Open Cell Vs Closed Cell Spray Foam Roof Humid Climate

So what is it with the family food fight.

Open cell vs closed cell spray foam roof humid climate.

Kit 60 sf coverage. Quick cure best seller kit 605 sf coverage best seller kit 205 sf coverage. The cells are pressed together so air and mositure are unable to get inside the foam. Spray polyurethane foam spf can do stuff that no other stuff can do.

For example closed cell foam is really the only option for residential roofing adhesive due to its strength characteristics. On the interior side of any open cell spray foam installed on the underside of roof sheathing. 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. Folks i have got news for you regarding the open cell closed cell thing.

It rots roofs people have told me. Most open cell foam has. In addition to the situation specific considerations there are more general considerations to make when deciding between open cell and closed cell foam. The microscopic cells within open cell foam are just that open which give it a soft fluffy feeling.

Low density open cell is better than high density closed cell or is it vice versa. Kit 340 sf coverage. Open cell spray foam insulation doesn t store the moisture. Closed cell foam is much denser than open cell foam.

Closed cell foam is made up of cells that are as the name suggests completely closed. 280dc uv protecting paint for foam. It has a relatively high vapor permeance 3 perms at a thickness of 6 allowing water vapor to migrate to the roof decking at night and back into the attic air in the daytime. Kit 205 sf coverage.

Because of this closed cell foam is much more rigid and stable than open cell foam. It s the wood decking that stores the moisture though. It s just a pathway. There is no wrong answer.

Kit 105 sf coverage. Murmurs and hearsay about open cell spray foam insulation have been gaining traction for a while. Because the open cell structure allows some vapor to pass through open cell foam is a good choice in hot humid climates and under roof sheathing such as in conditioned attics where water vapor caught between insulation and sheathing could promote wood rot. Since vapor retarder paint wont work unless drywall is first installed on the interior side of the closed cell spray foam and since installing drywall is expensive most cold climate builders avoid the use of open cell spray foam in attics.

Closed cell spray foam on the other hand is also called medium density or 2 0 lb foam.