Open Cell Spray Foam Attic

Light density open cell spray foam insulation and medium density closed cell spray foam insulation.

Open cell spray foam attic.

Some spray foam manufactures have tested primer coating products that result in the formulation of a class ii vapor retarder directly on the surface of the open cell spray foam. The superior air sealing performance of spray foam insulation both open and closed cell results in moisture movement by vapor diffusion increasing in importance. It has a relatively high vapor permeance 3 perms allowing water vapor to migrate to the roof decking at night and back into the attic air in the daytime. It s just a pathway.

Open cell spray foam can also be used to create an unvented attic in cold climate zones provided code requirements for a vapor retarder are followed. Open and closed cell foam insulation use a blowing agent to forms the cells within it. Closed cell foams use enovate also known as 245fa. This makes the foam a softer more flexable material.

It rots roofs people have told me. The spray foam insulation or spray polyurethane foam spf is a popular alternative to traditional building insulation such as fiberglass. This spray foam is applied as a low or high pressure two component polyurethane spray foam that can be applied onto walls in unvented attics to ducts and ceilings and in vented attics and. Open cell foam weighs 1 2 pound per cubic foot and closed cell weighs 2 lbs per cubic foot.

An open cell foam low density spray polyurethane is a spray applied to provide continuous insulation and an air sealing barrier. Open cell spray foam insulation doesn t store the moisture. Open cell foams use water as a blowing agent. There is 300 difference there but the cost they give you is about a third difference and open cell foam at 12 inches will not give you the performance of 2 inches of closed.

Murmurs and hearsay about open cell spray foam insulation have been gaining traction for a while. Open cell foam is full of cells that aren t completely encapsulated. This type of spray polyurethane foam can be classified into two different types. The myth that open cell is more economical is bullshit.

Building code vapor retarder requirements for unvented attic construction have been in place since the 2009 irc and have resulted in thousands of successful assemblies that contain. Not long ago someone even told me that in florida roofing companies won t let their workers go up on roofs with open cell spray foam because the roofs are so spongy the guys fall right through. The role of open cell spray foam.