Spray Foam Insulation On Roof Rafters

R value of 7 in 1 inch 97 closed cell foam.

Spray foam insulation on roof rafters. When the choice is made to insulate along the underside of the roof deck spray foams have advantages over other insulation types because of the ability of spray foams to effectively air seal complex assemblies. But spray foam insulation used at the underside of the roof deck would need to be covered by a thermal barrier and intumescent coatings are commonly used. The spray foam can also serve as the thermal and vapor control layers in both new and retrofit construction. Lstiburek takes blame for bad language.

It s not coming from above the roof and it s not some new moisture source resulting from the spray foam. Class i e 84 fire retardant meets building code spec. Moisture generated indoors or that infiltrates into the home is responsible for the bulk of the moisture in an attic insulated with spray foam on the underside of the roof sheathing. Use closed cell foam it green for attic rafters.

Cathedral roofs especially need a lot more insulation between the ceiling and the rafters because there usually isn t any attic space. The movement of air into indirect conditioning of an unvented attic is a slow gradual process that will not be noticeable by occupants and typically will not put any strain on the hvac system. The best attic insulation. Heat from the house rises up to the attic but when there isn t one the heat rises up to the roof.

Polyurethane or polystyrene spray foams can provide thorough coverage to roof rafters and attic walls in much less time than is needed for other materials. In an uninsulated attic the heat passes through roof sheathing and disperses into the attic space. Spray foam insulation that s convenient and easy to use. Rigid foam and spray foam are two of them.

All insulation materials require proper venting. Get your kits the easy to use spray foam kit.