Cathedral CeilingsWe are working on a remodel in northern California north of Eureka Ca, within a mile of the ocean. The roof is asphalt shingle (some day will add 4 inch’s of foam or a 4 inch sip and top with metal roof with air gap under metal maybe ) with a plywood underlayment. The next layer is 2×6 T&G fir that has a nice finish on it. With open beam exposed large 4×6 rafters holding them up. We want to add insulation to a small area in a studio kitchen on underside of ceiling ,. We are thinking 2 inches of foil backed rigid foam. We are planing in some firing strips on sides to screw the sheet rock to so they would be 2.5 inches thick.Which would leave a 1/2 inch airspace on wood ceiling between foam and wood .A small space top and bottom left open for air movement inside kitchen to allow air so no condensation on wood could occur. Is this the best practice vs foam tight against wood then sheet rock and no airspace which may make for moisture issues later?Whats the best practice?
We are working on a remodel in northern California north of Eureka Ca, within a mile of the ocean. The roof is asphalt shingle (some day will add 4 inch’s of foam or a 4 inch sip and top with metal roof with air gap under metal maybe ) with a plywood underlayment. The next layer is 2×6 T&G fir that has a nice finish on it. With open beam exposed large 4×6 rafters holding them up. We want to add insulation to a small area in a studio kitchen on underside of ceiling ,. We are thinking 2 inches of foil backed rigid foam. We are planing in some firing strips on sides to screw the sheet rock to so they would be 2.5 inches thick.Which would leave a 1/2 inch airspace on wood ceiling between foam and wood .A small space top and bottom left open for air movement inside kitchen to allow air so no condensation on wood could occur. Is this the best practice vs foam tight against wood then sheet rock and no airspace which may make for moisture issues later?Whats the best practice?
