7 Best Of How To Install Rigid Foam Insulation Between Rafters Best Wallpaper JPG. Ventilated roofs require a 50 mm air gap above the insulation timber stop battens can be nailed into the side of the rafters to give the correct air gap when installing the insulation. Install foam boards with the foil side facing you.
The rigid foam board is usually about 050 a board ft. When installing the foam use caulk or tape for maximum insulation between the material and the board or floor. Feb 13 2002 Divide the space in between the rafters by 3 and then install the two strips according to your measurements.
Place some 1 x 3 blocks along the insulation to keep it in place without any bowing or bending.
Feb 13 2002 Divide the space in between the rafters by 3 and then install the two strips according to your measurements. Their spray foam quote sounds high 200 per board ft should be able to get closer to 100. Other Considerations To get the best performance out of spray foam insulation you must cover the roof rafters and surrounding areas as. Install the insulation so that it is flush with the bottom of the rafters but does not fill the rafter depth.