We have a 1950's ranch in Atlanta and are interviewing foam contractors to spray open cell under the roof, with an "ankle wall" out towards the eaves to seal the attic. My wife and daughters are chemically sensitive, so I'm trying to figure out how to minimize the fumes coming into the house. Additionally, at least one contractor has offered (for > $900) to remove our existing rock wool & R-13 fibreglass from the attic floor to "increase cross-ventilation into the attic". Seems to me I can't both minimize fumes AND increase cross-ventilation. They also offered to spray a fire-retardant on for >$600. Would ventilation during installation help any or woud the retardant seal off the foam and help that way? Thanks... 

Spray Foam Insulation


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.
This high R-value of 4.45 at 1 inch, polyurethane insulation expands to seal cracks, gaps, and voids in attics, walls, crawl spaces, and ceilings. Agribalance is a three-quarter pound density foam that reduces air leakage by improving energy efficiency, and reducing moisture intrusion and outside contaminants such as dust, dirt, and allergens. As a result, builders can generally install smaller, more energy-efficient HVAC systems and achieve similar, or superior comfort compared to traditionally insulated structures which require a larger, less efficient HVAC system – resulting in higher energy costs.
If your foam pulled away just a little bit, Jamie, and they were able to fix it with just a little bit of touching up, then it wasn't as bad as the house where I saw this problem. As the last photo above shows, it had pulled away significantly from the studs and rafters, and it was all over the house. This was closed cell foam, and interestingly, it didn't pull away from the horizontal framing members, just the vertical and sloped ones. They did some touch up, but that wasn't enough. I don't know how this one ended up getting resolved. I think maybe the contractor came back and sprayed cellulose on top of the foam.

How Much Is Spray Foam Insulation A Square Foot


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
Roof Coatings should not be confused with deck coatings. Deck coatings are traffic bearing - designed for waterproofing areas where pedestrian (and in some cases vehicular) traffic is expected. Roof coatings will only waterproof the substrates but will not withstand any kind of on going use by people or vehicles (such as walkways, patios, sundecks, restaurants, etc.). http://youtube.com/v/ggLAUsiuI_o?version=3

Sean, thanks for jumping in and answering John's questions. About choosing the right foam, I intentionally avoided the open cell vs. closed cell foam debate. I did this partly because it's worthy of an article all by itself, but mainly I didn't include it because, despite all the warnings the two sides issue about the other, I've never personally seen a problem caused by using open cell where they should've used closed cell or vice versa. I'm sure things like that happen; I just haven't seen it yet.
Roof Coatings should not be confused with deck coatings. Deck coatings are traffic bearing - designed for waterproofing areas where pedestrian (and in some cases vehicular) traffic is expected. Roof coatings will only waterproof the substrates but will not withstand any kind of on going use by people or vehicles (such as walkways, patios, sundecks, restaurants, etc.). http://youtube.com/v/ggLAUsiuI_o?version=3
Open-cell is also known as half-pound foam. It has an R-Value of 3.5-3.6 per inch, and its density is bout 0.5 pounds per cubic food. Low-density foams like these are made partially from raw biological materials Carbon dioxide or water is also used in the makeup. Open-cell uses far less material than closed-cell, but its R-Value is lower. Also, open cell requires a vapor retarder (like gypsum wallboard) and is riskier when used for roof sheathing. It's not highly recommended that you use open-cell insulation if you live in a cold climate unless you have that extra barrier. You should also compare how much money you spend versus how effective the open-cell insulation is wherever it's installed.
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. http://youtube.com/e/ggLAUsiuI_o?app=desktop
Steve: If your spray foam installer leaves the vents open, he will be committing the 2nd of the 4 problems I described above. You will most likely have comfort and efficiency problems. You may well have condensation problems. You will be spending a lot of money on a product that likely won't perform as it should. Don't let him leave the vents open. If the installer you've chosen doesn't understand this, you may want to choose someone else. 
I was hesitant to buy this because many reviews stated that it didn't cover as advertised, but after reading/following all directions, everything turned out perfectly. It even seemed to apply slightly more than the 650 bd/ft that was advertised. The application process was very easy to learn and I applied all of the product in about 1 hour and 10 minutes- prep time included. I couldn't be happier and I purchased another kit this morning.
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.  
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 was hesitant to buy this because many reviews stated that it didn't cover as advertised, but after reading/following all directions, everything turned out perfectly. It even seemed to apply slightly more than the 650 bd/ft that was advertised. The application process was very easy to learn and I applied all of the product in about 1 hour and 10 minutes- prep time included. I couldn't be happier and I purchased another kit this morning. 

How Much Is Spray Foam Insulation Per Sq Ft


Roof Coatings should not be confused with deck coatings. Deck coatings are traffic bearing - designed for waterproofing areas where pedestrian (and in some cases vehicular) traffic is expected. Roof coatings will only waterproof the substrates but will not withstand any kind of on going use by people or vehicles (such as walkways, patios, sundecks, restaurants, etc.).
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.
Due to its relatively large cell structure, low-density foam stays somewhat soft and flexible after curing. This increases the likelihood of its continuing to provide high insulation value even as the building settles and shifts over time. Low-density SPF provides heat insulation and seals airflow through cracks, joints and seams by filling the cavities. In addition, this foam can help absorb sound thanks to its soft texture and open-cell structure.
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. http://youtu.be/ggLAUsiuI_o

The Canadian National Building Code references the CAN/ULC S705.2 National Application Standard which must be followed during all installations of 2lb medium density closed cell polyurethane foam. Every installer of CAN/ULC-S705.1 compliant medium density, spray applied foam must be licensed in order to spray foam and hold valid photo ID issued by their Quality Assurance Program (QAP) provider showing their license is in good standing.
I had a hole in the drywall in our bathroom that was about 2 in x 5 in that I used Great Stuff to fix. I am impressed with the characteristics of the filler. It filled the hole completely in a few seconds of application. I will warn anyone using it though to make sure you don't fill the hole entirely flush to the wall because this stuff continues expanding after you apply it. I didn't think about that but no big deal really because you can sand it which is exactly what I did, and then applied spacial and paint and it is almost as good as new. For the price this was a heck of a deal because I only used a tiny amount and now am left with nearly a full can. I guess I will have to find somewhere else to use it now. Great product, ... full review

If your foam pulled away just a little bit, Jamie, and they were able to fix it with just a little bit of touching up, then it wasn't as bad as the house where I saw this problem. As the last photo above shows, it had pulled away significantly from the studs and rafters, and it was all over the house. This was closed cell foam, and interestingly, it didn't pull away from the horizontal framing members, just the vertical and sloped ones. They did some touch up, but that wasn't enough. I don't know how this one ended up getting resolved. I think maybe the contractor came back and sprayed cellulose on top of the foam.

Where Can I Buy Spray Foam Insulation

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