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.
Typical roof coating dry film thickness vary from paint film thickness (plus or minus 3 dry mils) to more than 40 dry mils. This means a roof coating actually becomes the top layer of a composite roof membrane and underlying system. As such, the roof coating is the topmost layer of protection for the membrane, receiving the impact of sunlight (both infrared and ultraviolet (UV), rain, hail and physical damage. https://youtube.com/watch?feature=player_embedded&v=ggLAUsiuI_o
There are two main types of spray foam to consider: open-cell and closed-cell. Open-cell spray foam has a lower R-value per inch and because of this, typically a lower price tag. The soft, low-density material is used for interior applications. Its high permeability allows for moisture to pass through, which contributes to bi-directional drying of the assembly, but it may not be ideal for all applications or climates. 
You've got no argument from me there, Dennis. Getting a good installer if you're going with spray foam is crucial. Many builders or homeowners don't know how to find one, however, and that's where third party inspections come in. Also, even good installers have bad days, but if someone comes in behind them with a measuring probe and a Blower Door, there will be fewer sub-par foam jobs.   

Before you decide on spray foam or another method of insulation, it's important to understand the superiority of spray foam compared to traditional materials. When compared to fiberglass batts, spray foam offers nearly double the R-value per inch, achieves air-sealing and insulation in one step, won't be damaged by mold or moisture, and won't settle, compress, or otherwise be damaged to the point it needs replacement.
I have been looking to have closed cell insulation added through out my attic space. I cant seam to find a installed that wants to install no more than 2 inches, and thats not near my R-valve for South Carolina (Lake Greenwood)please send any advice that will help me to see what installer will perform the correct job. This is a expense that i can only afford to do once. Sandi

Where Can I Purchase Spray Foam Insulation


We are turning our roof into an unvented roof assembly by raising the roof and blowing in SPF. We are planning to leave the existing vapor barrier down but remove the fiberglass batting and then adding 6" of SPF in all the cavities, to completely seal and insulate the house. Should we have any concerns about doing it "upside down" and not spraying the foam directly to the underside/sheathing of the roof?

If you’re looking for an effective and efficient Elastomeric Roof Coating, you might want to consider the Kool Seal roof coating. This product comes in a 115 fl oz container and is white in color. It is easy to apply and use that it can stick well even in the harshest weather conditions. This product offers maximum clinging to the RV roof despite the temperature. You can also rely on its effectiveness no matter the type of weather.
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.

How Much To Spray Foam Crawl Space


The average price to cover 200 square feet with a foam insulation kit will run between $300 and $600 (about two to three kits). Inside these kits is something called Icynene, a foam made from two liquids that are heated and pushed through a gun on the can. When Icynene is released, it expands up to 100 times its size as it hits the surface area you're covering. These can contain a lot of gasses, making its installation a dangerous process. Even low-pressure sprayers can be harmful to homeowners' health.
The problem was that the installer was doing his first spray foam job ever, and the thickness of the insulation varied from zero (visible roof deck) to about 9". Unfortunately, good average thickness doesn't cut it. The coverage needs to be uniform because a lot of heat will go through the under-insulated areas. (See my article on flat or lumpy insulation performance.)
R-value is the term given to thermal resistance to heat flow. The higher the R-value of an insulation product, the more effective the insulation properties. Spray polyurethane foam comes in a range of densities and cel structure. Low density foams are referred to as Open Cel SPF while higher density foams are referred to as Closed Cel foam. 1.8-2 pound polyurethane foam has the highest R-value of readily available spray foam insulation used in homes and buildings.[4]
I don't know if it's common or uncommon, but installing a layer of rigid foam above your roof sheathing in order to interrupt thermal bridging is always a good idea, and is preferable in all respects to a roof assembly without any rigid foam above the sheathing. If you decide to install rigid foam above the roof sheathing, you shouldn't use closed-cell spray foam under the sheathing; either use open-cell spray foam (which is vapor-permeable) or a fluffy insulation like cellulose, mineral wool, or fiberglass (any of which will allow the roof sheathing to dry to the interior). http://youtube.com/embed/ggLAUsiuI_o
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.
Allison--would be very interested in your take on the GHG issues of foams, which have received lots of smart commentary recently. To highlight a few: architect Jesse Thompson's comments on Tom's Good vs Bad post on Energy Circle, the very thorough piece by Alex Wilson on Green Building Advisor and Michael Anschel's cautionary diatribe on Remodeling. 
Spray Foam Insulation is simply the best insulation you can install in your home or building in Texas. It is estimated that up to 40% or more of your home's energy loss is due to air leakage through holes, cracks and gaps in the building structure. SPF can seal your home from air and moisture leakage, save on costly utility bills, strengthen your home, and help to protect your family's health from dangerous mold and airborne pollutants. https://www.youtube.com/watch?feature=player_embedded&v=ggLAUsiuI_o
Air infiltration and exfiltration within a home contributes to almost 99% of moisture migration. Restricting air movement stops moisture accumulation so that the possibility of mold growth is less likely. Combined with a properly sized HVAC system, spray foam insulation helps control the indoor humidity levels to minimize moisture and condensation. Reducing moisture and controlling humidity can also add years to the life expectancy of a home, plus contribute to a healthier indoor environment. Finally, it also deters pests, making it difficult for them to nest.

How Much Is Spray Foam Insulation Per Square Foot


Heat which is created elsewhere that is transported by means of a fluid, such as water or in our case air. Spray foam insulation's most important attribute is the ability to air seal creating a custom airtight envelope within the building structure. The added benefit to air sealing is the ability to block convective heat transfer from interior to exterior during heating months and vice versa during cooling months, as the heat cannot escape through gaps in the buildings envelope without the aid of air movement from infiltration as a means of transport.
It also has a great waterproofing ability that can shield the roof’s membrane from water and moisture damage. You can also count on the liquid roof coating for its outstanding performance for a wide range of applications and uses. This product can be used at tears and seams as well as in sealing air conditioners and venting systems and anywhere else where rubberized coating is needed. https://m.youtu.be/ggLAUsiuI_o
The average price to cover 200 square feet with a foam insulation kit will run between $300 and $600 (about two to three kits). Inside these kits is something called Icynene, a foam made from two liquids that are heated and pushed through a gun on the can. When Icynene is released, it expands up to 100 times its size as it hits the surface area you're covering. These can contain a lot of gasses, making its installation a dangerous process. Even low-pressure sprayers can be harmful to homeowners' health.

How Much Is Spray Foam Insulation

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