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.

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.
As this example illustrates, it's important to seal the envelope completely. One of spray foam's biggest selling points is its air-sealing ability, but it can't seal places where it's not sprayed. One of the nice things about using spray foam in new construction is that you can do a Blower Door test before the drywall goes in. Even better, you can test for leaks with a fog machine.
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.
JM Corbond® Open-Cell Appendix X Spray Foam is a lower-density, nonstructural foam that offers most of the thermal performance and installation benefits of closed-cell spray foam at a lower cost. It provides an exceptional air and sound barrier as well as R-value, and meets AC 377 NFPA 286 Appendix X requirements for application without an ignition barrier in attics and crawl spaces.

This is more common with closed cell foam, but it happens with open cell foam, too. Since closed cell foam has a higher R-value per inch, installers generally spray 2" in walls and 3" in rooflines to meet the energy code requirements of R-13 and R-19, respectively. (I'm not going to dive into the energy code here, but these numbers apply to many climate zones, the latter being allowed under the UA tradeoffs rule. See the Energy Nerd's blog on this topic if you want to argue.)
During colder months, 2 component foam is very sensitive to temperature variances. Per product instructions, both tank temperatures need to be above 70°F (21°C) for at least 24 hours prior to use. All application surfaces should be clean/dry and above 60°F (16°C) prior to application. Variance outside of the recommended temperature can affect foam yield and performance. https://youtube.com/v/ggLAUsiuI_o?version=3

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.


When choosing a waterproofing and sealing product, we must see to it that we can easily use and apply it using simple tools, including a squeegee or a paint roller. With ease of application, we can be certain that we can achieve hassle-free application and smoother and more attractive finish than other products could give. So when reviewing the products we have featured above, we have made sure that they are easy to apply.
a) Make sure that your house has been well heated prior to installation because the foam expands at different rates as it hits surfaces with different temperatures. If it is cold outside the sheathing may be much colder than the studs consequently the foam may expand more from the sides of the wall cavity creating air pockets in the wall cavity. This can be minimized by an experienced installer.

Spray Foam Tanks


Determining which type of SPF is right for the project involves evaluating the application area, overall budget, and scope of a project. Review insulation needs in attics, walls, ceilings, and other areas, and account for factors like project location, climate and how the building will be used. For example, an indoor swimming pool will drive towards a different SPF selection than an office building. 
I employed a company to insulate my three story house in 2011. They started Insulating it in August of 2011...They said it would be a 3-4 day job. They installed it in 0.5"-8" lifts all in the same cavity, this left burned insulation and voids. They removed what they told me was the bad insulation and in the process cut many electrical wires. They fixed this. They then reinstalled too thick again in some spots and removed again. They then installed it for a 3rd time. The areas that I thought were good are now separating from the structural members leaving voids. As of October 2012, 1 year and 2 months of dealing with the contractor I told them I want proof that what has been installed carries a warranty or I want my money back and I will fix the problems myself. They have yet to provide me with this warranty. I have spent many hours in the house looking at what is bad and they need to fix. I am frustrated, 14 months of additional rent due to their negligence. I would like to know how I can get proof that the product carries the manufacturers lifetime warranty, or has it been installed improperly throughout the entire house. Desperately awaiting your response. 
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.

Roof Coating Seal

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