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. Coating Services
There have been a few mentions of intumescent coatingsabove, and it would be helpful to elaborate on them. Intumescent coating is a type of paint that will bubble when it is exposed to heat or flames. The bubbles act as a barrier that is relatively flame resistant. The bubbled coating delays the ignition of the spray foaminsulation. Because of this, intumescent coatings have become more common in building and construction.
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. 
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.) Coating Services

The Rubberseal creates a coat that can efficiently reflect heat off the roofs of buildings. It is Energy Star rated, which means it’s friendly to the environment.The spread rate of this product is 60 square feet per gallon at 20 imperial mils. It dries in 2 hours but takes 72 hours to get fully cured. Check the weather forecast before you apply it. Spray Coating Services
We have a 22 year old home located in southeastern georgia where the humidity is very high. In the past 2 weeks our floors have started buckling all over. We have a vented crawl space and the old insulation is drooping from moisture and the wood is wet. We are debating between the "encapulation" method or the spray foam method to repair this issue. Which would you recommend? Spray Coating Services
Thermal barriers come in the form of 1/2-inch gypsum drywall or any material that is proven to have an equal fire resistance to gypsum wallboard. Additionally, alternate assemblies can be used if they have been tested in a laboratory and approved. Ignition barriers are a lower standard to meet, and can be satisfied with a number of different materials. Like thermal barriers, they can be substituted with equivalent fire resistant materials and alternate assemblies, such as an intumescent coating. Spray Coating
Simple – we’ve seen experienced contractors work with the separate nitrogen tanks and spray foam rigs and have one heck of a time. These spray foam insulation kits are quick to learn and simple to use. They’re designed to be easy so you get results the very first time you spray. Thorough Instructions, 24/7 Product Support, and videos make it easy to install. Spray Coating
Appropriate training for personnel who are responsible for conducting the painting procedures is important, which may be from a professional training provider or the product supplier. There are also hazards related to the disposal of wastes and materials that are contaminated with potentially harmful chemicals. Decontamination procedures and Material Safety Data Sheets for various products are important. Safety is improved through: Spray Coating