In a single application, Heatlok Soy 200 Plus can create a specialized engineered building envelope, which provides better thermal resistance, excellent air barrier, and a recognized vapor retarder. Demilec continues to strive toward innovative, scientific advancements in high-efficiency spray foam insulation solutions, intumescent and elastomeric coatings, high-performance quality products, and superior service.
Polyurethane is a closed-cell foam insulation material that initially contains a low-conductivity gas in its cells. As a result of the high thermal resistance of the gas, spray polyurethane insulation typically has an initial R-value around R-3.4 to R-6.7 per inch. In comparison, blown fiberglass typically has an R-Value of only R-3 to R-4 per inch.
A. You can use closed-cell spray foam that way if you want, although you should realize that the spray foam will prevent the roof sheathing from drying inward. This approach should only be used if the roof sheathing is bone dry, because it will never dry when sandwiched in this manner. Most building scientists would prefer to see fiberglass rather than closed-cell spray foam under the roof sheathing in this type of assembly.
Never spray foam on a surface with a moisture level of more than 20 percent—the foam won’t stick. If the surface you’re spraying hasn’t been exposed to water for a few weeks, it should be OK to spray. But if you’re patching a wall that recently sustained water damage, or was just assembled with new, wet lumber, you may want to test the moisture level before you spray. You can get a moisture meter here.
You probably have some familiarity with spray foam insulation, and you may have even used the foam that comes in pressured spray cans at home improvement retailers. This foam is know as one-part foam, meaning that it is one continuous mixture that is simply applied to the area in need. One-part foam is frequently used for sealing small gaps and cracks. http://youtube.com/watch?v=ggLAUsiuI_o