I’m in a cold climate (MN) and working on a remodel that will open up some exterior walls. The existing 2X4 framing is staying. I’m thinking about using expandable foam to maximize the R-Value, but haven’t used it before. Besides cost, what are the pro’s and con’s to using foam? I’ve also heard conflicting stories about whether or not I need to use a vapor barrier. What’s your recommendation regarding a vapor barrier?
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Replies
You want an air barrier, not a vapor barrier.
In your climate, a vapor barrier is going to trap moisture inside the wall where it will condense or freeze.
tuffy,
I'm sorry you have it wrong, you want a vapor barrier on the inside and an air barrier on the outside. That or we're all wrong here in Minnesota and should listen to you..
By the way My credentials are that for a living I visit new homes Here in Minnesota all day long 5 days a week. I've done so for the past 15 years.. oops, almost 16 years.
Door to door forklift sales?
What's up with that?SamT
Anyone who doesn't take truth seriously in small matters cannot be trusted in large ones either. [Einstein] Tks, BossHogg.
SamT
That's how it's done!
framing contractors (our biggest customer base) don't have offices to go to. Most operate out of the cab of a pickup, they also tend to not have a lot of advertizing.(well any actually) the way you find them is go to where new homes are being built and start talking to people. In addition, You need to find building contractors to know where they intend to build in the future and who they intend on using..
The actual sale of equipment is realtively easy, finding the potential buyer is the hard part..
"Door to door forklift sales?What's up with that?"No finer way to study foam insulation! Don'tcha know?
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
There's no reason to get snippy.I've left some huge caveats in my posts. If there's something I don't understand about the climate conditions in Minnesota that would influence the proper application of barriers and retarders, then by all means, please enlighten me.I mean no disrespect, nor is it my intention to belittle your experience and expertise, but, "I've done so for the past 15 years..." does not do much to persuade me of the validity of your assertions. Don't just tell me you're right and I'm wrong--explain it.DanH stated that the outdoor dewpoint in Minnesota in summer would be such that condensation in the walls isn't a concern. That's an absolutely germane point. In Nebraska, we see a lot of newer homes plagued with problems, and in some cases practically destroyed, because some builders have harbored the belief that polyethylene is just as effective as proper housewrap. A couple of years ago a new house near me had the sheathing and siding burst right off the studs because the builder stapled a vapor barrier up instead of an air barrier. When someone opened one of the walls up, it looked like the inside of an undefrosted freezer.We get lots of mold problems in some newer buildings--frequently from improper use of vapor barriers, but often enough just from something like the use of vinyl wallpaper. Someone puts up a wall covering that's moisure-impermeable, maybe on the north side of the house, and they end up with moldy drywall.I would still think that unless you're somewhere very cold and very dry, it would be preferable to eschew an interior vapor barrier in favor of a vapor retarder.
As I stated, in Minnesota the summer dewpoint rarely exceeds the indoor temp, so vapor driven from the outside is not a serious concern. OTOH, we often have several months where the temperature outside is well below the indoor dewpoint. Absent some control of vapor passing through from the inside the insulation can easily become loaded with ice.For this reason a vapor barrier on the inside is a must, and is required by code. In general this means poly, since the backing on fiberglass is rarely reliable as a VB.Outside, under the siding, a housewrap is also a must (and generally code-required), as an infiltration barrier. Proper housewrap (Tyvek, Typar, et al) prevents air infiltration and sheds liquid moisture, but does not seriously impede the flow of water vapor. Preventing air infiltration not only helps keep the house warm on days like today (ten below and 15MPH wind at noon) but also prevents cold spots in the insulation (especially FG) which can result in ice formation in the walls.I've never heard of folks having trouble with vinyl wallpaper etc. In winter months mold may appear in walls due to cold spots (temperature below the dew point at the surface or just behind the drywall) or due to ice damming. It's fairly common for such spots to show up behind a large piece of furniture, eg, because this causes the wall to be colder. At other times of the year you'd only have a problem due to rain leakage.I'm guessing the situations you've seen have been erroneously ascribed to vinyl wallpaper when in fact they were due to vapor passing through from the inside.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Thanks for the elaboration. I was genuinely curious about the differences for MN vs. NE, considering MN being further north, bordering Lake Superior, wondering what the effective net difference would be.The vinyl wallpaper would be more of a summertime concern. Hot muggy day...air conditioned house...maybe a shaded north wall...perhaps leading to a buildup of condensate in the drywall with nowhere to go. It seems like every time I've pulled up vinyl wallpaper there was moldy drywall or paneling behind it. Yuk.Since your codes require a vapor barrier (Class I?), do they address ventilation as it relates to this? I see someone tacking up polyethylene inside the studs, and I feel those cartoony exclamation points pop up over my head thinking about IAQ.
No ventillation in the walls. Unheated attics require ventillation.I am having trouble believing that Nebraska is that humid in the summer. The conventional wisdom is that summertime condensation is only a problem in southern states. Basically, it can only be a problem when conditions are sufficient to cause condensation on the outside of windows in the summer.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Here in the Northwest we have to deal with similar temperatures as in Minnesota.
We build costefficiently and troublefree with this wallstructure:
Exterior wall: woodframeconstruction 2x ---, MINERAL batt insulation, small cavities filled with expanding foam, 6mil poly on the inside, 1/2 sheathing, 2 layers 60min tarpaper with sealed seams, 3/4" spacer acting as airspace behind exterior finish, screened on the bottom to prevent insect infiltration, second layer of sheathing, exterior finish. If we use stucco, we separate the the stucco from the sheathing with another layer of tarpaper.
Never had any problems
Hi. Care to elaborate a bit on your dissertation about Nebraska, and tell me if IYO I have worries ahead? I'm outside of Omaha, and building a ~2900SF 2-story. Here's my house, from the outside in:
1) Alcoa Structure siding (vinyl w/attached XPS foam backing)
2) Tyvek
3) Blown-in fiberglass (BIBS)
4) Poly vapor barrier.
We're about two days from start of drywall - anything I oughta worry about? Should I go in tomorrow and pull down the poly?
Jason
Better check with building inspector before you pull off the vapor barrier. Would be a shame to have to pull all the drywall down to put it back because of a code violation.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Just make sure the homeowner doesn't put up any vinyl wallpaper. *grins like a really big dork*
Just make sure the homeowner doesn't put up any vinyl wallpaper. *grins like a really big dork*
Actually, I am the HO, so I can categorically state that the likelihood of any wallpaper, vinyl or not, being put up is roughly the same as me starting for the Yankees in April. : )
As for the inspection concern cited, how would the inspector know if there weren't a VB under the drywall? We don't have a post-drywall inspection, AIUI, until it's time for the CO (though I could be wrong, I guess).
Jason
tuffy,
I sure hope I wasn't snippy. I always try not to be. I understand your position. frankly I still make that mistake myself. I was blathering on in another post about how cost efficent SIP construction was compaired to stick building.. How the potential energy savings were a bonus..
It turns out where he's located energy use wasn't a major factor the way it is up here in Minnesota, because of that there are few SIP manufacturers around and thus the cost of the SIP's includes a great deal of shipping and other charges that makes SIP's less affordable..
But I found that just the raw cost of material made SIP's a better buy than stick building.. Totally ignoring the energy savings potential of SIP's
IN addition as a DIY guy my labor cost is whatever, I don't have the experiance to bang out a quick wall and set it in place quickly the way certain pros do. So the ease I could just put a panel in place and tip it up really made the differance in time between the two systems dramatic.
Only 1% of all homes are built with SIP's 99% of all contractors have no experiance and the rest very little..
There are a multitude of unfounded myths out there that I found to be pure hogwash, but I can understand how they got started and why contractors charge a premium to build with a product that is both faster and cheaper.. once building with SIP's becomes common costs should plummet dramatically.
Your experiance with contractors using the wrong material is really what this board is all about.. far better to learn what's right here than later in the field ..
I've visited a grocery store roughly once a week for the last 35 years. Does that mean I know anything about the grocery sales business? Actually I'm an expert. Throw out the fruit when it starts getting brown! Oh-Oh - yesterday my wife drug me into a shoe store to look at women's shoes with her. They all looked "fine" to me. I guess I know about that too.
Frenchy is a eccentric DIY who sells construction equipment. Anyone who wants to make building decisions based on one man's experience on one or 2 houses is more than welcome to do so. Other than that, a guy pulling up in front of a house under construction, trying to get the attention of the head framing sub, while not getting his shoes dirty doesn't learn how to build a house via telepathic powers, even if he would like to.
Frenchy: Do you want any advice on fork lifts? I drove one for 3 months when I was 20 years old. I thought not.
Anyone who's lived in Minnesota for a dozen or so years and has concerned themselves with standard residential construction (even as a homeowner) is aware of the issues regarding vapor barriers.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Not saying Frenchy doesn't occasionally have valid points. I've seen some excellent posts from him on salesmanship and construction site heavy equipment.
The above was just a knee jerk reaction when I read his statement about foam making the house stiffer - yes, well, I guess sheetrock, and even paint does that too...
I just lost respect for him based on some of his past posts like:
- The ones where he kept insisting that cellulose insulation was causing moisture problems in his house.
- The one where he said a forklift was the best machine for demoing a house.
- The one about screwing down dimensional lumber rafters with lag screws.
- The one recently recommending lacquer for finishing hardwood floors was amusing - not that it won't work, if you don't mind being chained to a floor waxer the way my dear mom was.
We are all here to share our ideas, information, and opinions, I just have a problem with people who present themselves as experts on topics that they have only had casual (non professional) involvement with.
MarkT
you have to get your facts correct if you intend to critise me.
I said a telehandler is a wonderful device for demolishing a house. I did my house in minutes MINUTES! with one.. if you'll pay the transportation charges I gladly demolish one to prove it.. bring the cameras!
Celluliose insulation was in my house, my heating bills were $500.00 a month in Jan.& Dec. I can show you those. stop by..
Currant house is far, far, bigger with more windows and not fully sealed cost me a little over $125 per month for Jan. & Dec. using the exact same furnace and kept at a warmer temp because of a new baby..
I did not say deminsional lumber, I don't use demensional lumber and yes I do believe in lag screws. So does Fine Home Building because when they tested it it was superior.. (actaully they just did an article about it. It was tested by the University of Wisconsin's wood labratory, met all scientific criteria)
Finally I did not suggest lacquer,,.
I said shellac..
Maybe you aren't aware they are vastly differant? Would you care to come here and walk on my shellaced floors? Please reread what I posted, you might honestly learn something.
Well stated.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
MarkT
Thank you for sharing that with me, it just shows you exactly how little you know about selling..
I have a 4WD truck because I drive thru the mud to reach job sites often.. the same goes for my boots, they are often plenty muddy by the end of the day.. and my pants and if I slip, all of the clothes.
If I don't know what I'm talking about darn few contractors would waste more than a few minutes with me, let alone spend nearly $100,000
I need to know how and why they are doing their job.. otherwise how can I offer them a better way to achieve their goal.. Nobody spends that much money to brag they own one, they buy because it makes sense. Pure raw business sense..
As long as I've been doing it I'm still amazed at the errors the average nonforklift owner makes in his assumptions..
For a quick example.. they save the most money on the floors not putting up rafters. In fact I often suggest they continue using a crane service to put up rafters for maximum return on their labor dollar..
ECD
On a remodel foam is your best insulational value.. it adds a great deal of stiffness and makes the house more solid and quiet. Plus it will lower your energy bill over other forms of insulation..
Yes you still will need a vapor barrier.. not because moisture will get thru the foam (it won't) but because the moisture will go thru wood if it has too. Wood is hygroscopic that means it absorbs moisture from the air.
You can prove this for yourself if you carefully measure a wide board that in a nice dry house in January and then again this summer after a really humid period.. That increase in width is the result of moisture causing the wood to swell.
I would think it might be worth considering the ultimate value of a vapor barrier in Minnesota. Water vapor tends to move from the warm side of an envelope assembly to the cold side. In cold weather, humid indoor air can condense inside a cold wall. In warm weather, humid outdoor air can condense inside a cold wall.You want to place a vapor barrier on the warm side of the wall only. You also want to avoid a vapor barrier when a vapor retarder will suffice. In a hot and humid climate, you want to place an air barrier on the outside of the insulation. In a cold climate, you want to place a vapor retarder on the inside of the insulation.I'm not a climatologist, and I don't feel like spending a half hour digging up data on Minnesota, but I would think that generally when one is approximately in the midwest, one may experience both very cold and very hot and humid conditions seasonally.What's most ideal for the winter may cause moisture problems in the summer. No one wants ice in their walls, but I can't imagine most would be terribly keen on mold in them either.I don't know specifically what kind of foam the homeowner is considering using, but I question the assertion that moisture won't pass through foam. Perhaps it depends on the foam. On Icynene's website, it states in the product specs that Icynene is water vapor permeable. Icynene itself is an air barrier, but not a moisture barrier.
Edited 2/3/2007 8:48 pm ET by tuffy
In Minnesota, though it does get hot and humid at times during the summer, the dewpoint rarely exceeds typical indoor temperatures. Therefore, summertime condensation in the walls is not a concern.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Icy would neeed a VB, poly will not
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
still expanding your goofy moisture movement myths, I see.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Yeah, foam or cellulose, with a vapor barrier on the inside. But most important in our climate is careful attention to sealing against air infiltration.
I've been thinking that a cheaper alternative is to use 3.5" polyisocyanate foam board and just use the $$$ spray along the edges and around plumbing and eletrical. Same or higher R-value, lower cost, same air infitration advantage.
Anyone have an idea why this is a horrible idea? *g*
Reyesuela,
The main disdvantage of riged board is the difficulty fitting it to existing walls.. sprayed in foam goes in so quickly that a whole huse can be finished in a day rigid foam cut and fit would take weeks to do.. and the end results wouldn't be as successful..
I'm not understanding why cutting it would be *so* hard. It wouldn't be cut to *fit* ---there'd be an 1" gap all around to be foamed. You can order the foam board ar whatever thickness you want. With the price of foam at around $12/cuft and with the isocyanate at about $5/cuft, unless it takes someone an hour to do two bays, I can't see why it wouldn't be cheaper...especially if you DIY in your spare time. ;-)
Reyesula,
OK I'm wrong.. I'm just horribly slow and inept. Because when I did it It took me 40 hours to cut and fit foam into the over hang on the front of my house.. The overhang amounted to 15 inches at the lower level and 8 inches at the upper level. 30 feet across. That is 15x15 & 8x8 40 hours. It takes but a minute to do I thought.
It was straight forward work, nothing went wrong, I had the foam right there and cans and cans of the spray foam top seal the edges. Or should I say a couple of cases of the stuff. PS I left as small a gap as possible because you'll find out for yourself how darn expensive that spray foam is if you start to leave a one inch gap..
Now when I did my tower that took me more than a month of my spare time. I fit foam between the timbers (every 6 inches for 18 feet on a 12 foot tower)and then used cases and cases of spray foam to seal it up. I didn't have to do much of the tower because it was inside the heat envelope just the parts that the outside wall was exposed to weather.. about a third of it.. Now I built some tempoary scaffolding so I wouldn't be climbing up and down a ladder but the time it took to build it I more than saved in being right there and having all the required materials on hand..
Finally I will state for the record it would have been cheaper just to have someone else spray it in and trim it off..They did my brother-in-laws whole house in a day.
I suspect that between buying the foam and the spray I spent more than it would have cost to have it done.. that 200 hours I spent doing it I'll just chaulk up to a learning experiance.
PS. If you've followed the progres of my home you will realize just what a cheapskate I am and how despriately I look for deals and cheaper ways to do things..
I'm curious about how this was framed if it took so long! Once you knew the measurements of one bay, couldn't you just cut them all at once? First, measure. Then cut everything. Then place and foam.
Reyesuela,
Apparently you think I'm some kind of dolt who doesn't think things thru, That's OK. I will state that if you try it yourself you will learn the lessons I learned, but then you won't have the advantage of learning from others mistakes..
I wish someone would have taken the time to help me out on this. I mean I was shocked at how long the task took that should have been so quick.. I guess that's part of DIY.
Many things have taken much more time than planned. a few things went better and faster than expected but in general whenever I budgeted time for a task I learned the hard way to estimate worst possible case and then double it.
The time and effort required would have been dramatically reduced if I'd had someone with me doing part of the work. Hand me up the foam for example rather than having to climb up and down that ladder 60 jillion times..
Luckily I didn't have to fit stuff around existing wires, ductwork, or pipes. Electricians never put wires in conveniant spots. Duct work is nearly impossible to fit rigid foam around.
I thought I would save money over having it sprayed in. That wan't the case.. I'll bet I used nearly a hundred cans of spray foam and at over $5.00 a can that's a fair amount of Jing. Plus buying the foam, and hauling it home. I easily spent more money than having it sprayed in would have cost me..
Since I've done it I will simply state that in the future it will be sprayed in rather than fitted by hand. To eliminate excess set up charges I will have the rest of the house finished off at once.
I don't think you're an idiot. I'm genuinely puzzled as to how it can take that long and was looking for elaboration.>Hand me up the foam for example rather than having to climb up and down that ladder 60 jillion times..See, this helps. :-) I have a DH for unskilled labor.>I'll bet I used nearly a hundred cans of spray foam and at over $5.00 a can that's a fair amount of Jing.Ouch. This also explains a lot. It made no sense to me that DIY PARTIAL foam would cost more than pro FULL foam, but if you bought cans, absolutely. I'd buy 300 or 600 bd-ft of Tiger Foam from the start. I know I'd use quite a bit!
Edited 2/8/2007 2:24 am ET by Reyesuela
Reyesuela,
You should also know that it's a timberframe. the sawmill isn't particularly careful when they saw my timbers and a 1/4 inch variation isn't all that unusual. so the space between timbers could be between 10 1/2 and 9 1/2 inches. (I put them on center rather than space them equal distance apart. Done in part because I like the character it adds to my home and because I have a mania about bouncy floors. For example I went for 80# loads on the second floor and then added a giant safety factor.. actual load rating is probably around 120#'s
I can afford to do so because the price I pay for hardwood timbers wouldn't buy the average contractor sheetrock..
I digress,
I do have to cut each foam panel for the location in order to avoid using as much spray foam as possible..
But still if you've ever seen a spray crew do a whole house in less than a day (a big house with a lot of bump outs, dormers, gabels, and nooks and cranny's to fill, two stories and an attic, you'll accept that there is simply no way you can do it as fast yourself. Plus you will have to make some real sacrafices in either speed or material as you work around plumbing and wiring..
Don't forget the cost of your haircut afterwards!
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Don't forget the cost of your haircut afterwards!Ha...After work, job super and laborer were goofing around with some great stuff...laborer shot some in the super's shirt pocket...super calmly took the can, grabbed the laborer's waistband and unloaded the can in his pants...talk about a haircut SLOL "But to be honest some folks here have been pushing the envelope quite a bit with their unnecessary use if swear words. They just put a character in to replace a letter. But everyone knows what they're saying." Sancho
LOL, Talk about messing around!and you know how that stuff turns things black.STD in a can....
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I'm still choking with laughter and tears ove rthat one!
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I mean that's not a location where you want to automaticly grab the acetone to cleanup while you still can. How long does a guy think about whether to clean with that or just let it cure....What a choice!
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
and, talk about getting a warm, fuzzy feeling<G>Then, when he got home his wife actually asked him if he was "glad" to see her LOL "But to be honest some folks here have been pushing the envelope quite a bit with their unnecessary use if swear words. They just put a character in to replace a letter. But everyone knows what they're saying." Sancho
Ha! That's why Tiger Foam ALSO sells suits with hoods....
Right - the Tyvek body condoms!What got me started on this was i think i remember a poost from Fenchy 3-4 years ago asking how does one get the foam out of one's hair.We all had fun telling him it was too late to even ask.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I had a hard enoguh time getting glue-down floor adhesive out of my hair. (Hair hits the floor when I kneel and lean over--I was an idiot and forgot to put it up BEFORE I got my hands all mucky.) I'm just glad THAT wasn't permanent.
Piffan,
Thank you for reminding me. But it wasn't foam it was waterproofing, the stuff used to waterproof ICF's before backfilling.. Now that's an old memory. 5 1/2 years ago!
Your advice of using WD40 worked perfectly. a spray of WD40 into my hair and the comb and brush took out it without anymore tugging or pulling my hair. then a quick shampoo and my hair was fine.. thank you again!
Yeah, and it keeps your hair from squeeking as well.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
OK, your memory is bnetter than mine, but then your brain was closer to the problem, LOLThere was somebody here aasking about getting foam out of their hair though. I guess I transposed the memory onto you!
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
>>> a spray of WD40 into my hair ..
I've been thinking about trying that. Did you notice an increase in the interest you were getting from the ladies around you?
shareblade,
The ladies around me are my wife and two daughters,and No they weren't particularly interested in me but then I took a shower right afterwards and the shampoo washed it all away.. are you saying that there is some magical attraction women have for WD40 in mens hair? Think of the commercial! <G>
It works on fishing lures
Maybe he was doing some wishful thinking
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
>>> a spray of WD40 into my hair ..>I've been thinking about trying that. Did you notice an increase in the interest you were getting from the ladies around you?I wasn't around, but I might have had WD-40 in my hair, too, getting the floor adhesive out of it...
Thanks for giving me more info!>But still if you've ever seen a spray crew do a whole house in less than a day (a big house with a lot of bump outs, dormers, gabels, and nooks and cranny's to fill, two stories and an attic, you'll accept that there is simply no way you can do it as fast yourself. Plus you will have to make some real sacrafices in either speed or material as you work around plumbing and wiring..I'm going to pay for everything cash because I don't do loans for additions and improvements, so it's ok if it takes a loooong time. I'm expecting my first addition to take a year, and its "new" footprint is only 14x26'.
Since you brought up Tiger Foam, thought I would highjack the thread - have you ever used it?
I was half-thinking about using the slow expanding wall fill formula on the first floor of my own house (1926 Colocial, plaster walls, full brick veener on the first floor).
Any issues you (or anyone else) can think of with that kind of application? Should I be that worried about the lack of a vapor barrier?
I was half-thinking about using the slow expanding wall fill formula on the first floor of my own house (1926 Colocial, plaster walls, full brick veener on the first floor).
Any issues you (or anyone else) can think of with that kind of application? Should I be that worried about the lack of a vapor barrier?
Few of the expanding foam outfits spend much time explaining the hazards of foaming (insulating) old wiring. In most places it simply doesn't meet code or the wire has to be derated so much it can't handle the current size of breaker.
This may be a good excuse to have at least the exterior walls rewired.
Beer was created so carpenters wouldn't rule the world.
Don't make me spend any more money, now. If it gets to re-wiring we'll be leaving it alone. I would guess that foam would expand into the electrical boxes that are in the walls - they are 80 years old definitely not made to be tight.
It's a half-brained idea, really, since it's been so dang cold around here and it's a new house, at least to me. I liked the idea of the foam for an interior job so as to minimize the dust. It's much more likely that I will blow in cellulose upstairs when I get around to ripping off the vinyl siding sometime before I die.
I haven't used it yet! Sorry. I just looked at a half a dozen companies selling kits, and it was the cheapest. :-)As Piffin about application. I have a couple of questions myself. :-)
I've done it the way you're thinking of doing it, and had it sprayed professionally. It's really a question of your time vs money. You CAN do, for all practical purposes, just as good a job, depending on how careful you are, as the professionals.Leave a 1/4 inch or so gap, as previously recommended, and invest in a foam gun. FAR cheaper then hardware spray foam and infinitely more control. Lots of info in the archives. HTH
I'd buy a small kit from Tiger Foam, at about $1/board foot. I'm not interested in open-celled stuff. (If you had Icyene sprayed, I could see how it'd be cost-competitive, but I'm comparing it to another closed-cell foam.) I thinking maybe I shoud get slow-rise in this application.If you think that closer is better, size-wise, the prescored foam would probably be a good choice. It be snap-and-fit.
BTW, you know the old adage: you can have something done well, done, fast, or done cheaply, but you have to pick 2 of the 3. I'm ok with s-l-o-w for what I'm doing right now. They ALSO make foam that's scored to fit 16" OC or 24" OC foaming, which would make it more practical for faster appliactions.
Some of this may be redundant, I have not read all the posts.
Depends on how much wall you are opening up and what kind of foam you are using.
Polyeurethane is great for our climate. It requires no vapor barrier because it is a closed cell foam (code does not require it), and I'm pretty sure they are now discouraging a vapor barrier with utethane. The walls and ceilings I had sprayed last Thursday don't have one, the ones I'm having sprayed tomorrow will not have one either. In the cities it costs roughly $1/sq. ft./inch of foam. R 7 per inch. Any foam in a habitable space must be covered with sheetrock (except reinforced Thermax).
I would not recommend or use iceneyne in our climate
There aren't many cons except expense.
Thanks for the info.
Why not iceneyne?
The opening would be one or two rooms exterior walls to move some window around. Eventually we'd like to add a second story and foam new construction 2X4 walls to maximize interior area. The foam allows us to maximize R-value in the 2X4 framing.
One of the earlier posts recommended still using vapor barrier since the framing lumber would still absorb moisture without it.
I'm kind of old school and would like to see good air barriers on the outside of the house and no vapor barriers at all to allow the walls to dry both ways.
This makes me think of another question...can you spray foam basement walls that are underground on the outside?
"One of the earlier posts recommended still using vapor barrier since the framing lumber would still absorb moisture without it. I'm kind of old school and would like to see good air barriers on the outside of the house and no vapor barriers at all to allow the walls to dry both ways."That earlier post was from the crackpot who fails to validate his weird moisture movement theories. You are right on this one.
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"Why not iceneyne?"It is an open cell foam, it can absorb moisture. One of the reasons urethane foam is superiior is that the dew point falls within the foam, in the wall assembly. Being that no air or moisture can be move to the place where the dewpoint occurs (within the foam) there can be no condensation forming within the wall.A common misconseption is that moisture is onlly carried with air moving in or through walls. There is also water vapor pressure. The pressure of the water vapor causes the water vapor to move from areas of higher concentration to areas of lower concentration. With higher humidity inside in the winter the water vapor is trying to move out, and vise versa in the summer.
Any foam in a habitable space must be covered with sheetrock (except reinforced Thermax).
How about in an uninhabited (and uninhabitable) basement? I'm considering blown in polyurethane foam on my rubble foundation walls in Maine to reduce air infiltration and covering the foam would be extremely difficult. We have no building code, but I don't want to do something dangerous.
I don't think you would have a problem...unless you have some appliance down there with a flame.In NC, we can have crawl space/ utility areas foamed, and not cover them. "But to be honest some folks here have been pushing the envelope quite a bit with their unnecessary use if swear words. They just put a character in to replace a letter. But everyone knows what they're saying." Sancho
But don't forget that fire in foam, started by a candle being used to check for air leaks, caused the Browns Ferry incident.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Ya, since then, we've only been using the candles for gas leaks<G> "But to be honest some folks here have been pushing the envelope quite a bit with their unnecessary use if swear words. They just put a character in to replace a letter. But everyone knows what they're saying." Sancho
It degrades with UV exposure, so a basement should be fine. Buy fire-rated foam, though.
It must be covered in the basement. This stuff is nasty when it burns. The only foam I know of that is approved is the Thermax mentioned. BTW the foil facing has nothing to do with the fire rating, (you could peel all the foil off and it would still be OK.) You might be able to spray the urethane on your walls followed by some type of fire retardant. I have no experience with this option, but I would guess it is a possibility.
woodroe,
sheetrock!
That's the fire barrier that is required when using foam.. While some communites require fire code sheetrock (5/8ths thick) most asscept 1/2 inch.. once you understand that most foams need the precence of an open flame to burn and will often self extinguishn it's absence. Myths about foam and fire really disappear..
IN fact one of the demonstrations done BY SIP manufactures (A SIP is a foam panel with OSB on either side) is to set a bonfire in the corner of a SIP enclosed room. The walls reach 1200 degrees more than enough to cause a traditonal 2x4 wall to burst into flames, but because of the insulational properties of a SIP not only does the panel not burn, but the exterior of the panel is only 50 degreees higher than ambiant.
"sheetrock!That's the fire barrier that is required when using foam.."Actually the IRC (the code we're using in MN) does not require 5/8" rock anywhere any more (in single family dwellings) and doesn't require fire rated rock any where. If your inspector has required it since we adopted the IRC he is wrong and boys at the state level will straighten him or her out if you ask. But back to the original question. I think he was talking about spraying some stone foundation walls. There are no studs to screw any rock into, thus he needs some alternative fire protection material.
Code or not, I wouldn't finish a job unless all the foam was covered. It's so flamable that any small heat source can have you burnt down faster than a trailer house.
Take a lighter to a block of foam and see for yourself.
Cheers
Beer was created so carpenters wouldn't rule the world.
Thanks, Don. I'm now convinced it's a bad idea.
Steve
"Code or not, I wouldn't finish a job unless all the foam was covered. It's so flamable that any small heat source can have you burnt down faster than a trailer house."IdahoDon, your statement is definitely not true for the fire-rated polyurethane spray foam product discussed in this thread. (Maybe for other foam that I have no experience with) How do I know? I used your advice-
"Take a lighter to a block of foam and see for yourself."I used a MAPP gas torch. While the foam eventually did burn, had to hold the torch flame on the foam to sustain it. After I got a good pile of foam ignited, only then did it puddle and burn- slowly and with much smell.Just for comparison sake, I then used the MAPP gas torch on a 2x4 and plywood sheathing scrap. It took less time to ignite and stayed lit more easily than the foam.That is the sum total of my fire-rating background. It assured me enough that I have sprayed about 10 of the 600 board-foot kits so far.Yes, in the living areas and garage it is covered by drywall- the "foam grotto" look was not as amusing to my wife as it was to me. Heck, I was even making cool stalactites and everything!EDIT: I do not mean to imply that foam (fire rated or not) need not be covered by sheetrock. Code or not, it makes good sense to cover it with rock. I was trying to make a joke about the "cave look"!
Edited 2/12/2007 3:59 am ET by lcdeyes
At least our exposed foam from both ridgid sheets and ICF's are highly flamable. There is some foam that simply has a hard time burning and would be much safer to keep exposed.
Beer was created so carpenters wouldn't rule the world.
Idaho Don!
Highly flamable?
Not hardly! In absence of open flame feeding it it will burn itself out!
In fact one of the best Videos offered on the subject shows a SIP room with a bonfire in the corner.. Tempurature at the interior of the wall was 1200 degrees, temp on the outside of the wall was only 50 degrees above ambiant.
If you built a bonfire in the corner of a stick framed house you'd find the wall quickly in flames!
(heat from the bonfire would quickly raise the interior temp to ignition point and the studs would start to burn!
Until it's covered, our ICF's are no different from a styrofoam cooler. It burns quite well.
Covered with something it wouldn't since there's no oxy getting to the foam. I have no doubt your SIP example is real, it's just not what I'm talking about.
Exposed foam is a no no around most places I've worked under IRC or UBC. Outside the city limits' in Wyoming where there's no code, it's still considered poor practice to not cover bare foam unless the manufacturer has some data on fire resistance.
Beer was created so carpenters wouldn't rule the world.
IdahoDon
You're correct in that exposed foam is a no-no according to code and to common sense. Even if it does self extinguish in the absence of flame (which not all foams do but most used as home insulation will) it still makes no sense to expose foam.. first I don't know of any that wont degrade when exposed to UV lite (sunlite) second why increase the amount of smoke any fire is going to put out? I mean if your house is on fire the couch and other things will emit plenty of their own nasty smoke, why add your insulation to the mix?
PS I think in a real fire most insulation burns and emits smoke. I know that fiberglas does and I've seen homes insulated with Celluliose that have burned to the ground and there isn't a pile of ground up newspaper where the walls were..
Idaho, I was kidding around about the cave look in my earlier post. Fire-resistant or not I would always cover it whenever possible in general, and certainly if it was a code requirement to do so.I was reassured by my "torch test" that the 2-part polyurethane product (the Tiger-Foam) I have been using wasn't going to create a fireball inside the wall cavity or in my attic.Personally, I would try to avoid any building material that would burn like a styrofoam chest! Too many wall penetrations and wiring to worry about.
I don't find the poly foam any more flamable than most other construction materials like lumber, maybe even less so than plywood and osb, but I do hae some concern that when it does burn the gasses are more toxic.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Find a foam supplier who has done the testing and has a class A fire / smoke compliant product. Ask for a copy of the test for the code officials. Do not take the suppliers / installers word for it that the product meets code. Our product of choice can be installed anywhere in a residence if it is covered by a 1/2 DW or equivalent fire barrier. Likewise it can be installed up to 10 1/2" thick in and attic assembly on the underside of the roof deck and left exposed. Knee and gable walls however require an ignition barrier.The only reason these applications work is because the manufacturer paid to have the product tested and it passed. The test and application are product specific. Just because one brand passes this test does not make it applicable to any other product. Check with your local code offical and the manufacturer of the product you are planing on having installed. This ruble foundation sounds like a perfect use for the right product even if it need to be protected with a fire barrier paint or similar product.Garett
wodroe,
could you please explain where your climate is?
I keep thinking in terms of my climate and here moisture wants to get out, if it can't get out thru the foam (which it can't) then it will go thru wood. Since wood is hygroscopic, that is it absorbs moisture from the air.. damp wet wood is not something that I would like to see..
But maybe where I am is differant from where you are so we need to build differantly.
Hey Frenchy, I'm in the the dry climate about 10 miles East of you. Seriously, moisture absorption in wood surely does occur, we can see it in the seasonal movement of wood everywhere. While wood will absorb moisture, it will not absorb enough through vapor pressure to be a problem.In the winter, because we have higher inside humidities, the moisture wants to get out, but when we get those summer temps in the 90's and dew points in the 70's, and we air condition with cool dry air, the moisture is moving in.
woodroe,
Yes, I concure! Did it seem like I wasn't in agreement? Stop by sometime!
"Stop by sometime!" Tomorrow is Saturday, I'll be there at 9:00 for brunch, but only if you aren't cooking the hash browns in WD.