Insulating Vaulted Ceiling Rigid Foam

R value insulation receives a rating.

Insulating vaulted ceiling rigid foam.

The roof starts with scissor trusses set on 8 foot centers. Spray foam closed cell is way out of our budget. About the only time you are likely to add rigid insulation to a ceiling is in a retrofit of a cathedral ceiling. Putting an addition on cathedral ceiling pitch is 12 12 with 2 10 rafters.

Advantages of rigid foam insulation under the roof. Insulating a vaulted ceiling is similar to insulating exterior walls with one notable difference. First closed cell foam has a 60 percent higher r value per inch than open cell 6 3 vs. These should have straightforward framing with no skylights and with direct access to soffit and ridge vents.

Vented ceiling across rafters. Kevin is working up the design for a new lakeside cabin in tennessee with plans currently calling for a scissor truss roof and a vaulted ceiling over the kitchen and living area. When applied to the. This is best for simple cathedral ceilings that are easy to ventilate.

Attics and cathedral vaulted ceilings. Husband wants to do rigid foam boards double and triple layer have a friend who takes used foam boards out of steel commercial buildings we can pick and choose our boards. Spray foam is a very expensive option however. He wants a trouble free roof assembly but local advice on insulation and air sealing has been hard to find.

In most cases however insulation will not help prevent moisture. A less expensive alternative is the more traditional vented cathedral ceiling insulated with fiberglass cellulose or open cell foam. The higher r value reduces condensation when moist interior air hits the now less cold ceiling vice versa in summer with humid outside air. Johns manville aptm foil faced insulation sheathing board is an excellent choice for insulating attics and cathedral vaulted ceilings.

Foil faced iso board can be cost effective insulation for finished attics and cathedral ceilings. Rigid foam board installation in the case of a cathedral ceiling involves installing three different layers that are each 1 5 inches thick according to the procedure discussed in this article appearing in fine homebuilding. The rigid foam layers are installed with staggered seams. Vaulted ceilings require venting as well as insulation.

Polyiso provides one of the highest r values per inch of any rigid insulation r 6 at 1 inch. Closed cell foam ceiling insulation in a vaulted ceiling offers substantial advantages over open cell.