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).
Clean and free the roof surface of any debris and then dry the surface using a cloth. If you happen to have a current coating on the surface, check for adhesion. Consider removing loose coating, repairing, cleaning and then checking the area. Remember to use Energy Guard without thinning it because it is sold ready for use. Containers should not be left open except for a short period of time. You must also ensure that you check for any existing coating adhesion before opening Energy Guard. For application, you will require a brush preferably a bristle brush (synthetic) or a short nap roller. You can also use a good airless sprayer with a 0.031 or 0.027 tip to apply the coatings at (3000 psi/1gpm). You will also need water for cleaning up when you are done.
Light-density open-cell SPF is commonly known as half-pound foam. It is a semi-rigid material with a sponge-like appearance that expands during installation and creates small, open cells that are filled with carbon dioxide. Due to its ability to expand during the application process, it fills cracks, crevices and voids and adheres to irregular surfaces or substrates to form an air sealing insulation.[12]
Henry 587 Dura-Brite White Elastomeric Roof Coating is Henry 587 Dura-Brite White Elastomeric Roof Coating is a premium high solids formula offering better weather protection solar reflectivity and longevity than economy grade reflective roof coatings. Cured coating forms a permeable membrane which prevents liquid infiltration but allows moisture vapor to vent or breathe out of underlying substrate. Recommended ...  More + Product Details Close
Light-density open-cell SPF is commonly known as half-pound foam. It is a semi-rigid material with a sponge-like appearance that expands during installation and creates small, open cells that are filled with carbon dioxide. Due to its ability to expand during the application process, it fills cracks, crevices and voids and adheres to irregular surfaces or substrates to form an air sealing insulation.[12]
If you cut the nails holding one of the corner studs to the bottom plate and the top plate with a Sawzall, you can use a flat bar (or a flat bar plus a wrecking bar) to pull the stud off the sheathing nails. Either re-use the stud, or buy a new stud, and install the stud with toenails as shown in the link I provided in Comment #51 (this link: Outside corner detail). http://m.youtu.be/ggLAUsiuI_o
Touch ‘n Foam Pro System 600 is a completely self-contained 2-component foam system that is portable and disposable. Complete with color-coded hoses, ergonomic foam applicator, and all the necessary tools to get started, the System 600 provides up to 600 board feet* (theoretical) of polyurethane spray foam. Designed for larger insulating (up to 2 inch fills), sealing, patching and filling applications, the System 600 provides a quick, consistent flow of foam with rapid curing (60 seconds) to insulate stud wall cavities, gaps, cracks, expansion joints, and other sources of air leakage.
Note:  A board foot is defined as a 12" x 12" square at 1" thick. Actual output can be affected by a number of factors including temperature and humidity. The theoretical yield has become an industry standard for identifying certain sizes of two component kits. Theoretical yield calculations are performed in perfect laboratory conditions, without taking into account the loss of blowing agent or the variations in application methods and types. 

If you haven’t considered spray foam insulation, now may be the time to start looking into it. As you know, having proper insulation will help reduce your heat and air conditioning bills. In specific, spray foam insulation can be particularly helpful during renovations. It can provide a barrier between outside walls, and even a sound barrier for the inside.
For maximum durability and leak resistance, we recommend that two coats of topcoat be applied at 100 sq. ft. per gallon, or a minimum of 20 mils dry coating. If two complete topcoats are not applied, always apply two thick coats to problem areas such as scuppers, drain areas, ponding areas, seams, and repaired areas. Avoid using Elastek Solar Magic™ or The Shield™ on ponding roofs. Clean skin and tools promptly with water.
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.
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. https://youtube.com/v/ggLAUsiuI_o?version=3
Thank you, Allison. We have a split system unit (actually 5) with the heat being propane. The foam guy said that it needed ventilation, so completely sealing the attic wouldn't be a good idea. It sounds like you are saying that the systems need to be vented out of the attic or replaced with some type of closed system. But I shouldn't bother spraying if the plan is to leave the soffet vents open. Is that correct? https://www.youtube.com/v/ggLAUsiuI_o&feature=kp

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 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.

RE: my June 12 post...We went ahead and had the attic sprayed with a Soy-based product. Stayed in a hotel for 3 nites. Still smelled a little bad but that's gone away over time. I'm very glad we didn't use the other foam as even that much outgassing of a petrochemical could have sent my wife to the hospital. Unfortunately, the spray crew didn't speak English(at least not to me) and were kinda lazy, so they ended up spraying over some can fixtures from the kitchen below that were not insulation-contact rated. So I hired an electrician to come out, pull down the cans, pull out what he thought was an appropriate amount of foam to create a big enough air space and then re-install the cans. I billed the firm for the electrician plus an extra night we had to stay in the hotel and they paid, no questions asked. Guess they knew they had screwed up.  


Although spray polyurethane foam has many advantages over other types of insulation, spray foam installation isn’t foolproof. Some builders have reported problems with sloppy foam insulation. For example, some installers have been known to begin spraying before the chemical components are up to temperature, which can affect component mixing and foam performance. When components are poorly mixed, or mixed in the wrong ratio or at the wrong temperature, cured foam has been known to shrink away from rafters or studs, leaving cracks. Some installers rush through their spraying, resulting in voids.
Acrylic coatings are typically applied in two coats, with the second running perpendicular to the first. 1 gallon per 100 square feet is a good estimate for these coatings, as they do not need to be applied nearly as thick as many other coatings. These coatings can be sprayed or roll-applied. Acrylic coatings generally require a re-coat within 2-3 years of application.
Elastomeric coatings offer effective and affordable solutions for fixing roof leaks. The coatings can be used to repair any type of roof leak. The elastomeric roof coatings can be used throughout the year because they stretch and contract easily to adjust to winter and summer temperatures. It is usually made using polymeric products such as acrylic alongside white pigments like titanium dioxide. This helps create an opaque and reflexive final product.

What do you mean by "our AC units require fresh air ventilation"? Fresh air doesn't come from the attic. If there's an atmospheric combustion appliance in the attic, such as an 80 AFUE furnace, then you shouldn't be encapsulating the attic anyway. If that's the case, you don't want spray foam on the roofline at all. You can either change out the furnace to a sealed combustion unit or do your insulating and air-sealing at the flat-ceiling level. https://www.youtube.com/v/ggLAUsiuI_o&feature=share


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.  
Spray foam is available in two different types: open-cell spray foam which is usually $0.44 to $0.65 per board foot and closed-cell spray foam which is about $1 to $1.50 per board foot. The average cost to have spray foam professionally installed is about $2,314. This number can vary depending on whether the home being insulated is newly constructed. However, finished homes are not a good candidate for spray foam insulation but great for weatherization or an energy audit.  
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.

How Much Does Spray Foam

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