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Caleb DeFord
Posted: Oct 16, 2012 09:07 AM
Roof Sheeting issues with CC Foam
A contractor told me he heard of a cc job where the the foam went through the cracks in the roof sheeting, expanded, and visibly raised the shingles on the roof above.
I'm looking for some more info on this. Who can give me some examples of this kind of thing, and ways that the problem can best be avoided.
I already have my own ideas, but I'm open to anything that works.

Posted: Oct 16, 2012 10:11 AM
Rather than look for info to combat hear say, I would look for documentation about what the contractor is stating. I have never heard of something like that happening. There is no way that such a small amount of foam through a crack could move shingles, unless the foam contractor pointed his gun directly into the crack up close and let her rip, injecting alot of foam under the shingles. I have seen foam going through the cracks in a wall and getting under the tyvek before the siding was installed. This makes a small bump under the tyvek that is a pain for the sider to deal with.

Anthony Scarpelli
Posted: Oct 16, 2012 08:27 PM
Hello guys,

I just did my first spray foam job,(on my own personal house). It is a 1700 sqft 85% cinder block slab home with a room edition that had 1" fiber/foam sheathing and cement board simulated cedar exterior siding. It had been empty for years and we had mold so we decided to remodel it for my retirement home.

We ripped out the interior drywall and fiberglass to the stud walls and roof so that we can to do a full cavity insulation. We did the sealed attic. cavity fill Open cell with 4.5" around the walls 5.5" on the northern wall and still deciding if I should put 8" under the roof or 6".

This thread made me think of the foam that came out of the siding. No reflection on the foam, I knew that wall was way loose. We had a bit of foam come out of the foot plate on the edition so I know that was a big breeze hole before we started.
Caleb DeFord
Posted: Oct 22, 2012 03:10 PM
Thanks for your feedback, George.
The guy I talked to said he could show me the job he was referring to, so I might take him up on the offer.
I would imagine that there was a bigger than normal gap in the sheeting or something like that on the house he mentioned.
It's a good example of the kind of unexpected problems we can face on spf jobs.
Stay sharp and keep you eyes open.

David Lamb
Posted: Nov 08, 2012 08:36 AM
While possible such mistake can be prevented with proper planning and understanding of the product used. For example when spraying closed cell foam to the underside of a roof deck with 1" gaps between the rough cut planks you do a light 3/4" pass initially and allow it to cure. This will minimize or eliminate any unwanted push or expansion against the Ice and Water and/or felt. Picking an experienced, conscientious and certified contractor who is focused on quality and standing behind their installation tends to limit most problems with sprayed polyurethane foam.
mark moyer
Posted: Nov 12, 2012 06:42 AM
caleb...ive sprayed a gazillion shiplaps and ya never say never but,,,ive never pushed shingle or sideing,,(now celluluar collapse and buckleing,,lets talk..lol...or is it col??)
but man ive gone thru many ship laps and house wraps and roof membranes,,mostly with closed cell,,seems to push more,,but you knew that,,
but i tell the customer they got what they paid for,,the foam went to the leak and sealed it...dont let em push you in the application,,recognize the shortcomeing in the building envelope/substrate,,,and call em on it before you start shooting so the end result is clear and you pull out with a smile on your face or extra work in your job sheet...but you knew that,,,stay warm bro..

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