for heat loss calculations? Got link?
Peter
no..... i just do rough calcs nowadays... there are lots of freeware calc programs on lineand .... most of the time it isn't neccessary to be to anal sizing equipment ( heating & cooling ) is what i use it for mostly
and doing comparisons.. so , if i use the same assumptions, the comparisons are pretty validMike Smith Rhode Island : Design / Build / Repair / Restore
i just do rough calcs nowadays
Fine by me but I'm not acquainted with how it's calculated. Would you mind sharing your formula?
Edited 3/25/2008 3:41 am by Hudson Valley Carpenter
For one heat loss program you might download the RESCheck program. It's free. Just Google on it; easy to find. There may be a NY-specific version of it. NH has one; I've used it. I get a result not very different from using a spreadsheet I put together earlier to add up the heat losses from each part of the envelope. That's all RESCheck is doing.Basically, you input the descriptions of walls, even parts of walls, basement, attic floor, types of windows with their U-factors (on the sticker, also available in window mfg catalogs). As you go along, entering the bits and pieces, you get a running tally of U*A for the structure. Then heat loss at any moment is U*A*(temperature difference, inside to outside). I can't say from memory if it handles air leakage also. If not, that's easy enough to add in manually.The nice thing about any of these programs is that you can easily change one component and see its impact on the overall heat loss, to see what's worth doing. But a whole bunch of little things may be worth doing. As my father used to say (in banking): "It all adds up."
Edited 3/25/2008 8:03 am ET by DickRussell
Thanks Dick, I'll check that out. Sounds simple enough for someone like me.
Doing math is "better than a poke in the eye with a sharp stick" but not by much.
:-)
Would you mind sharing your formula?
It's really pretty simple, but the devil's in the details (such as using as-built R-values rather than theoretical and real infiltration rates rather than assumed).
View Image
You calculate the net area of each element of the thermal envelope (for walls, don't forget to deduct for windows and doors), divide area of each by its R-value to get the heat loss coefficient (HLC). Calculate HLC for infiltration losses (air has a specific heat of 0.0182 btu/cf) by multiplying the specific heat of air by the total house volume times the percentage hourly air change rate. Then add up all HLC to get total HLC, which is BTUs per hour per degree delta-T.
Since we must design heat a heat source for the design minimum temperature (DMT), calculate maximum hourly heat loss by multiplying total HLC times maximum delta-T (Tin - DMT). Tin is assumed to be 65°, unless you plan to set the thermostat otherwise.
If you want to calculate annual heating season heat load, multiply total HLC times 24 hours times your local degree-days (HLC x 24 x DD).
This formula, however, is for a vacant house. If there are to be people living in the house, then you must account for human and utility heat gains (approx. 800 btu/hr for each occupant). This changes the balance point temperature (outside temp at which supplemental heat is needed), and effectively reduces the annual DD.
Then there are passive solar gains to take into account. But now we're getting beyond simple and you'll have to take one of my classes to get the whole enchillada.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/25/2008 10:42 am ET by Riversong
Under Air Infiltration, what's that 0.0182 represent? For your volume (a large house, 4200 sqft, 8 ft ceilings) and 0.25 ACH, I can calculate your 152 BTU/hr/degF almost exactly (using Cp=0.24 BTU/lb/degF, MW=29.0, density 0.075 lb/cuft). But I can't figure what the 0.0182 is supposed to be.For others, that HLC (Heat Loss Coefficient) is what RESCheck would call U*A or just UA. As in Robert's table, units are BTU/hr per deg Fahrenheit temperature difference. At 70 F inside, zero outside, dT is 70, and U*A*dT = 402 *70 = 28,140 BTU/hr.
Under Air Infiltration, what's that 0.0182 represent?
Perhaps you read my post before I finished editing it to add the explanation.
0.0182 btu/cf is the specific heat of air, or the volume of heat that each cubic foot of air contains for each farenheit degree of temperature.
Since the heat loss coefficient we're trying to calculate is in BTU/HR*F°, and we know the house air volume in cubic feet, then we want to start with units that match the intended result, such as the above specific heat of air.
[I revised 102383.131 above to correct the house volume]
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/25/2008 10:44 am ET by Riversong
To get as-built R-values of assemblies, you have to convert to U-value (1/R) and average proportionally to relative amount of envelope of thermal bridging.
For windows, make sure you use whole unit R or U values (not center of glass), and for doors deduct any glass area and treat that as a window.
Building Assembly R-Value Averaging
Wall Assembly R-Value<!----><!----><!---->
Component R-value<!----><!---->
1. inside air film 0.68<!----><!---->
2. 1/2" drywall 0.45 <!----><!---->
3. 3 1/2" fiberglass batt 11.00<!----><!---->
4. plywood sheathing 0.63<!----><!---->
5. siding - wood bevel 0.80<!----><!---->
6. wall - outside air film 0.17<!----><!---->
Total Wall R-Value 13.73<!----><!---->
Total Wall U-Value 0.073<!----><!---->
% of Wall Area (14.5”/16”) 90%<!----><!---->
<!----><!---->
Wall Assembly R-Value<!----><!---->
Component R-value<!----><!---->
1. inside air film 0.68<!----><!---->
2. 1/2" drywall 0.45 <!----><!---->
3. 2x4 stud 5.25<!----><!---->
4. plywood sheathing 0.63<!----><!---->
5. siding - wood bevel 0.80<!----><!---->
6. wall - outside air film 0.17<!----><!---->
Total Wall R-Value 7.98<!----><!---->
Total Wall U-Value 0.125<!----><!---->
% of Wall Area (1.5”/16”) 10%<!----><!---->
(0.073 x .90) + (0.125 x .10) = 0.078 As-Built U-Value1/.078 = 12.79 As-Built R-Value
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/25/2008 12:10 pm ET by Riversong
Thanks for taking the time to put that together and explain it.
Riversong post from last Spring
It's really pretty simple, but the devil's in the details (such as using as-built R-values rather than theoretical and real infiltration rates rather than assumed).
View Image
You calculate the net area of each element of the thermal envelope (for walls, don't forget to deduct for windows and doors), divide area of each by its R-value to get the heat loss coefficient (HLC). Calculate HLC for infiltration losses (air has a specific heat of 0.0182 btu/cf) by multiplying the specific heat of air by the total house volume times the percentage hourly air change rate. Then add up all HLC to get total HLC, which is BTUs per hour per degree delta-T.
Since we must design heat a heat source for the design minimum temperature (DMT), calculate maximum hourly heat loss by multiplying total HLC times maximum delta-T (Tin - DMT). Tin is assumed to be 65°, unless you plan to set the thermostat otherwise.
If you want to calculate annual heating season heat load, multiply total HLC times 24 hours times your local degree-days (HLC x 24 x DD).
This formula, however, is for a vacant house. If there are to be people living in the house, then you must account for human and utility heat gains (approx. 800 btu/hr for each occupant). This changes the balance point temperature (outside temp at which supplemental heat is needed), and effectively reduces the annual DD.
Then there are passive solar gains to take into account. But now we're getting beyond simple and you'll have to take one of my classes to get the whole enchillada.
Hey Riversong,
I have found your method to be very useful....thanks for posting it.
Can't afford to go out for enchiladas right now...how about a taste of passive solar gain ciphering... maybe a few free solar "nachos"?
Can't afford to go out for enchiladas right now...how about a taste of passive solar gain ciphering... maybe a few free solar "nachos"?
You don't have any sun in north Texas, do you? ;-)
Your Personal Quote:<!----><!----><!---->
"Keep the rain out.Keep the outside air out.Keep the inside air in and let the moisture out in both directions" per Lstiburek
Says nothing about letting the sun in - or keeping it out, for that matter.
Nachos: First look up the solar availability (BTU/day) for your area, then evaluate your site for solar shading and house orientation. Check your windows for SHGC.
<!----> <!---->
Passive solar building design:
<!----><!---->
Window Orientation degrees from true south % sunshine (vertical glazing)<!----><!---->
S 0 100<!----><!---->
SSE, SSW 22.5 91<!----><!---->
SE, SW 45 70<!----><!---->
ESE, WSW 67.5 45<!----><!---->
E, W 90 25<!----><!---->
<!----> <!---->
Percent of Noontime Radiation in December<!----><!---->
latitude solar noon 11:00/13:00 10:00/14:00 09:00/15:00 08:00/16:00<!----><!---->
36N 100% 96% 85% 65% 30%<!----><!---->
40N 100% 96% 83% 60% 20%<!----><!---->
44N 100% 95% 80% 54% 06%<!----><!---->
48N 100% 94% 77% 43% 00%<!----><!---->
<!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!---->SOLAR SHADING COEFICIENT<!----><!---->
•deciduous trees (winter) 10-50%<!----><!---->
•deciduous trees (summer) 90%<!----><!---->
•evergreen trees 90%<!----><!---->
<!----> <!---->
SOLAR COLLECTOR EFFICIENCY<!----><!---->
•double-glazed windows 50%<!----><!---->
•dgw with R-4 shade 60%<!----><!---->
•thermo-siphon air panel (TAP) 34%<!----><!---->
•TAP with fan 40%<!----><!---->
•greenhouse/sunspace 20%<!----><!---->
•sunspace with fan 35%<!----><!---->
•flat-plate collector with fan 40%<!----><!---->
SOLAR GAIN<!----><!---->
Available Insolation x Orientation Factor x Shading Coefficient = Insolation Factor<!----><!---->
BTU/SF*HR x % effectiveness x 1 - % shading = BTU/SF*HR<!----><!---->
<!----> <!---->
<!----> <!---->
Insolation Factor x Collector Efficiency x Area = Net Solar Gain<!----><!---->
BTU/SF*HR x % efficiency x SF = BTU/HR<!----><!---->
<!----> <!---->
* to include E & W glazing, use 30% orientation factor (25% plus additional reflection)<!----><!---->
SOLAR GLAZING RATIO (of floor area)<!----><!---->
Normal Home: 12% glazing divided equally all sides (3% S)<!----><!---->
Sun-Tempered: 5-7% South glazing - no additional mass<!----><!---->
Passive Solar: 7-12% South glazing - diurnal thermal mass<!----><!---->
<!----> <!---->
Solar Contribution: the percentage of a building’s total heat load that is supplied by the sun.<!----><!---->
Solar Savings Fraction (SSF): the percentage of energy saved by using solar energy to heat a building, compared to a non-solar building with similar thermal characteristics.<!----><!---->
<!----> <!---->
30% SSF - daytime gain = nighttime loss <!----><!---->
30-70% SSF - diurnal thermal storage required<!----><!---->
> 70% SSF - 3-4 day thermal storage required
THERMAL MASS PROPERTIES<!----><!---->
<!----><!---->
High Density - The more dense the material (ie the less trapped air) the higher its thermal mass. <!----><!---->
Good Thermal Conductivity - The material must allow heat to flow through it. But if conductivity is too high (eg. steel) energy is absorbed and given off too quickly to create the lag effect required for diurnal moderation.<!----><!---->
Low Reflectivity - Dark, matt or textured surfaces absorb and re-radiate more energy than light, smooth, reflective surfaces. (If there is considerable thermal mass in the walls, a more reflective floor will distribute heat to the walls).<!----><!---->
<!----> <!---->
<!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!----><!---->RULES OF THUMB<!----><!---->
Direct gain required mass:<!----><!---->
0.6 x SSF x sf solar glass = lbs. water<!----><!---->
3.0 x SSF x sf solar glass = lbs. masonry
South-facing glazing = 7% - 12% of floor area<!----><!---->
<!----><!---->
Mass = 6 sf (4" thick) direct-gain mass per sf glazing above 7% <!----><!---->
Masonry is 2 to 3 times more effective if in direct sunlight <!----><!---->
(excess mass can be liability when temp drops below normal)<!----><!---->
<!----> <!---->
Thermal mass and heavy insulation dampens the daily temperature swings.<!----><!---->
Excess solar glazing will heighten daily temperature rise and deepen night-time temperature plunge.<!----><!---->
ABSORPTIVITY
flat black paint .95<!----><!---->
dark grey paint .91<!----><!---->
dark brown paint .88<!----><!---->
dark green lacquer .88<!----><!---->
medium brown paint .84 <!----><!---->
medium rust paint .78<!----><!---->
red bricks .70<!----><!---->
uncolored concrete .65<!----><!---->
medium orange paint .58<!----><!---->
medium yellow paint .57<!----><!---->
medium blue paint .51<!----><!---->
white semi-gloss paint .30<!----><!---->
[absorptivity below .60 substantially reduces performance]<!----><!---->
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
You don't have any sun in north Texas, do you? ;-)
Your Personal Quote:<!----><!----><!---->
"Keep the rain out.Keep the outside air out.Keep the inside air in and let the moisture out in both directions" per Lstiburek
Says nothing about letting the sun in - or keeping it out, for that matter.
Thanks for the solar nuggets...what took so long :-)
For my climate:(hot/mixed humid)
I would take that Lstiburek quote and then add:
Ventilation management
solar strategy
then appropriate insulation
My simple free calculators:http://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htmhttp://www.builditsolar.com/References/Calculators/InsulUpgrd/InsulUpgrade.htmGary
Thanks for the links, Gary. I plugged in my numbers and came up with lots of useful data.
The first thing that jumps out at me is how significant it is to go super-insulated, particulary with a moderately large home, say 2500sqft.
Next glaring number, not surprisingly, is heat loss through windows. I'm definitely going to experiment with the insulated shutter concept for large areas of fixed glass.
The good news is that, with a super-insulated home, electric heat is workable. So using a wood stove as the primary heat source with electric baseboard as secondary is going to work admirably and relatively inexpensively.
You guys are the best. I am very happy to see all the replies. The ideas are great. I hope that when the time comes what we are now proposing will become the "norm" by the time I am ready to build (2-5 years).
I realize that may be over optimistic as the building industry changes at a glacial pace. Due to the fact that so many people will be hit vary hard in the pocketbook to heat/cool in the coming years may make these changes accelerate.
I am sure that we will continue to see more and more new products and procedures for building energy efficient homes quickly come out. The difficulty will be separating the hype from reality and there will be a lot of homeowners that will get caught in the marketing bs.
I am thankful for a great group of people that have the day to day experience in the field and are willing to share their combined knowledge and wisdom is priceless.
Thanks again to all for your time and trouble to respond to my questions about the "current" best practices to design/build a superinsulated home.
Humbly
Jim Flood
Thanks again to all for your time and trouble to respond to my questions about the "current" best practices to design/build a superinsulated home.
Oh, well that's a different question.
For the current best practice (to the dismay of all my detractors), go to:
http://www.builditsolar.com/Projects/SolarHomes/LarsenTruss/LarsenTruss.htm
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
"The good news is that, with a super-insulated home, electric heat is workable. So using a wood stove as the primary heat source with electric baseboard as secondary is going to work admirably and relatively inexpensively."If you figure you'll be there most of the time and will keep the wood stove going (and the wood pile supplied), then you still have to figure out how to control the heat output of the woodstove. Even a small woodstove can put out twice as much heat as your house may lose when it's zero outside.I'm not criticizing. I'm figuring on having a small stove in the lower level of mine, for backup and, well, I like the process of getting the wood supply ready outdoors in the cooler months, and I like a good wood stove fire.If you'll have a drilled well anyway for domestic water use, then having a very low heat load makes installation of a ground source heat pump worth looking at. Think of it as getting the electric heat at one quarter of the price per kwh, and summer A/C as a freebie.
Dick,
I've yet to do any serious study of heat pumps but then I've only recently seen the light about super-insulated spaces. I'll make a point of putting in a few hours of research on that subject. If you know of any good references I'd like to know about them.
BTW, what advice do you have about domestic hot water as it relates to electicity and wood?
Truth be told, I'm really looking at electric heat for primary and wood as a back up. Not for my DW and I but for the family who buys this home. This will be the first of several homes for us during retirement, each built to take advantage of the capital gains exclusion and provide us with funds for travel and other activities.
The DOE has some spreadsheet calculators that you can play around with to see what kind of ROI you will see on HVAC upgrades.
http://energystar.gov/index.cfm?c=bulk_purchasing.bus_purchasing#reshvac
Jon Blakemore RappahannockINC.com Fredericksburg, VA
Thanks for the link Jon. That's a good place to get some straight facts, without the sales pitch.
I like the whole heat pump concept a lot, just not sure how long it would take for it to pay off it's investment, compared to electric baseboard heat.
I'll have to get a little deeper into the planning stage to find those numbers but it'll be interesting to learn more about it all.
As to GSHP, you can Google up all sorts of info and case studies. There is one forum I look at from time to time:http://www.greenbuildingtalk.com/Forums/tabid/53/view/topics/forumid/13/Default.aspxAnd one apparently well-versed system designer (good system design is essential) has a web site at:http://www.northeastgeo.com/I have no advice on domestic hot water, other than if you have an electric hot water heater, make it a very well insulated one. The NH Electric Coop has been pushing the Marathon heater.Domestic hot water by wood fire? It's done, but I imagine it might hurt ultimate resale value. I would think most folks would like the enhanced comfort and low utility bills of a superinsulated house, but might balk at hot water needing frequent attention to keep the fire going.You can get GSHP with an option for hot water heating by desuperheating the refrigerant from the compressor when in A/C mode (essentially free heat that would have been dumped to well water anyway). Maybe by now a vendor has an option to provide hot water heating even when in heating mode in winter. That's something I want, too. I'll have to check the Climatemaster and Waterfurnace web sites again to see what's new with them. Imagine, electric hot water heating at 1/3 the electric cost (assuming the COP is that much lower to pump heat up that much higher to dump to 120 degree hot water).
I've done some limited research on GSHP, but for my needs they don't seem as effective (heating only). I looked at this one from waterfurnace http://www.waterfurnace.com/marketing/brochures/pdf/WF1412.pdf
from what I can tell it will do heating, cooling, and DHW.
As far as Electric WH go the marathon is top notch for a tank imo, if your needs are just for DHW you could consider a tankless option maybe?
Thanks for all the good info. I haven't had time to get into it yet but I wanted to pass along one thing I learned from the DOE linked site provided by Jon B.
It seems to be what you were thinking about when you wrote: "Maybe by now a vendor has an option to provide hot water heating even when in heating mode in winter. That's something I want, too."
"Integrated demand water heating differs from desuperheater in that the integrated demand water heating model provides all or nearly all of the domestic hot water needs and provides hot water even when space conditioning is not required. This includes systems that employ the use of a separate water heating compressor unit or that use the same compressor for space conditioning and water heating. Also sometimes referred to as full-demand or demand water heating."
On the subject of DHW by wood fire; I don't have any expectations of finding a stand-alone system which would be acceptable to modern home buyers.
What interests me is the idea of preheating large amounts of stored water to room temperature (example; a one thousand gallon plastic tank at 68-70 degrees) for DHW by both solar and other means. That would bring the well water up about fifteen degrees, saving the water heating device that much work and fuel
In addition, such a large amount of temperate water would be quite a nice thermal mass and have positive effect on maintaining the temperature of a super-insulated home.
Edited 3/26/2008 9:12 pm by Hudson Valley Carpenter
BTW, what advice do you have about domestic hot water as it relates to electicity and wood?
If you're planning a central HRV system, you can recover the outgoing heat into water instead of air, using an exhaust air heat pump with a COP of 2:
http://www.oikos.com/esb/41/eahpstudy.html
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
"If you're planning a central HRV system, you can recover the outgoing heat into water instead of air, using an exhaust air heat pump with a COP of 2:"
http://www.oikos.com/esb/41/eahpstudy.html
Hey, pretty ingenious. A bit pricey, unless there's a govt. rebate, but it certainly fits the super-insulated, all electic concept nicely.
Hi,I am really impressed with this home in Edmonton:http://www.riverdalenetzero.ca/Net zero on both heating and electrical use, R100 ceiling, R56 walls, ...
Triple and quad glazed windows.
Passive solar heating + active solar water and space heating.
Plus A depressingly expensive PV system.The power point presentation is pretty detailed once you get past the introductory slides -- its 10 MB, but includes construction detail and quite a bit on how they arrived at the details of the design, and why they did not use other details, including some comments on why a GSHP, evac tubes, and SIPs were not used:
http://www.riverdalenetzero.ca/PRESENTATIONS/Riverdale_NetZero_energy_home_--_2008_01_09.pdfGary
"If you're planning a central HRV system, you can recover the outgoing heat into water instead of air, using an exhaust air heat pump with a COP of 2:"
http://www.oikos.com/esb/41/eahpstudy.html
Couple of questions: Have you installed one of these and had feedback from the HOs? Can this system be thermostatically controlled to run when the temperature rises above the setting? Just like to know if it would use extra heat generated by a wood stove to heat DHW. Similarly, would it cool the house in summer and heat water too?
I have no first hand (or even second hand) experience with exhaust air heat pumps, but I suspect they can do what you're asking.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
I have no first hand (or even second hand) experience with exhaust air heat pumps, but I suspect they can do what you're asking.
Thanks, I'll call or write the company and see if I can get those questions answered.
Another very cool idea, thanks for posting that.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
The good news is that, with a super-insulated home, electric heat is workable.
Yes, in terms of $ and ¢. But, did you notice the difference in CO2 contribution? Electric puts out 4 times as much per million BTU as any of the other fuels.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
HVC: "The good news is that, with a super-insulated home, electric heat is workable."
"Yes, in terms of $ and ¢. But, did you notice the difference in CO2 contribution? Electric puts out 4 times as much per million BTU as any of the other fuels."
Where, pray tell, might I have noticed it? ;-)
My inclination is to say that my neigbor's oil furnace is the worst, second might be my wood stove, third a more efficient LP boiler and fourth; the combined energy sources used to produce electricity.
I'm aware that a lot of electricity is produced using fuel oil and coal but there are scrubbing systems installed in modern oil/coal burning plants which are supposed to severely limit CO2 emmissions.
Edited 3/26/2008 9:35 pm by Hudson Valley Carpenter
Where, pray tell, might I have noticed it? ;-)
http://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm
last column.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/26/2008 8:30 pm ET by Riversong
Ah...so, hiding in the dark green column.
I have to say, I'm a bit skeptical about them offering something as objective data, which is so difficult to measure and has so many variables in actual usage. I'll have to get on their case and ask where they got their data, how it was arrived at.
Hi HVC,...
"I'm aware that a lot of electricity is produced using fuel oil and coal but there are scrubbing systems installed in modern oil/coal burning plants which are supposed to severely limit CO2 emissions."I don't believe there are any electric plants in the US that recover CO2 and sequester it. There is a lot of talk about it, and the DOE is looking for some utilities that will do some pilot programs, but nothing yet. Part of the problem is that the amount of CO2 is huge -- if you think of the 100 car train load of coal feeding a big plant every couple days, the weight of CO2 generated is several times the weight of the coal that comes in.
Good article on this:
http://www.nrdc.org/onearth/05fal/coal1.aspGary
"I don't believe there are any electric plants in the US that recover CO2 and sequester it."
Twenty years ago I worked as a union carpenter for one of several contractors who were involved in re-fitting a NY State Consolidated Edison generating plant on the west bank of the Hudson River, a few miles north of Newburgh. One major part of the work was installing the scrubbing devices in the furnaces and the giant chimneys.
The overhaul was all about converting the plant from oil back to coal, which had been it's orginal fuel. Before the conversion the chimneys put out brown haze which could be easily seen for miles away. Afterwards there was no visible smoke, only some steam.
I realize that's not scientific evidence but I can attest that the work was done. It took hundreds of men almost a full year to complete it.
Afterwards there was no visible smoke, only some steam.
Scrubbers remove sulphur and some particulate matter. Particulates and SO2 have been regulated forms of pollution.
Remember that the US government and the EPA (largely because of Bush's oppostion) has not considered CO2 to be a pollutant, hence it is not regulated.
Scrubbers don't remove CO2.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 3/27/2008 11:04 am ET by Riversong
gary, thanksMike Smith Rhode Island : Design / Build / Repair / Restore
Assuming that someone only has X amount of dollars for construction, what would you estimate the per centage of the budget to be for super insulation methods over conventional construction? Kind of a convoluted question. How much would you be taking from other parts of the job to pay for super insulation? Don't account for energy savings over time.
Thanks, John
a lot of subjective stuff goes into developing those cost projectionsmaterial costs are sorta straight forward... but trade prices are subject to interpretation...
most of the insulation subs i've seen ( with fiberglass ) don't do a very good job... so do we assume standard installed prices .. or do we add for the extra labor of doing it right ?and ... what is your definition of "standard" constrution? shall we say : 2x4 @ 16" oc
and R-13 fiberglass ? does that include a vapor barrrier ?or is it R-11 and no vapor barrier ?where you live determines what the code minimum is .. is that to be our criteria for "standard insulation ?Mike Smith Rhode Island : Design / Build / Repair / Restore
John
102383.223 in reply to 102383.222
I added 2x6 wall with FG batts as the lowest denominator.
30' x 60' Structure No doors or windows 1800 SF floor space, 180LF of wall 8' walls and 1680 SF of Ext. Wall
Materials only no tax no labor cellulose at 1"= 3.5 R All walls 16" on center
2x6 with FG batts 1/2" OSB R19.5 $2,686 $1.59/SF
Mooney wall 2x4 with 2x2 horz. furring and densepak R-18 $3,237 $1.99/SF
2x6 with FG batts 1/2" OSB and 1"XPS R-24.5 $3,775 $2.33/SF
Maine Builder Double 2x4 w/OSB Truss DensePak R-42.5 $4,483 $2.77/SF
12" I joist 1/2" OSB and Dense pak R-42.5 $5,961 $3.68/SF
ICF Walls 4" XPS w/ 8" concrete Liteforms R-28 $8,702 $5.37/SF
The difference between the lowest and the 12" I-joists is just $3,275.
The difference between the lowest and the ICF is just $6,016.
On a $250,000 house I don't think that is too much to be worried about. Now the labor to do any of these wall systems may be a different matter. But like Mike said most FG batt installations are not too good.
There is going to be additional costs with a deeper wall like window and door jamb extentions. But I don't feel like doing an complete cost study at this time. That it why I said repeatedly that the above was a very simple cost summary.
Rich
This has been a great thread. I found the article in Fine Homebuilding interesting. It would have been nice if the author had gone into a little more detail in the drawings on how you put four inches of foam board insulation on the outside of the house and attach the furring strips. I'm guessing that they used screws, but what type and what was the spacing? My house was built in 1959 and has thin fiberglass batts in 2 x 4 walls, so I'm doing some research on what can be done to help. I did find this website. http://denverenergyawareness.org/Superinsulated-Retrofit-Overview.htmHere is a direct link to the process.http://denverenergyawareness.org/Superinsulation-Process.htmWhat do you think of the method? There is some bridging where the furring strips cross.Thanks,
Kenny
Edited 3/31/2008 2:33 pm by 1hotwire
Kenny
That was an interesting link. I will make 2 points.
I do not believe poly iso is supposed to be used underground. Probably should have used XPS.
I would be concerned about the window detailing with the window set in 4".
Would have been better if they would havemoved the windows out as long as they were going to all that work.
Rich
Thought I'd add another interesting related product I've been reading about, electric thermal storage units.
They are meant to take advantage of off-peak rates and seem like a good fit with super insulated homes. http://www.steffes.com is one well respect manufacturer of these systems.
that big victorian we built in 1985 uses electric ceramic thermal storage heaters
back in the good olde elctric off-peak rate daysevery house we built for a while back then had two meters... one for continuous.... one for off-peak.......
that all went away with deregulation of the electric industry... kind of funny... right now electric is cheaper than fuel oil heatMike Smith Rhode Island : Design / Build / Repair / Restore
My utility company is offering a BIG off-peak deduction in their delivery rate, down from a high of about eight cents/KWH to one cent/KWH. There's an additional monthly fee for the TOS (time of service) program, about eight bucks a month.
On the actual cost of electricity, there's no off peak break. Right now it's all about eleven cents/KWH. According to the customer service rep I spoke with at the utility company today, the cost of producing electricity is very closely tied to the cost of natural gas.
Still, I like the ETS heater idea for super insulated homes better than any of the alternatives. Not a big investment, very self sufficient.
Add a similarly efficient electric DHW heater and a small woodstove, then wait and see where the government and science will take us next.
BTW, is there a photo thread on the Big Vic?
Edited 4/2/2008 9:33 pm by Hudson Valley Carpenter
wanted to get this one back on top tooMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Mike
What did you want to talk about?
It was -14 degrees yesterday morning. It kind of gets one dreaming about building a super efficient new house.
This one is paid for so I guess I am going to stay here for a while.
Rich
somebody emailed me to talk about superinsulated houses... so i went looking for the respective threads
got anymore ?Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Mike
I'll bump a couple that I saved in my links.
Rich
wanted to get this one back on top too
Good idea Mike,
Thanks for the bump. I don't believe I've seen this thread before so it should be interesting to read.