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Spray foam shrinkage and substantial movement
 
Spray foam shinkage 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?

 

Posted on Tuesday, Sep 13, 2011 - 01:09:00 PM EST by  MAK
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