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.
Spray foam insulation or spray polyurethane foam (SPF) is an alternative to traditional building insulation such as fiberglass. A two-component mixture composed of isocyanate and polyol resin comes together at the tip of a gun, and forms an expanding foam that is sprayed onto roof tiles, concrete slabs, into wall cavities, or through holes drilled in into a cavity of a finished wall.
I started using Gaco years ago primarily to solve ponding water Problem. It has work well, solved my problems with other roofing options and repairs as well as many other Flat roof issues.  My only problems were experienced when I did not clean the surface well enough for good adhesion.  Follow the Instructions.  Great product and highly recommended. .
While coatings may potentially stop minor leaks, the roof should be properly repaired and dried prior to coating application. Coatings may be able to seal pinhole leaks, which are leaks not visible to the naked eye. If the roof is leaking, the roof leak will need to be identified and repaired prior to any recoating; do not expect the coating to find and seal the leaks.
Current guidelines recommend up to 10 inches of insulation in your attic . This is usually added to the ground, rather than the roof line, which results in the loss of your storage area, due to not being able to refit floor boards after installation. By implementing spray foam insulation to the roof line, you regain the lost 10 inches, thus increasing storage, height and practicality.

where to get spray foam insulation


Note: The practice of foam insulating the attic has raised eyebrows in the building industry because "standard" roofing techniques call for the attic to be ventilated; however, in a vented attic situation it will become approximately 130 degrees in the summer. There's no reason for an air-conditioning and vent-ductwork to have to work in that type of severe conditions. By applying Icynene right on the underside of the roof deck, the severe temperatures no longer exist in the attic. In short, the attic is now a "conditioned" space of the house that is just as comfortable as any other room in the home. This is called a "Compact Roof", which means you can frame right up against it. The one drawback of using expanded foam on the inside of the roof is that this will cause the temperature of the shingles to rise, but how much is not yet known. And how much damage a rise in temperatures could cause is debatable.
Spray foam is a fully adhered insulation that is spray applied into wall cavities, providing a continuous air and moisture barrier. Spray foam allows efficient use of your HVAC system and helps regulate the temperature fluctuations and humidity in your home. Spray foam effectively seals the building envelope, filling in any cracks and crevices, the common source of air and moisture infiltration as well as temperature variations.
Here's a simpler, less expensive alternative: Cut some 2-inch-thick rigid-foam insulation and glue it to the subfloor between the joists or support it with nails driven partway into the joists. Then fill any gaps between the edges of the foam boards and the joists using the canned spray foam sold at home centers or hardware stores. An even easier option is to nail the foam panels against the bottom edge of the joists and seal the joints with canned foam, but you'll lose some headroom and access to any pipes and wires between the joists. As with spray-foam kits, protect yourself and the floor from the dripping globs of canned foam. A full face shield, gloves, and a hat would be a good start.

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The process by which heat energy in the form of light (usually IR unless the substrate is hot enough to glow in the visible range) is emitted more strongly by warm surfaces and absorbed by other materials especially those of low IR reflectivity (think matte black finish). Radiant heat transfer does not require a medium. Foam insulation materials, such as spray foam insulation, are opaque to thermal radiation, like most solid materials.
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. http://www.youtube.com/e/ggLAUsiuI_o
Spray foam insulation or spray polyurethane foam (SPF) is an alternative to traditional building insulation such as fiberglass. A two-component mixture composed of isocyanate and polyol resin comes together at the tip of a gun, and forms an expanding foam that is sprayed onto roof tiles, concrete slabs, into wall cavities, or through holes drilled in into a cavity of a finished wall.
Solvent-based polyurethane coatings have excellent adhesion and when used as a base coat over asphalt, EPDM, TPO or PVC, it eliminates the need for a primer. The resulting savings on labor and material more than offsets the higher cost of the product. When top coated with silicone, it gives you the best of both worlds. It's also an excellent gutter and RV coating.

who sells spray foam insulation


Our roof coating sprayers are designed to provide the coverage, flow rate, and pressure needed for all your applications. Durable Graco roof coating sprayers are equipped with valuable features that make them extremely versatile. High-quality parts plus gas, electric, air driven, and hydraulic options means we’ll have a sprayer that fits your needs. Our systems are designed to be used with elastomeric roof coatings, silicone roof coatings, acrylic roof coatings, asphalts, rubber roof coatings, and other materials.

spray foam professionals


OK, Peter, I finally went back and read Alex Wilson's article on what he perceives as a serious problem. I haven't seen the full report, but based on the summary he wrote on the Green Building Advisor website, I question the science. It seems to me that he's chosen the wrong metric and he's basing his conclusion on too many assumptions because he doesn't have enough data. You can see my comments at the end of his article.

spray foam under house


Liquid Roof is a true EDPM rubber, and is the only one sold in liquid form. It makes installations easy. It can be described as a liquid version of the single-ply EPDM membrane that has established an outstanding performance record spanning more than 30 years. The EPDM chemistry has two unique features not possessed by any other rubber: It is unaffected by ultraviolet radiation and ozone and it can tolerate continuous exposure at temperatures above 300° F. The latter feature is also what gives EPDM rubbers the best aging properties of all elastomers (they retain flexibility longer).
While the R value will vary, most ocSPF products have an R value of around 3.8 per inch. Unlike medium-density closed-cell SPF, ocSPF is not a vapour barrier. When installed at 5.5 inches or more, ocSPF does act as an air barrier. It is often used for interior walls because it provides sound reduction by blocking and absorbing air leakage. It is usually only recommended for indoor applications.
Spray polyurethane foam, or SPF, is the main type of 2-part, closed-cell spray foam used by insulation contractors. Large-scale insulation jobs require special equipment as well as safety gear to protect the installer from chemical fumes during installation. When the foam cures and hardens just several minutes after application, it's completely safe for as long as it stays in place.

Our roof coating sprayers are designed to provide the coverage, flow rate, and pressure needed for all your applications. Durable Graco roof coating sprayers are equipped with valuable features that make them extremely versatile. High-quality parts plus gas, electric, air driven, and hydraulic options means we’ll have a sprayer that fits your needs. Our systems are designed to be used with elastomeric roof coatings, silicone roof coatings, acrylic roof coatings, asphalts, rubber roof coatings, and other materials.
Protect your lungs with a respirator, and be sure to wear a full protective suit, chemical-resistant gloves and wrap-around goggles. Tape your gloves to your sleeves and wear your junkiest shoes. Acetone will dissolve fresh foam right away, but once this stuff cures, it has to be physically scraped off. In general, if you don’t want it covered with foam spatter, keep it away from the action.
The video below is from a house near Charleston, South Carolina that I visited recently, and you'll see that the homeowner in this case didn't get his money's worth. I knew immediately when I walked into the attic that something was wrong because it was hot up there. In a properly insulated spray foam attic, the temperature won't be much higher than the house temperature. 

Johns Manville Corbond III® closed-cell spray polyurethane foam insulation offers and R-Value of R-7 per inch and can be applied in a single pass to a maximum of 3.5 inches, providing superior thermal performance with seamless air sealing and moisture control in a single step. Multiple immediate passes, with no wait time, may also be applied. With high yield and excellent adhesion, it's an ideal choice for high-performing energy efficient commercial, residential and industrial applications. https://youtube.com/watch?v=ggLAUsiuI_o
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