1 2 Pound Foam Unvented Roof

In the most recent issue of fine homebuilding martin holladay wrote a piece on insulating unvented roof assemblies.

1 2 pound foam unvented roof.

Ccspf or closed cell medium density spray foam 2 pound or 2 pounds per cubic foot and ocspf or open cell low density spray foam half pound or 0 5 pcf. With three layers of 11 2 in. Deck for a thick roof rigid foam insulation installed above the roof assembly can create an energy smart roof. Your comment still stands though there should only be 1 airtight seal.

Of cellulose insulation in the rafter cavities the roof shown here has an r value of approximately 63. All of these materials are supported by quality assurance testing capabilities that. We re big fans of fine homebuilding. Polyisocyanurate insulation above the sheathing and approximately 91 4 in.

The project in question is a new single family dwelling. However i d need to have an airtight seal for the vb to be superfluous. There are currently two types of spray polyurethane foam spf insulation used in north american residential construction. 1 spray foam insulation applied to attic roof.

We agree that avoiding sheathing rot is critical and that air permeable insulation such as fiberglass or cellulose cannot be used alone. Just have a contractor install spray foam insulation and you will be much happier with an efficient insulation that actually works and controls moisture. Since i m attaching the foam to whatever siding is there i haven t ripped out the old insulation yet to take a look i don t know if i ll be able to create an airtight seal. 5 1 2 inches can be filled or almost filled with 1 2 pound open cell foam or you can go with 3 to 4 inches of 2 pound closed cell foam.

1 pound spray foam insulation applied in attic. If you don t want to use sips or nailbase read this article tolearn the four basic approaches to insulating unvented roof assemblies. Ocspf is 1 2 pound per cubic foot open cell spray polyurethane foam ccspf is 2 pound per cubic foot closed cell polyurethane foam. Unvented attics insulated with spray foam duration.

Unvented roof space article 9 19 1 1. It was further assumed that a large enough rafter space was. A roof deck over habitable space is proposed to be insulated with two pound spray foam applied between the joists with no venting between the insulation and the underside of the sheathing. We have the capabilities to spray and inject a variety of foam systems to achieve a high r value while providing both effective vapor and air barriers.

Foam free don t stay stuck in the sci finightmare of foam foam foam. Unvented roof assemblies are outlined in the. The roof rafter space was assumed to be filled with sufficient insulation to meet the 2009 irc code values based the doe zone listed in table 1.