Getting the Details Right for an Unvented Roof
How do you know when insulating your attic with spray foam is a good idea?
Writing in a Q&A post at GreenBuildingAdvisor, Storm is having second thoughts about his decision not to vent the roof. With the standing seam metal roofing already applied, it’s too late to add a layer of rigid foam insulation on top of the sheathing, but he wonders whether there are other steps he should consider?
Then there’s the question of the insulation itself. The three contractors he’s spoken with all agree that 6 in. of open-cell foam will be enough for this house in Climate Zone 4. Trouble is, that’s well below the amount of insulation required by code, and the plan raises questions about the risk of condensation on the bottom of the sheathing.
Those issues are at the heart of this week’s Q&A Spotlight.