I’m currently working on plans for a new house in a year or so, and I’m curious about SIP walls. I guess I’ve just always been used to stick framing, but the potential for energy savings has my curiousity high despite not understanding the workings of SIPs
A few questions
What do I have to have under it to support it? I’d rather go with traditional floor trusses, is that ok to use?
Can I just do the SIP wall panels, and do conventional trusses? The few SIP jobs I have seen are all vaulted ceilings (Which I think is a waste of space)
Wiring – how the heck is it done?
Finishing – I’d sure as heck hire somebody to handle the install, but how easy is it for Joe carpenter to finish out the house after the panels are up?
I’m sure I’ll think of other questions, but that is what I am curious about at this point in time.
Replies
Hi,
We're building an SIP (Insulspan) house right now. We used a Superior Walls foundation--which our SIP builders favor because you're guaranteed to get a foundation that matches up with the factory cut SIP's (out of whack foundations are much harder to deal with when using SIP's). The rim joist and I-beams go on top of the foundation, then the SIP's are set on the deck. I'm sure you could use floor trusses instead.
We're using trusses on top of the SIP walls. The panels are more expensive, and we can get a better R-value from blowing lots of cellulose up there.
There are wiring chases drilled out at outlet height and switch height, so the wiring can be fished through them that way. They can go up through the basement or down from the attic to get around obstacles also. The foam can also be drilled out on site if something needs to be changed. You definitely want an electrician who has some experience-you don't want your house to be their guinea pig.
I guess I'll let you know how it is to install the siding in a couple of months after we've done ours. The only real issue is the lack of studs to nail to, there was a recent discussion about this if you want to search for it. Hanging drywall should be a piece of cake--no studs to try and hit.
We love our SIP installer--they're doing all the rough framing as well. You definitely want someone who is detail oriented. Hopefully you'll find a good one near you--and they can probably recommend electricians who they've worked with before.
Have fun researching,
Jo
Something to think about, maybe you already have and chose not to follow that route:
If you frame your first floor box in a few inches on the sill and run your panels down onto the sill, outside the rim joist, you get a better insulated shell.
Also, on timber frame houses you can attach the sheetrock to the panels before installing them, that way you don't have to butt them up to your frame on outside walls. On a regular sip house, it probably wouldn't make any sense to do it.
Are you satisfied with the sound attenuation properties of your SIP product? I am a little concerned about STC (sound transmission class), numbers for SIP's. I have heard they are almost acoustically transparent.
Any thoughts?
I don't have any scientific numbers for you, but our house is on a busy lake that's has a lot of boat engine noise in the summer. Even with a wall of windows on the lake side, once the walls were up and the windows were in, we couldn't hear the noise.
Leigh
I am a domestic goddess! I deserve three ovens (and two dishwashers)! I am a domestic goddess! I deserve three ovens (and two dishwashers)! I am a domestic goddess! I deserve three ovens (and two dishwashers). . .
Check this out (about 1/3 of the way down the page): http://www.animallab.com/articles.asp?pid=20
Has to do with animal testing labs, but it does discuss SIPs' sound attenuation properties.
Leigh
I am a domestic goddess! I deserve three ovens (and two dishwashers)! I am a domestic goddess! I deserve three ovens (and two dishwashers)! I am a domestic goddess! I deserve three ovens (and two dishwashers). . .
So, as I understand it, you are using SIPs for just the exterior walls. Right?
And you have a conventional floor deck structure sitting atop your foundation, and then an engineered truss package for your roof structure above. Right?
So, the benefit you have over a studframed house is the insulation factor in walls, insulation is already there, plus speed of installation. Right?
Did you do all the math to show exactly what your cost premium is from doing this?
I ask because I am about to go through this exercise. I stickframed a house, a client wants a copy of it built on his lot, but wants the wall framing done either panelized or with SIPs.
I can calculate exactly my material costs for the stickframed walls, plus labor to erect, plus insulation. I'll compare that to the pricing I get from Insulspan and Harvest Homes (panelizer.)
Yes, that's right. Only the exterior walls are SIP's. We didn't do the math to compare building costs. We didn't want stud walls, so it seemed like it would be cruel to have a builder give us a quote just so we can see the difference.Time-wise, I'm not sure it actually saved a lot of time. I'm sure a fast crew of framers could have put up stud walls in the same time frame. They nail down 2x6's around the perimeter of the floor deck, then tipped the panels up into place, secured them to each other, braced them--and maybe a few other things I missed. Looking at my calendar, it looks like it took 3 days to put the first floor panels up (1100 sq ft, 12 outside corners), and 3 days to put the second floor panels up (900 sq ft, 8 outside corners). There were 2-3 men installing, one man operating the boom truck. I can tell you how much our panels cost (20K), but that probably varies regionally, what the house plans are like, and I have no idea if that includes a mark-up from the builder. It did include the design time (taking our plans and dividing them up into panel-sized pieces).Hope that helps some, I'm just the HO, so I don't have many more details.Jo
We used SIPs to enclose our timberframe, so the situation isn't exactly like yours, but here's what I learned:
First of all, get this book: Building With Structural Insulated Panels (SIPs) by Michael MOrley. It's pretty much the only one out there, and answers a lot of questions.
http://www.taunton.com/store/pages/070482_tcpg.asp
We used conventional floor trusses, no problem, with an Advantech subfloor on top.
We used SIP roof panels, so I'm no help on your second question.
Our SIPs are an OSB/foam sandwich and came came with wiring chases built in, based on the plans we sent them. The electricians still hated us, but that had more to do with the timberframe than the SIPs (running wire through those wasn't hard, just different from what they're used to).
Our GC's regular carps did all the interior framing and finishing. No Problem. Again, the timberframe offered more issues than the SIPs.
Leigh
Also check out this site:
http://www.sipweb.com/learningcenter/default.asp
Leigh
I am a domestic goddess! I deserve three ovens (and two dishwashers)! I am a domestic goddess! I deserve three ovens (and two dishwashers)! I am a domestic goddess! I deserve three ovens (and two dishwashers). . .
SIPweb is the site that I came across the charge of acoustic transparency. I'm wondering what the experiences are of those who live in them them, or what measures were used to handle sound issues.
Have a Timberframe wrapped in SIP panels, not on the lake but overlooking the lake, sitting on outside decks you could hear boat traffic but inside NO noise unless doors and windows are open.
See my post above--our new house is on a busy, noisy lake and with doors and windows closed, no noise.
Leigh
I am a domestic goddess! I deserve three ovens (and two dishwashers)! I am a domestic goddess! I deserve three ovens (and two dishwashers)! I am a domestic goddess! I deserve three ovens (and two dishwashers). . .
SIP Issues
We recently moved into an energy tight house that is log/timberframe and SIP construction. It is extremely energy efficient and does great in high wind conditions (we had almost 100 MPH winds there yesterday and although outside it was extreme, the house doesn't shake or anything). The issue is the acoustics - you can hear right through the walls. Soon after we moved in we discovered we were in an unpublished en route flight path that was not disclosed to us. Despite sleeping with wax earplugs, and white noise maker and sleeping in a lower floor bedroom, the jets sometime wake me up 5-8 times per night. And this is in a mountain setting on 4 acres, where otherwise there is not much noise. If I was building a SIP home I would look into a double SIP wall with an air gap/sleepers in between the forms. This would capture/deaden outside sounds. Otherwise the sound deadening is not significant - maybe 20db outside to inside on our noise meter. It has been a disconcerting experience in an otherwise beautiful house.
If you make an effort to not let the aircraft noise get on your nerves, you'll find that, in a few months, you don't even hear it.
SIP noise & the entire cost
Our SIP home was supplied through AmeriSus they provide the design, the SIP's and everything else that makes up the house including all systems, fixtures and finishes all the way down to paint and doorstops. We are on a busy street and the SIP's block out all exterior noise much better than other stick built homes in the neighborhood. As far as interior acoustics we have three floors totaling about 1500 sq ft and the house is pretty quiet especially considering that all our floors are bamboo. I can't understand some ofnthe issues described by others and would have to believe from our experience that they are not SIP related.
Repair to SIP panel house
We just repaired the exterior of a SIP post and beam house here in Cape Ann, Mass. We had to replace the bottom part of the panel at various places which had been compromised by rot in the OSB sheathing and animals had made homes in the excavated cavities inside the panels. The panels were resting on a 1 X 12 mudsill and the posts were bearing on the sill as well. We had to cut out sections of the wall outside the first floor joist and rebuild them with 2 X 6 stud boxes filled with five inches of Dow styrofoam and plywood sheathing. Since the inside of the SIP panel is 1/2"drywall it turns to mud and holds moisture.
We also had to remove two six foot double doors and frame one opening for a wall and the other for a double window, We used the same frame replacement scheme for the rot below the old doors. The two factors which destroyed the OSB sheathing is the deck built against it which did not have proper ledger flashing. The second issue is the roof drip on to the deck which again added water to a poorly flashed deck on the North side of the house. I'm afraid to say there is more rot at deck level that we can't get too behind the deck framing. Another observation is that the doors and frame failed to keep the moisture away from the interior of the SIP panel. All and all it is a poor situation with a deck butt up against the panels. OSB is like a sponge. Good drainage modern pan flashings at door and window openings and good ledger flashings are key to protecting the base of the SIP structure.
We now use pvc water tables at the base of all the walls we renovate since we can flash the base of the wall with butyl sticky flashing and then drip cap above the horizontal starting trim. The siding is protected from moisture and the wall is easier to repair in the future. As a renovators, we are respectful of the job of the next carpenter who may have to fix the wall, whenever.
Repairing these kinds of structures is not easy since there are no studs to nail replacement sheathing to. Be very careful on the flashing details and you may avoid these issues.
Inside of sip panel is osb typically.
When was the house or sips built/installed?
Typically the interior of a sip is osb not drywall, though you'd have drywall fastened to the inner osb. Was this not the case in your repair?
Is OSB really any different than plywood. Particle board is like a sponge. OSB should be as good as plywood in terms of water repelling.
Thanks for the post, Interesting to read.
bg
I recently built an SIP home here on the gulf of Mexico where wind codes are restrictive and cooling loads extreme. SIP was my choice due to strength and energy effeciency of the envelope. Older sip type construction had issues with OSB ply that was not treated for rot and SIP design was not readily adapted to older local building codes. My home was the first SIP in the county and the electrical inspector actually shut us down because he could not see the rough in wiring. It was quickly resolved but indicitave of the issues we faced with older inspectors not familiar with SIP construction methods. The actual home construction was completed in 90 days from bare pilings, (this is an elevated home 18' above mean sea level), to a CO and move in. The home is 2200 sq ft, basic hip frame roof, and no fancy dormers or wall angles. As a former contractor I estimated the framing segment 25% quicker that stick framing. If stick framing is done to equal the insulation level of the SiP home it would be as expensive. This system was set on a traditional floor framing system with a triple lamated LVL rim joist and a 6X6 cut vertically every third panel with a 5/8 galvanized rod through bolted in the LVL rim joist. This house is designed to withstand a 200 mpg gust.
Heating and cooling is accomplished with a highly effecent heat pump and the home is all electric except the kitchen gas range. My electrical bills average $100.00 per month over the year. Sound proofing is excellent verses a frame home and I cannot hear cars passing on the street. The biggest disadvantage of SIP construction is electrical. We decided to drill vertically at every plug in to wire around the perimiter of the home. This was a bit more time consuming but worked. Even with the existing preformed channel this was quicker given the feed circuits. I would note that we did our own wiring and a good electrican would probably have a better method. It is my opinion that SIP has proven more cost effective and more energy effecient than frame construction in this particular area. Any home I build in the future will be SIP.
The reply from sailorman says it all. I am a GC who worked for HFH in Ont Canada, we built several homes with SIPs and without getting into alot of construction details (which have been discussed already) all I want to add is that we build with volunteers and the ease in which the exterior walls go up is hands down faster and more acurate than stick frame const (considering we work with non const minded volunteers).
We build single story homes sothe electrical is simply fed up the exterior wall in a chase that leads to a cut out with a 4" dia. hole saw which is later filled with a foam gun after the wires are pulled.
n
SIPS Construction
I too recommend purchasing the book on SIPS construction. It has excellent photos on all phases of SIPS construciton and some great details. Speaking of SIPS details, most of the SIPS manufacturers can and will provide you with CAD details on all the different types of SIPS connections to foundation, floor and roof systems. Manufacturers also provide shop drawings (CAD drawings) showing the numbering and exact placement requirements for all the panels for a project.
Regarding running the SIPS all the way to the foundation wall sill plate, this is a great idea providing you have considered all of the following:
1. Absent an exterior floor system extending to the outside of the walls, you will not have a place to conveniently attach an exterior deck ledger to (i.e., you won't have a rim board), if one or more decks are called for on any such walls for your project. You could, however, still have a deck installed, but it will need its own load bearing system installed independent of your walls (free floating so to speak).
2. Make sure you have considered how all of your electrical and plumbing will be installed around the perimeter of the building as it is a bit more involved to accomplish this work for any systems that need to be imbedded in the walls.
3. Make sure that you will have adequate bearing area on your foundation sill plate for your floor system (solid wood joists, engineered I-joists, engineered floor trusses, or ???) to rest on. This may require as little as 1-3/4" bearing but more might required ... you need to verify this with either your design professional or the floor system supplier. If you can't provide adequate bearing "depth" for the floor system to rest on, then you may need to consider thickening the foundation walls and sill plate or other alternatives.
Make sure you learn about the different ways of dealing with plumbing drains and vents, regardless of where you place the bottoms of your SIPS walls. Depending on your building's design, you may have to deal with this issue, such as where kitchen sinks are located along exterior walls. Your SIPS representative will be able to help you figure this stuff out. You should also verify the code requirements as well for any plumbing that you want to install in exterior walls.
My wife and I built our house with 6" SIPS (main level) on ICF basement foundation walls. My son was working at the area InsulSpan factory so we were able to get a little bit of a price break for our SIPS panels through him. We ordered the wall panels no longer than 8' so that we could manually handle them (two people), thereby eliminating the need to rent any equipment. We were able to get all the panels up in one day. Our house is a conventional 52' x 32' ranch so we only had four corners to deal with. Keep in mind, however, that wall panels can be made as long as 24' with single sheets of OSB ... that is how long they can get them. You will need some equipment (or lots of big football players) to lift the longer panels as they do get heavy.
We did our own wiring (before I purchased a wire puller) and I had a little bit of trouble snaking the wires through some of the walls ... always where the studs are buried in the wall panels at the sides of window openings. Where I had the trouble was where the holes in the imbedded 2x's (3" thick to carry the window headers) didn't perfectly line up with the holes "burned" in the foam cores. In a couple of those difficult areas, I actually just bored a hole into the problem area to gain access to the ends of the electrical wires so I could push them through the vertical framing.
Another small detail to think about regarding your SIPS wall panels is where you want your ceiling height to be. If you only do the typical 2x bottom and top plates and you're using standard 8' tall panels, then you will end up with a 96" rough ceiling height (subfloor to bottom of trusses). The problem with going this route is the sheetrock dimensions. Whether you install the sheetrock horizontal or vertical for an 8' ceiling height, you may have a difficult time installing at least some of the sheets. On page 81 of my copy of Structural Insulated Panels (2000 edition), there is a picture showing the installation of a "double top plate" which allows for more ceiling height and eliminates any potential problems with installing the sheetrock on the SIPS walls. The picture caption also states that the installation of the double top plate almost doubles the bearing capacity of the wall. Maybe this would be a necessity for anyone building with SIPS in areas with heavy snow loads.
The electrical switch and outlet boxes we used were the remodeling type with the rotating wings. To install them requires the removal of a bit of foam from the inner side of the panels so the wings have clearance to rotate. They have performed satisfactorily accept for one high use outlet which I need to pull the cover and re-tighten. You will need to remember to seal up all your SIPS penetrations after your electrical, plumbing, etc. is installed. The vertical and horizontal wire chases cut in the foam can be interconnected so if you miss plugging one up, you might feel a bit of air movement next to an switch or outlet when the wind is howling outside.
I have never used SIPS panels for a roof so I have no practical experience with using them for that application. I do know that you need to get all the installation details right (panels tight together and properly sealed/adhesived together) or you could have future problems with your roof, especially if you don't properly handle humidity and ventilation within the home or building. There were some lawsuits as a result of construction installation and/or product failure (sealants) problems with SIPS roofs in Juneau, AK some years ago which you can look up and research on-line. As with most types of construction, the devil is always in the details. If you don't get the details right (including dealing with indoor humidity), problems will be knocking at your door sooner or later. I am sure SIPS panels can be properly used for roofs; you just need to follow the manufacturers installation procedures carefully.
Our home has been very energy efficient. We are at about 3,000 feet elevation and our heating degree days is around 6,000. We primarily heat with a wood stove in the basement and burn about 2 cords of wood annually. We have good souther exposure glazing so that is quite helpful in the winter months, like today where the sun is reaching into our living room about 16' or so. I wouldn't say our SIPS home (upstairs) is the quietest wall system ... but, just like windows and doors can be our big energy leaks, I believe they are also our big noise leaks as well. If we'd used cellulose in our ceiling as opposed to blow-in fluff (fiberglass), I think our energy and noise performance would be better. If you are in a noisy area, I would recommend ICF's all the way to the roof.
Hope this information helps you with some of your decisions. Probably the best thing for you to do is talk to your area SIPS manufacturers and/or builders and visit some SIPS projects during construction, if that is possible. It is an excellent way to build and fast. You can't go wrong with good planning, a good design and using good installation procedures.