Cathedral Roof Insulation Details

This type of construction is also structurally sound and.

Cathedral roof insulation details.

This not a code requirement but ought to be only 1 inch is typically specified. The side exposing the kraft paper must face downward. Cathedral ceilings on the other hand traditionally feature straight sides that slope upward at the same angle as the exterior roof line. There must be at least 1 inch 2 54 cm of space beneath the roof s plywood sheathing.

Cathedral ceilings built using 2 x 12 roof rafters allow enough space for the fiberglass batt insulation and a 1 5 gap for ventilation. Johns manville aptm foil faced insulation sheathing board is an excellent choice for insulating attics and cathedral vaulted ceilings. Here are some older home cathedral ceiling roof insulation and ventilation options that you may consider. At insulation location for cathedral ceilings we describe a high labor method that combines providing an air barrier above fiberglass insulation in a cathedral ceiling to avoid heat loss by air movement in the roof combined with the addition of solid foam insulation to provide a much higher r value for the completed cathedral ceiling structure.

Reduce under roof insulation level to 3 fiberglass r 11 under the cathedral ceiling not good energy savings not recommended but functional just poor insulation value. Pa302 2 ceilings without attic spaces n1102 2 2 r402 2 2. When applied to the. This will ensure adequate airing.

Press the kraft faced insulation batts between the joists. Where the design of the roof ceiling assembly does not allow sufficient space for the required insulation such as cathedral ceilings the minimum required insulation for such roof ceiling assemblies shall be r 30. Once this happens the water drips into your insulation or soaks into the roof sheathing. Hot humid climate all metal cathedral roof must use r 11 batts incredibly helpful 5 thread.

This type of roof assembly is designed so the air can flow up the soffit vent through an insulation baffle pass through the 1 5 gap between the insulation and roof sheathing then exit through a ridge vent. So if you must use fiberglass insulation batts and you dont have access to spray foam or closed cell boards what do you do. In vented cathedral ceiling assemblies a minimum 2 inch clear airspace is recommended between the underside of the roof deck and the top of the cavity insulation. Vented ceiling across rafters.

Polyiso provides one of the highest r values per inch of any rigid insulation r 6 at 1 inch.