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.
Charles: That photo is closed-cell SPF, and it's not sprayed perfectly uniformly. As long as it has the minimum thickness required (3" on a ceiling here in the Atlanta area), it should be fine. I've discussed some problems with SPF installations in the articles listed in the Related Articles section above. This photo is from about 10 years ago, though, and has no ignition barrier.  
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...

The process typically operates at 39–120 °C to avoid thermal damage. It can induce non-thermally activated surface reactions, causing surface changes which cannot occur with molecular chemistries at atmospheric pressure. Plasma processing is done in a controlled environment inside a sealed chamber at a medium vacuum, around 13–65 Pa. The gas or mixture of gases is energized by an electrical field from DC to microwave frequencies, typically 1–500 W at 50 V. The treated components are usually electrically isolated. The volatile plasma by-products are evacuated from the chamber by the vacuum pump, and if necessary can be neutralized in an exhaust scrubber.

I've seen this only once, and it was with closed cell foam, but I've heard of it happening with open cell foam, too. I don't know the details, but I've heard it could result from a bad batch of chemicals, improper mixing, or too high a temperature. Whatever the cause, it's not a good thing. The photo below shows how the spray foam pulled away from the studs. A little bit of uninsulated area like that adds up to a lot of heat loss/gain when the whole house has that problem, as it did here. 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.

I applied this product on a rolled asphalt flat patio roof. It was over 90 degrees and I could not touch the roofing at all on the first coat. I was laying on layers of cardboard to apply the silicone under the gutters and then rolled the first coat. The next day I brought all the cardboard to apply the coating under the gutters. I accidentally touched the roof and it was cool‼️  I threw the cardboard off the roof, laid down to do the gutters and roll the second coat. I was amazed how well this sealed and cooled the patio. I am going to apply this to my other patio and covered parking which are metal. I can’t wait to apply for sealing and adding cooling to these areas. Roof Coating Supply answered all my question and they ship promptly - I had my order in 3 days. Thank you. Spray Coating Services
This is in great contrast to my friend's experience. Her attic spaces were sprayed and the foam is actually pretty, and I was in her attic 6-7 days after it was sprayed and could hardly smell anything when I stuck my face up to the foam. And she did not have to clean up one speck of dust during or after the spraying. I got the name/number of the guy from her who managed her attic project, but between the time he did my house and the time he did her house, he was let go from the company who did her attic and hired by another company. He assured me everything would be the same, etc., etc., and I had no reason to believe anything had changed, but the sprayers who did my house later admitted they had never sprayed an attic before and I also found out that the foam used in my attic was from a different manufacturer. Neither my friend nor I had any idea this guy was with different company then, until the week after they filled my attic with off ratio foam, and my home with toxic vapors.   Spray Coating
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Ever wonder why it's so hot and wet inside a metal building that has spray foam insulation, in the summer and so cold and wet in winter? The metal skin magnifies the heat of the summer and frigid temperatures of the winter. Metal is a very good conductor of heat and cold. In hot weather, metal framing and sheeting rapidly radiate the sun's heat into a building. In cold weather it rapidly releases the heat out of your building. When warm air comes in contact with the cool metal sheet, condensation occurs. 
Mass-produced material is loaded on a conveyor belt where it is fed into one of these flatline machines. Flatline machines are designed to specifically paint material that is less than 4 inches (10 cm) thick and complex in shape, for example a kitchen cabinet door or drawer front. Spray guns are aligned above the material and the guns are in motion in order to hit all the grooves of the material. The guns can be moved in a cycle, circle, or can be moved back and forth in order to apply paint evenly across the material. Flatline systems are typically large and can paint doors, kitchen cabinets, and other plastic or wooden products. Spray Coating Services
As this example illustrates, it's important to seal the envelope completely. One of spray foam's biggest selling points is its air-sealing ability, but it can't seal places where it's not sprayed. One of the nice things about using spray foam in new construction is that you can do a Blower Door test before the drywall goes in. Even better, you can test for leaks with a fog machine.
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: Coating Services
The Barrier product family is EPS foam under The Barrier product family is EPS foam under slab insulation and vapor retarder in a roll designed to insulate radiant heating projects from heat loss and retard moisture migration through concrete. The core of the product is made of flexible recyclable expanded polystyrene that provides excellent insulation characteristics that are ...  More + Product Details Close

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 Coating