I recently was part of a whole house renovation and the homeowner had closed cell foam insulation done in the entire house. The roofing used on this project is a basic GAF Timberline series with normal underlayment. About a year has gone by and the roof in three different places is starting to bubble, all on the same slope and all apx. the same distance from the ridge. I have never seen this condition before and there are no nails causing this. Has anyone ever heard of or seen this condtion. I read somewhere online that sometimes closed cell if done to thickly can actually retain heat for long periods of time and possibly cause this???? Any help would be appreciated.
The impermeable roofing shingles stop any moisture in the OSB from drying on one side, foam stops it on the other- “Practical Recommendations”, pp.5, second and third bullet: http://www.earthane.com/ctu32e.pdf