Proper Insulating Roof Ceiling

Cathedral ceilings must provide space between the roof deck and home s ceiling for adequate insulation and ventilation.

Proper insulating roof ceiling.

For example cathedral ceilings built with 2x12 rafters have space for standard 10 inch batts r 30 and ventilation. When tom insulates a cathedral ceiling or a finished attic he also turns to foam. Illustration by ian worpole. The right way to insulate attics and cathedral ceilings with batts using certain t.

An advantage of spray foam is it s quick whereas foam board needs to be cut and measured which can be a chore. But its open cell structure still allows moisture to escape. Set up a stepladder tall enough to work comfortably from. If you re insulating the roof directly.

The standard width for joists is 24 inches. This can be achieved through the use of truss joists scissor truss framing or sufficiently large rafters. To insulate the roof itself you either use spray foam or retrofit with it with rigid foam board. Always cover the tops of the ceiling joists to make sure the insulation is deep enough to reach your target r value and to prevent thermal bridging the heat loss that occurs through the wood framing.