“It’s been scientifically proven that the temp of the shingles rises only a couple of degrees when there is an unvented attic compared to a vented attic,” said Garry Barlow, estimator at RetroFoam of Michigan. “If we lived in a southern state it has been proven that the longevity of the shingle did diminish by only one year. In the northern states there was no difference in the life span of the shingles.”
I've seen this only once, and it was with closed cell foam, but I've heard of it happening with open cell foam, too. I don't know the details, but I've heard it could result from a bad batch of chemicals, improper mixing, or too high a temperature. Whatever the cause, it's not a good thing. The photo below shows how the spray foam pulled away from the studs. A little bit of uninsulated area like that adds up to a lot of heat loss/gain when the whole house has that problem, as it did here.
R-value, the thermal resistance measure of insulation, varies between all insulation products whether they are fiberglass, cellulose, open-cell spray foam insulation or closed-cell sprayed-in foam insulation. Generally speaking the rule of thumb is the higher the R-value, the greater the insulating power. Focusing on spray foam insulation materials, there is a difference between the two main types. According to industry publication, Fine Home Building, the R-value for open-cell spray foam is between R-3.5 – R-3.6 per inch. However, there are open-cell spray foam insulation products actually offer R-3.7 per inch such as Icynene Classic and Icynene Classic Max. The open cell structure of low density foam insulation means the R-value is lower than its closed-cell counterpart. Nevertheless, open-cell spray foam does offer superior and consistent thermal insulation and air sealing properties.
Where Can You Buy Spray Foam Insulation
For large jobs, professionals such as Dr. Energy Saver use two-part foam, which comes in larger containers. With 2-part spray foam, it's necessary to mix separate resin and catalyst compounds at the application nozzle. Combining these ingredients starts a chemical reaction that creates expanding foam. Contractors use small 2-part foam "kits" to air-seal an attic or to seal and insulate ductwork. To insulate an entire attic or wood-framed wall with spray foam, the resin and catalyst compounds are pumped to the application nozzle from 50-gallon drums in a specially equipped truck. http://kvsprayfoam.com/images/spray-foam-insulation-.jpg
c) Make sure that the over expanded access is properly removed from the walls. We had a junior cutter taking too much off by bending his saw into the cavity. Look closely at the inside wall corners, and ceiling/wall corners to make sure that the foam is properly removed flush with the studs. If it has not been cut back flush it may lead to uneven drywall finishes .
I live in Baton Rouge LA with a very old and drafty house. There is no blockages in the walls between the crawl space and attic. Lots of critters just come on in. I would like to used closed cell sprayed under house to warm up floors and block moisture. I would like to spray closed cell into attic, but am afraid of enclosing attic due to moisture build-up. Can I spray closed cell against the attic floor in same way as installing bats, thus leaving my venting the same as it always has been. Other ideas? Thanks.
Ames® Roof Coatings are premium elastomeric coatings that seal out moisture, renew old surfaces and even save energy. We have products specifically formulated for all types of roofs including; Wood, Tar, Metal, Rolled Roofing, EPDM Rubber, Foam and many other surfaces. Ames’ coatings form a waterproof seal to preserve and protect your roof. Our white roof coatings reflect sunlight, substantially reducing roof temperatures. Ames® products are environmentally friendly, waterbase, non-toxic, VOC-free and water cleanup.
Check with the coating manufacturer who may be able to suggest applicators who have used their products and have familiarity with the application. Another option would be to interview contractors and ask specific questions about their proven ability to install roof coatings. Contractors affiliated with the National Roofing Contractors Association (NRCA) or local roofing contractor trade associations typically are more knowledgeable. Consult those groups’ websites for contractors.