I am building a bungalow with ICF foundation/Basement and SIP walls and roof. There was a problem at the plant that makes the polyurethane panels- the press was down, they say.

The wall panels were delivered with voids in the foam- not all the way through, but substantial, with some of the studs pulled away from the foam. The vendor says he will send out a crew to foam it in. Will this be sufficient to obtain an adequate vapor barrier, or should I poly it?

The roof panls are more problematic. They have OSB skins both sides, as opposed to the walls which were OSB outside, unfinished inside so the foam is there for all to see (including defects). There is no way to visually check the roof panels. The vendor  said he will wait until there is some heat in the place, then take a look with an IR camera to see if there are any cold spots 9it's minus 20 here...). From what I can gather from IR cameras, voids the size of your fist MAY be visble, but smaller ones may not. Again, what about the vapor barrier aspect  and air infiltration? Do I poly the roof out of fear?

bob

I would reject the entire order , it sounds like a lamination problem. Or have the manufacturer hire an engineer to certify that the field foaming is adequate

Bob,

Usually, at the manufacturing plant, the polyurethane foam is injected between the two wood skins under considerable pressure and, when hardened, produces a strong bond between the foam and the skins. Now, if there were a problem with the press or the foam, I would suspect that the supposedly strong bond might not be as strong as it’s supposed to be. And when you mention voids, I really start to suspect the quality and structural integrity of the panels and the energy efficiency of the foam. This is certainly not what you paid for or expected from their advertisements. I would read over their contract and warranty very carefully and might even retain the services of an attorney. This isn’t about a washing machine that’s not working right. This is hundreds of thousands of dollars you’re investing in your home that may have inferior walls and roof. I think that you’re correct in the idea that they are going to miss some voids, reducing the thermal efficiency of your home. Are you willing to pay for their manufacturing errors for as long as you own your home in higher heating and cooling bills? Personally, I would let them know that I was a very unhappy customer.

As far as the roof goes, I like to cover the whole roof with ice and water shield, putting a barrier between the OSB and any moisture. Make sure all the interior SIP seams are sealed to prevent condensation forming in the seams.

Steve
GrandCountySIPs.com

Bob, it sounds like your panels were severly "under blown." I'm assuming the roof panels also have studs between the skins, if not you will see some deformation in the panels and definitely a loss in insulation value. If that's the case I would not accept the roof panels.

That aside, I'm interested in the concept of the foam being considered a vapor barrier. Do you have literature to back that up? Does this mean that you won't need to use a house wrap such as tyvek?

Ted,
Both EPS and XPS foam are closed cell products that are not only moisture resistant, but air infiltration resistant. But, it's still a good idea to put a vapor barrior on the exterior to protect the OSB from moisture to maintain the integrity of the OSB(if you're using OSB laminated panels). For example, you can put water in a styrafoam cooler, and as long as it's not cracked or otherwise broken, the water will stay in there indefinitly.

Steve
GrandCountySIPs.com