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. https://youtube.com/embed/ggLAUsiuI_o
Low-density foam is applied as low or high-pressure, two-component polyurethane spray foam. Low-density spray foam can be applied on walls, in unvented attics, to ducts and ceilings, and in vented attics and crawl spaces. It is known as an air barrier, but permeable to vapor and moisture. It is often used to fill cavities in walls during construction. https://www.youtube.com/e/ggLAUsiuI_o
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.
In the early days of insulating attics, people believed the insulation was a heat source. That’s not the case, as the insulation is actually a barrier between two areas of different temperatures. As for the “hot roof” theory, the unvented attic system could make the temperature of the roof go up a little, but this increase won’t cause damage to your shingles.
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? 

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I don't even want to ask this question but... several years ago we hired a local contractor to spray high density foam on the roof deck and walls of our unfinished 2nd floor. We realized that the job was done poorly and cut an access into the attic space to assess things. We realize now that they spray foamed directly to the chimney (no flashing). The chimney is currently used for a woodstove and DHW venting. The DHW will go away but wood stove will remain. My question is, how bad (unsafe) is this? I have found information on foam exposure to fire but have not been able to find anything about temperature ratings in general (i.e. what happens on prolonged exposure to high temperatures).

Spray Foam Roofing


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. 

How Much Does Spray Foam Insulation Cost


In addition, it's difficult for an inexperienced installer to evenly spread the insulation foam over a surface. Miissing spots can leave holes and gaps for cold air to get through. Proceed with this project yourself only if you're doing a small insulation project -- such as installing foam in a crawl space or around your plumbing. Leave larger projects like the attic, basement or garage to the professional insulation contractors. Insulation professionals have the tools, equipment and background knowledge necessary. Moreover, they know how to accurately price insulation, whereas you could inaccurately budget for a DIY project and end up paying significantly more. Don't take the medical, physical or financial risks that come with pursuing this as a DIY project unless you're absolutely certain you have the skills.
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.)

One of the high-tech insulation products being utilized these days is a foam-spray product called "Icynene," which is a foam that starts as two liquid components (a and b, if you will) that are heated up and sent through two hoses and meet at a tip of a gun where the magic begins. This is a thin film that expands to 100 times its volume in eight seconds, when it's permanently set up.
Closed-cell foam has a higher density and offers a higher R-value per inch. It also adds strength to walls, ceilings and roofs and can contribute to a structure’s overall durability. Additionally, closed-cell foam’s low water vapor permeability offers protection from moisture when installed in places where high humidity—from climate, occupants, or flooding—meets the structure. 
The guys who sprayed my attic were trained and certified, but I later found out, too late, that they had no experience and my attic was the first they'd ever sprayed. I was also never told to vacate my house for any length of time, and so I (and my pets) were in the house the day they sprayed and the entire time the off ratio foam was filling my home with horrendous vapors. The company kept telling me that it was a good job and I had nothing to worry about, even after I'd had 2 other experienced sprayers from 2 different companies visually examine the foam and confirm that large areas appeared to be off ratio. The 3rd sprayer from yet another company, was also outraged because the company who did my attic had failed to vacuum up all of the old cellulose insulation, and he also noticed areas where the foam was shrinking or pulling away, and this was not even 5 weeks after the spraying.  
Spray foam insulation works by sealing the building envelope to stop conditioned air from escaping and prevent unwanted outside air from entering your home. It allows efficient use of your HVAC system and helps regulate the temperature fluctuations and humidity in your home. It's a lightweight, durable, and versatile insulation solution boasting the industry’s strongest performance in energy efficiency and energy cost savings.
These coatings contain various types of acrylic polymer, and are typically formulated to help extend the coating’s life and improve durability. Acrylic coatings are available in a number of colors but are most commonly used as white reflective coatings. Thanks to its durability and low cost, many contractors and facility managers believe this to be the best roof coating.
According to the Department of Energy, an estimated 20 to 40 percent of a home’s utility bill could be going to waste from drafts and air leaks around openings. As temperatures cool and energy costs rise, the positive impact of energy efficiency on a building comes into focus. Air can enter and escape a structure through every gap, compromising the building envelope. Adding the right insulation and air-sealing will close these gaps, keeping interior spaces comfortable and reducing energy bills. 
The insulation at eaves level will leave your loft area comfortable for use and free from condensation. By installing the insulation at rafter level, it keeps the loft void warmer and prevents condensation build-up, which can otherwise occur when increasing insulation at ceiling level. The warmer, drier, cleaner roof space eliminates the risk of pipes and tanks freezing.
We carry a full line-up of the best roof coatings and roof waterproofing products - all tested in extreme climates. Our lines include both high-performance and cost-effective solutions. RoofMate HT is a high performance Elastomeric Roof Sealant for light traffic areas. Lucas 6000 universal is a superior high performance top coating. SilverWhite aluminized metal roof coating for metal roofs helps prevent rust. Roof Mate from United Coating has formulas for all type of roofs and  warranties available for up to 15 years. NovaTuff 2-part flexible epoxy systems are top-of-the-line waterproofing grade roof coatings with extremen chemical and salt resistance. For a cost effective quality foam roof recoat, we recommend UltraShield acrylic elastomeric roof coating. UltraShield is available in popular earth-tone colors and in 55G drums.
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. http://www.youtube.com/watch?v=ggLAUsiuI_o

In the early days of insulating attics, people believed the insulation was a heat source. That’s not the case, as the insulation is actually a barrier between two areas of different temperatures. As for the “hot roof” theory, the unvented attic system could make the temperature of the roof go up a little, but this increase won’t cause damage to your shingles.
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
Jennifer, I'm not an expert on the health effects of closed cell foam. A lot of people live in houses with closed cell foam and have no health problems from it, at least not short-term, acute problems. I do know of one person who had it removed from her crawl space because she was convinced it caused her dog to get sick, but I know only what she told me.  
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 .
Most flat roofs are not perfectly sloped, causing water to puddle in some areas, in particular around the drains and scuppers. Many roof coatings are not rated or warranted for "ponding water", and thus might fail pre-maturely if exposed to standing water over long periods of time. Serious consideration should be given to the performance and limitations of the coating being selected. Some manufacturers will warranty their coatings including ponding water. Typically, manufacturers for acrylic roof coatings do not include warranties for ponding water, while some polyurethane and silicone roof coatings manufacturers will. https://youtube.com/watch?feature=youtube_gdata&v=ggLAUsiuI_o
Carefully examine the roof membrane (surface material) for cracks, tears, blisters, evidence of ponding, exposed foam, and open seams. If already coated, evaluate the condition of the coating. Pay particular attention to areas around roof penetrations (vents, skylights, pipes, etc), ponding areas, cracks in parapet walls, and the attachment of roof membranes to parapet walls. Roofs should be in good condition to warrant coating.
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.
Demilec, a company located in Texas, has invented a type of insulation foam that can help all of the cracks and uneven pavement problems. Geolift can help to lift existing concrete surfaces and fix those problem areas around your house with much less labor. Geolift works for driveways, sidewalks, patios, garage floors, even pool decks. And yes, it is a foam, just like your beloved spray foam! http://youtube.com/watch?v=ggLAUsiuI_o
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. 
According to the Department of Energy, an estimated 20 to 40 percent of a home’s utility bill could be going to waste from drafts and air leaks around openings. As temperatures cool and energy costs rise, the positive impact of energy efficiency on a building comes into focus. Air can enter and escape a structure through every gap, compromising the building envelope. Adding the right insulation and air-sealing will close these gaps, keeping interior spaces comfortable and reducing energy bills. 

Spray Foam Walls


Loctite TITE FOAM Window and Door is a Loctite TITE FOAM Window and Door is a new generation of polyurethane-based insulating foam sealant that expands to fill seal and insulate around window and door jambs. Loctite TITE FOAM is a minimal-expanding foam based on purified and concentrated ingredients that provides four times more density versus conventional window and ...  More + Product Details Close

How Much Is Spray Foam Insulation A Square Foot

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