How To Insulate Under Roof Plywood

Cut styrofoam insulation to the correct size and layer it below the fiberglass already in place.

How to insulate under roof plywood.

Nail or staple the furring strips between the joists to hold the styrofoam in place. Lay the foam insulation face down. Plan to replace asphalt shingle roof with standing seam metal. Insulating a new metal roof step 1 install plywood or oriented strand board osb to act as structural roof sheathing.

Cut panels on roof. I live in charleston sc in an old 1858 3 story wooden house. Measure the length and width between two rafters in your attic and transfer the measurements to a 4 ft by 8 ft of rigid foam insulation board. Currently there is no insulation anywhere and the third floor basically an enclosed attic gets crushed by heat in the summer.

If 180mm is to be installed then 100mm board might be introduced between the rafters there has to be a minimum 25mm air gap between the insulation and the underside of the tiles or slates with an 80mm board running across the rafters. Leave gaps between panels. Transfer the measurements onto sheets of rigid foam insulation. With a warm roof the usual process is to split the insulation into two layers.

Lay the plywood perpendicular to the roof joists and fasten it in place using galvanized or stainless steel roofing nails. Measure the height of each sheet of plywood. Open cell spray polyurethane foam or closed cell spray polyurethane foam ccspf insulation can be sprayed along the underside of the roof sheathing to provide a conditioned and insulated attic space that can be durable and efficient in all climate zones see figure 1. Make all cuts to the foam panels on the roof for more accurate cuts and quicker placement.

Don t wet the plywood as it s. How to insulate plywood 1. Appreciate this extremely helpful blog. Rigid insulation under a cool roof in zone 3.

Clean the plywood by vacuuming away dust and debris or by wiping it with a tack cloth. Roll out the fiberglass insulation sheets between the joists facing side up making sure it is snugly in place. This reduces the need to go up and down the ladder for tools pieces of insulation and making measurements.