Silicone based coatings can be spray or roller-applied, and should utilize a medium-nap roller when rolled. These coatings are applied anywhere from 2 to 3.5 gallons per 100 square feet, depending on the substrate. Silicone has two major advantages over the other four types of coatings that should be considered when searching for the best roof coating: 1) it can resist ponding water for extended periods of time and 2) it can adhere to most substrates without a primer. Because of these two major advantages, silicone is the best roof coating that satisfies both quality and cost-effectiveness.

Spray Foam Crawl Space

Although spray foam insulation has been in use since the 1940s, primarily for aircraft, for the past 30 years, continual product innovation has seen the increased adoption of spray foam insulation in residential and commercial construction. The rapid growth of sprayed foam insulation in building construction, thanks in part to its immediate and long-term benefits, has allowed the insulation material to sit confidently alongside traditional insulation types in providing thermal comfort for building occupants.

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).

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.
The local foam installer that I used here in Hilton Head told me he looked for some peeling back of the foam. This was ensuring that it was at the perfect temperature which helped them maximize their yield (profit). I have open cell foam and it pulled away a little, and did so immediately (within minutes). They went back after they were done to any spots that pulled away too much and filled them with the touch up kit; they were looking for the top edge to roll just a little bit.
I have to insulate my walls at the end of this week. That does not give me time to procure slow-rise foam, so my stud cavities will be filled with foam before I'm ready to fill the corner voids. I will not be able to drill straight through the corner studs. Instead, I will have to remove material where the studs meet. What sort of tool do you envisioning me holding while I create space to pump foam into my 1972 corner voids?
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.
When it comes to insulating the house, fiberglass tends to be the common form of insulation. However, after comparing fiberglass and spray foam insulation, it’s shocking how fiberglass tends to be the lesser of the two. Although it has deemed reliable over the years, there are way more benefits to insulating your home with spray foam. One of those benefits includes regulating the temperature of your house.
Polyurethane is a closed-cell foam insulation material that initially contains a low-conductivity gas in its cells.[5] As a result of the high thermal resistance of the gas, spray polyurethane insulation typically has an initial R-value around R-3.4 to R-6.7 per inch.[5] In comparison, blown fiberglass typically has an R-Value of only R-3 to R-4 per inch.[6]

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...

How Much Spray Foam Garage