Hi Michelle,
Yes, I think a better contractor would have helped, but the main issue I have is when the OAT is around 12F or below with an inside temperature at 68F (a delta of ~55F or more) I get heavy frosting on the exterior (cold) surfaces, in localized areas. Once we warm up this turns into a leak in some areas since the frost buildup melts and runs back in from the hole the air leaked out of. Or in some areas I have wet wood that never dries out because hot humid air is always blowing on it. Sounds easy to fix, just go find the air leaks and seal them, but not so easy since a small 1/8” gap that runs 2’ along a truss is enough to cause this problem and some areas are not accessible. I talked to an energy auditor and he said he has seen this before and thought that it could come from the wood drying and shrinking a bit and causing voids in the thermal envelope. He said he was impressed with the R-value of the foam, but he was still a fan of old fashioned fiberglass insulation. Contributing to this might be that my walls are also spray foam this exaggerates it since the house is very tight other than the small air leaks that are in the insulation.
I was told by my contractor and the spray foam contractor that this foam didn’t need a vapor barrier since it dries with a water tight skin on it. I also confirmed this with the city inspector, and he confirmed no vapor barrier needed. I would highly recommend using an additional vapor barrier.
Another issue I have is once you penetrate this skin on the foam it no longer has the vapor barrier qualities and the foam will become saturated and hold water. This became an issue when the electrician came through punching holes to run wires. Again if my primary contractor was doing his job, this should have happened since the timing should have been planned and coordinated better. I could go on, but I just wanted to let you know to ask around a bit more than I did.