Aun Safe settled on spray polyurethane foam as the best way to turn his attic into a conditioned space. Although the open-cell foam between the 2×8 rafters would not be enough to get the attic to R-38, it was the best Aun Safe could do at the time.
“My question is whether I got what I paid for,” Safe writes in a Q&A post. The house is in the Southeast, between Climate Zones 3 and 4, where code requires attic insulation of R-38 and R-49 respectively.
The foam installer said there would be an average of 6 inches or 7 inches of foam in each rafter bay. But as Aun Safe explains, and photos of the job show, at least 30% of them are under-filled by 3 inches or more, meaning there is less than 4 inches of installed foam in those bays.
“I reiterate that this is not some small number of rafter bays,” he writes, “in which case I would just ignore it. It’s close to half of the rafter bays that have noticeable areas of significantly less than 6-inch foam depth.”
He guesses that the installers were just trying to save themselves the trouble of trimming back excess foam.
“Should I care?” he asks. “Is this reasonable? I simply don’t know what typical industry expectations should be for this sort of work, and I don’t want to complain unless a complaint is warranted (I am otherwise happy with the work that they did.)”
Does this fall within normal limits, or is it a problem that Aun Safe will have to pursue with the installer? That’s where we start this Q&A Spotlight.
There are two main types of polyurethane spray foam: open- and closed-cell. They are of different densities, have different insulating and vapor transmission properties, and they…