1 2 Pound Foam Unvented Roof

With three layers of 11 2 in.

1 2 pound foam unvented roof.

Of cellulose insulation in the rafter cavities the roof shown here has an r value of approximately 63. Polyisocyanurate insulation above the sheathing and approximately 91 4 in. 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. We re big fans of fine homebuilding.

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. 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. Unvented roof assemblies are outlined in the. 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.

Unvented roof assemblies should be insulated either with air impermeable insulation rigid foam or spray polyurethane foam or with a combination of foam and air permeable insulation. We agree that avoiding sheathing rot is critical and that air permeable insulation such as fiberglass or cellulose cannot be used alone. All of these materials are supported by quality assurance testing capabilities that. Unvented attics insulated with spray foam duration.

Unvented roof space article 9 19 1 1. 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. Deck for a thick roof rigid foam insulation installed above the roof assembly can create an energy smart roof.

Insulating unvented roof assemblies. It was further assumed that a large enough rafter space was. The project in question is a new single family dwelling. In the most recent issue of fine homebuilding martin holladay wrote a piece on insulating unvented roof assemblies.

1 pound spray foam insulation applied in attic. Just have a contractor install spray foam insulation and you will be much happier with an efficient insulation that actually works and controls moisture. Foam tech creates superior insulation and environmental control solutions by installing safe cost effective and environmentally friendly polyurethane foams. If you don t want to use sips or nailbase read this article tolearn the four basic approaches to insulating unvented roof assemblies.

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. Your comment still stands though there should only be 1 airtight seal. 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.