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Matt Brown
Posted: Sep 21, 2011 08:15 PM
Spray foam shrinkage problems!!!
We recently build a new home back in 2010. We had closed-cell spray foam sprayed on the ex terior walls, in the attic and on our ceiling. The foam was applied in temperatures probably averaging 75, with no excessively hot days or humid days during applications. This was in the fall months. On our ceiling we had applied 2" of foam directly onto the drywall lid and then had about 16" of dry cellulose sprayed over this.

When the spray foam was applied to the drywall ceiling we started having problems with the 5/8" thick drywall cupping upwards between the trusses that were spaced at 2' apart. The cupping was a substantial 5/8" difference. This was causing the drwall screws to pop and was causing the drywall seams to crack, that had been taped. We cut into the ceiling and found that the foam that had been applied to the ceiling was shrinking away from the trusses and pulling up on the drywall that it was adheired to, and making the drywall "cup" between the trusses where it was fastened. To head off the problem with the drywall we installed a metal channel directly over the drywall and applied a new drywall ceiling throughout the house.

We also had spray foam applied to an exposed wall that separates our great room from an unfinished bonus room. Within a month of the spray foam being applied in the attic and on this wall, we noticed some shrinkage of the foam on this exposed wall. This particular wall is a 2x4 wall framed with conventional #2 hem fir studs. A couple more months went by and we noticed still more shrinkage. We called the company that installed the foam and they came out and chinked the cracks where the spray foam had pulled away from the studs, where you could see the drywall on the other side. The separation at this point varied from 1/4" to 2" pulling away from the side of the studs and up to 3' in length-wise down the stud. We continued to monitor the situation and it appeared that it was not going to move much more. We were wrong....

8 months after the spray foam was installed we checked on this exposed wall that had been foamed. It was now in the middle of summer and our days were probably averaging 85 to 90. The foam that had been applied on this wall was now shrunk even more. It now had very obvious signs that something was very wrong. The foam had continued to shrink and pull away from the studs and also had begun to twist as it was shrinking and was beginning to pull away from the drywall on the finished side of the studs. The foam started out by filling a void of 16" wide by 3 1/2" thick between the studs. It had now shrunk down to a width of about 12" and a thickness of about 1 1/2". The length of the gaps are almost continuous from the bottom of the studs to the top now. The foam is hard to the touch and does not really give any when pressed on.

At this point in time we wondered if the foam that had been applied on our ceiling and exterior walls was doing the same thing. We pulled back the cellulose and found that the foam applied to the ceiling was still continueing to shrink even more. We cut into our exterior wall and found the same thing happening. The foam was shrinking and pulling away from the exterior OSB and the LSL TimberStrand studs that it was applied to. Again it is hard to the touch and does not give any when pressed on.

Has anyone ever seen or experienced anything like this? Does anyone know what is happening or why? Does this foam need to be removed? What should we do?
Terrance Harris
Posted: Sep 23, 2011 04:08 PM
Why hasn't your contractor gotten the foam manufacturer's rep out on your project when problems arose. The rep should be out there cutting samples to take back to his lab for analysis. If your contractor can't or won't get him out there, then maybe you can. Something very wrong going on here.
John Shockney
Posted: Sep 25, 2011 01:14 AM
I hope the contractor has good insurance

Terrance Harris
Posted: Sep 27, 2011 03:49 AM
I don't know why you are not getting more replys concerning your problems with your application. I recommend you direct your questions to Mason Knowles.
Bob Silverman
Posted: Sep 27, 2011 09:38 PM
I doubt the contractors insurance would help. They do not cover "your work" and they do not cover product failure. They would cover damage caused by your work, with the exception of mold of course. The real question becomes, "What it the damage to a home because the foam shrunk some?" We had a problem a few years back with a bad batch of foam and our insurance company wouldn't do squat! No, no, no, by the way, your next premium is due, we need it to help pay for our office party in Hawaii. You need to get the manufacturer out there to come and look at the job and see if they have had other issues with their foam. Of course they will tell you that you are the only one.

Good Luck,

Gerry Wagoner
Posted: Nov 28, 2011 04:58 PM
There are a couple possibilities here:

1) The contractor used a cheap foam and passed it off as a closed cell foam. 1.2# water blown foams can have this problem if the substrate is cold (doesn't sound like the case here).

2) The contractor may have added water to the resin side of the foam to make it go farther. I don't want to put thoughts in your head but it is possible anyway. That can make weird things happen in the dimensional stability department..

3) Off ratio? Again doesn't sound like the case if the foam is hard.

4) Sprayed too-much-too-thick-too-fast. This can cause minor foam retraction - but generally not the ongoing problem you are experiencing. (This caused the deflection in the attic.)

5) A problem at the manufacturer side. Have the foam tested extensively.

Good luck, foam is still the best insulation on the market and problems like this are unusual.


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