Insulating a Maine Roof with Dense-Pack Cellulose
In Portland, Maine, Dean Manoogian is pondering how to insulate the roof of his Cape Cod-style home. It’s been constructed without gable, soffit or ridge vents, and Manoogian’s plan of attack is to attach 2 in.-thick sheets of rigid foam to the bottoms of the rafters and fill rafter bays with dense-pack cellulose.
More from greenbuildingadvisor.com
As he explains in a Q&A post at GreenBuildingAdvisor, the rub is what becomes of water vapor that migrates through the insulation in winter. Without a means of venting the moisture to the outside, the roof may be a victim of condensation, mold and decay. To forestall the possibility, Manoogian wonders whether a peel-and-stick membrane should be applied to the roof sheathing and rafters before the rest of the insulation is installed.
The vapor-impermable membrane would presumably keep moisture away from sheathing and rafters. The city has already approved his plans, but is he on the right track?
That’s the subject of this week’s Q&A Spotlight.