Vaulted Ceiling Insulation Rigid Foam

We are planning to use r30c insulation which is denser for cathedral ceilings.

Vaulted ceiling insulation rigid foam.

Do no use a vapor barrier under the. I bought an old ranch on long island climate zone 4 with no insulation and i vaulted the living room and den ceiling they are next to each other. Rigid foam boards used in ceiling insulation are often made of either cellulose fiber fiberglass polystyrene or polyurethanes. The terms refer to whether the foam bubbles burst during curing making the foam soft like a sponge or remain intact and firm like those in the rigid foam panels at home centers.

Regular ceilings are likely to be under. Polyiso provides one of the highest r values per inch of any rigid insulation r 6 at 1 inch. We re roofed our house this summer and found a lot of damage over our family room with a vaulted ceiling. Seal the insulation or the ceiling surface below against air leakage.

We replaced the plywood and are now redoing the underside. How to attach rigid insulation to ceilings. Rigid foam also can be installed above the roof sheathing in tandem with air permeable insulation between the rafters. Place the insulation between the rafters or below them.

Insulating a vaulted ceiling is similar to insulating exterior walls with one notable difference. The roof has a roof ridge vent and ventilation holes in the soffits. Code specifies the minimum r value of the rigid foam layer. Rigid foam on roof sheathing with air permeable insulation between the rafters.

Attics and cathedral vaulted ceilings. Thin metal or rigid foam the baffles. Vaulted ceilings require venting as well as insulation. Johns manville aptm foil faced insulation sheathing board is an excellent choice for insulating attics and cathedral vaulted ceilings.

I have a dilemma. About the only time you are likely to add rigid insulation to a ceiling is in a retrofit of a cathedral ceiling. The roof rafters are 2 x 6 i was planning to do 2 inch rigid polyiso super tuff r back to back in the rafter bays with foil facing the interior. You don t want moist air leaking into the roof cavity.

This approach relies on a near perfect air and vapor barrier on the house side of the ceiling cavity to keep moist household air and water vapor out of the roof cavity. While it is possible to use a permeable insulation open cell foam fiberglass or cellulose in an unvented cathedral ceiling it is risky. When applied to the. We are creating on site baffles with 1 rigid foam boards.

In this case the rigid foam can be thinner than when it s used alone. Closed cell foam ceiling insulation in a vaulted ceiling offers substantial advantages over open cell.