Spray Foam Insulation On Roof Rafters

The spray foam can also serve as the thermal and vapor control layers in both new and retrofit construction.

Spray foam insulation on roof rafters.

R value of 7 in 1 inch 97 closed cell foam. The best attic insulation. 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. 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.

Use closed cell foam it green for attic rafters. Get your kits the easy to use spray foam kit. Spray foam insulation that s convenient and easy to use. Because spray foam insulation applied to the underside of roof sheathing inhibits heat conduction.

In an uninsulated attic the heat passes through roof sheathing and disperses into the attic space. 100 free of cfcs vocs penta bdes urea formaldehyde. Lstiburek takes blame for bad language. Heat from the house rises up to the attic but when there isn t one the heat rises up to the roof.

Class i e 84 fire retardant meets building code spec. It s not coming from above the roof and it s not some new moisture source resulting from the spray foam. All insulation materials require proper venting. 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.

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. Cathedral roofs especially need a lot more insulation between the ceiling and the rafters because there usually isn t any attic space.