Warning: EnergyGuard™ Elastomeric Roof Coatings can freeze below 32° F. This is because the product is water based. In case of freezing temperatures, stop the application process. After application, you must allow the product time to dry before exposing the elastomeric roof coating to foot traffic or water. You should also cover the containers and dispose them responsibly after application. In case you or someone else i.e. a child ingests the coating seek immediate medical attention. Don't induce vomiting.

I used this for the rim-joist in our home. A couple things: I put 1in solid core foam (cut to size) in each bay before using the spray foam. I also was able to do a relatively 'thick' spray to close off any potential gaps that may have existed. I turned off the HVAC and turned on some fans in the windows to exhaust out the fumes, and wore a mask (3m respirator). http://www.youtube.com/watch?v=ggLAUsiuI_o&feature=youtube_gdata
A: The RV roof coating works by waterproofing, weatherproofing and sealing our RV roofs from elements, including rain, snow, wind and other outer forces. It can also resist impact from leaves, twigs, dusts and other things that would otherwise damage the roof. It also works by reflecting UV rays, keeping the roof from degradation. The roof coating can also prevent leaks, heating and cooling loss and discomfort in our RV.
I did a LOT of prep before using this product. Cleaned, vacuumed, installed additional insulation etc etc etc. This spray foam was easy to work with, and did it's job as it was supposed to. If you are curious, this kit was purchased because - every "foam insulation company" I contacted either did not call back (due to no interest) OR this was too small of a job. That is why I went DIY on this one, that and: I was advised by one of these companies that they have a minimum $2k job because ... (insert your answer here, but I will choose that everyone needs to eat).
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. http://www.youtube.com/watch?feature=youtube.be&v=ggLAUsiuI_o

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.
Note: The practice of foam insulating the attic has raised eyebrows in the building industry because "standard" roofing techniques call for the attic to be ventilated; however, in a vented attic situation it will become approximately 130 degrees in the summer. There's no reason for an air-conditioning and vent-ductwork to have to work in that type of severe conditions. By applying Icynene right on the underside of the roof deck, the severe temperatures no longer exist in the attic. In short, the attic is now a "conditioned" space of the house that is just as comfortable as any other room in the home. This is called a "Compact Roof", which means you can frame right up against it. The one drawback of using expanded foam on the inside of the roof is that this will cause the temperature of the shingles to rise, but how much is not yet known. And how much damage a rise in temperatures could cause is debatable.

Roof Spray Foam Insulation