I’m considering Structural Insulated Panels for my new home in So. Maine. This building technique is new to me, I’ve read a little on the internet and in FHB, but have never seen one up close. Sounds (especially the speed part) too good to be true. Would those with experience, thoughts or tips care to offer comments or advice?
If you have built with SIPs would you care to weigh in on polyurethane vs expanded polystyrene core?
Thanks
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I built a timber frame with SIPs, and yes, they save a lot of time......If you know what you are doing with them. If this is a one time project for yourself, I would contract it out. You will not likely save any time on your first try, and you'll probably have to hire a crane truck if you are using panels of any size. I could have stick framed the exterior walls for less money, but the energy efficiency is the real reason to use them, IMHO.
As for polyurethane vs polystyrene, I have heard that the polyurethane carries a higher R value, but at a greater up front cost. My local SIP guys didn't carry polyurethane at the time, so there was no real decision to make. I think even the polystyrene blows away stick frame for true R value, anyway.
Jaffo,
I built using SIP's I did it myself because the contractors I talked to were all trying to sell me stick building.. Once I got the hang of it things really are easy..
There are a couple of tricks you'll figure out yourself and if not I'll gladly talk you through it..
I really love the energy efficency, less than half the cost of the previous well insulated stick built house.. in spite of many more windows and a much bigger space!
Jaffo,
I am building my own place using SIPs. Here they are the day they arrived at the site. Most window openings can be precut at the factory and all the openings were right on and all sills were level. We used polystyrene only for bump-out floors where the 10" panel thickness gave the required rigidity. You can do a lot of your research at the panel manufacturers web sites, e.g. http://foardpanel.com or http://winterpanel.com where they post good technical information.
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I remember you posting in here with a leak ofsome sort in your roof, did you ever locate the problem?
butch,
It wasn't a leak, rather condensation forced it's way past the seal at the peak of the roof, and soaked the bottom layer of osb.. Top layer of OSB was bone dry.
I'd planned on putting a heat recovery system in and this is one more reason to do so.. that will suck up moisture and prevent a reoccourance.
If your interior RH is REALY 5% as you claim an HRV system is not going to solve you problem.
Bill,
It is, however when cooking in the kitchen which is part of the great room vapor comes from cooking, washing dishes etc. and etc.. a heat recovery unit would draw that vapor from the peak and put it into the HRV in the basement.
I could use a vent hood but smells from cooking are never a problem only the water vapor.
Are you using any solar gain in the energy design by either venting the hot air in summer (if direct sunlight actually falls on the interior in summer) or recirculating it in winter by collecting it at the highest points and moving it to the lower areas? Did your SIPs have provisions for running either high or low voltage wiring?
"I cut this piece four times and it's still too short."
highfigh,
Yes, I designed the house with a great deal of concern for natural solar gain, however I was limited because the dominate views were to the north, east, and west. My southern view is obstructed by my neighbor. In the winter I've planned for a heat recovery unit (not yet installed)
However I was shocked at just how efficent the panels are.. with the aide of a digital thermometer I found the tempurature at the ceiling 28 feet up was within a 1/2 of a degree of the tempurature of the floor.
They offered wire chasses anyplace I wanted them but I found it much simpler to make my own.. That way if I forgot something it was no big deal to put it in after the fact. I simply bought a few cheap spade bits and a handful of extensions and it was easier than cutting warm butter with a sharp knife.
The great thing is once all the panels were up and I suddenly realized that I didn't have power to the billard room I was still able to retro fit it.
I'd never put water in an outer wall but if I needed to I could have just as easily by simply using a bigger spade bit..
What is the square footage of the house? How open is the basement to the first floor- is there a wide open staircase or does it have a door?
"I cut this piece four times and it's still too short."
Total sq.ft. 5300, That doesn't count the 900 sq.ft of attic which currantly is set up as a ping pong room.
The "basement" is open to the second floor and by extension all the way to the roof..
I have a walk out whereby you enter the main floor from the "basement" floor. that opens directly into the great room with it's 28 foot ceilings.. Since I have 9 foot basement plus a foot of floor thickness (actually 16 inches) the total is a little over 38 feet from the peak to the driveway..
Right now everything is wide open but I do have a set of double doors to install That way I can isolate the open entry door from the rest of the house. The double doors will be down near the entry door to provide a modest size thermal lock. They aren't going on untill nearthe finish point.. too much of a hassle bringing things thru two sets of doors..
In relation to polyurethane vs polystyrene, polyurethane wins hands down. I am in the process of building a research house using the polyurethane panels built by Emercor. We have looked at so many options before we can to this descision, but I won't bore you with that. You can see what I am doing at http://www.factro9.ca . One suggestion I would make is that if you do choose any type of sips panels, get them with osb on inside and out and not drywall on the inside. The little extra work of installing the drywall after will be worth it in the long run, especially if you ever need to remove a sheet of drywall. Good luck on your project!
My panel contractor used osb faced panels (both sides), but screwed drywall onto the panels before installing them over the outside of the timber frame. This eliminated much of the challenge of having to finish drywall which had ben butted up to the timbers.