Roofing Foam Board

If you want to install rigid foam above your roof sheathing in climate zone 3 then 1 2 inch of rigid foam board is not ideal this rigid foam layer needs a minimum r value of r 5 and that s impossible with 1 2 inch of foam.

Roofing foam board.

Attach to deck board. Some parts of the country necessitate a vapor barrier under the rigid insulation however this wasn t necessary in our case. The panels need to fit together tightly to help prevent warm air from leaving the top of the building. For new construction use rigid boards to insulate slabs and the outside of foundation walls.

For a basement remodeling project consider insulating basement walls with foam board. To attach the insulation you can use screws with large washers a special adhesive made for adhering foam board insulation or for smaller pieces you can seal them in with caulk or spray foam. Foam board insulation is easy to cut with a circular saw with a masonry blade or scored with a utility knife and snapped like you would drywall. After the roof deck is prepared the rigid foam boards need to be cut to size to fit snugly together on your roof.

Composed of a closed cell polyisocyanurate foam core bonded in the foaming process to retroplus roof board on one side and a glass reinforced facer on the other. Rigid foam is produced in various size panels 4 ft x 8 ft 4ft x 4ft etc. Rigid roof insulation board. As my article states you need a minimum of about 1 5 inch of eps 1 inch of xps or 1 inch of polyiso.

Use a premade kit for this type of project.