The problem was that the installer was doing his first spray foam job ever, and the thickness of the insulation varied from zero (visible roof deck) to about 9". Unfortunately, good average thickness doesn't cut it. The coverage needs to be uniform because a lot of heat will go through the under-insulated areas. (See my article on flat or lumpy insulation performance.)

Spray Foam Companies


A. You can use closed-cell spray foam that way if you want, although you should realize that the spray foam will prevent the roof sheathing from drying inward. This approach should only be used if the roof sheathing is bone dry, because it will never dry when sandwiched in this manner. Most building scientists would prefer to see fiberglass rather than closed-cell spray foam under the roof sheathing in this type of assembly.
The problem you saw with the closed cell foam pulling away like that is due to the heat of the foam was to hot. It was actually curing out and making foam before it could adhere to the wood. The installer wasn't reading his foam correctly. He should of stopped and turned down the heat on his hose temp. Also installers have to be aware that as the sun rises and the temp in attics rises the subtrates get hotter as well. This will cause the installer to adjust his heat when installing the foam as the temp changes thru out the day.  

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Good article, but it seems like you can chalk up almost all of those problems to the experience level of whomever is spraying the foam. Spray foam isn't an inherently bad product, but it's pretty easy to botch if the hired company is inexperienced. Fiberglass may be foolproof to install, but then again it has a terrible R-Value compared to a good spray foam. People just need to get referrals and do their homework whenever they research a spray foam contractor. http://www.youtube.com/e/ggLAUsiuI_o?app=desktop
This tropic heat actually is the cause that the steel structure, which most roofs in that part of the world are built on, expands and contracts all the time. By doing so, the sun-battered steel structure causes the roof tiles to dislodge and slowly creates small openings between the roof tiles, through which rain water can run into, creating leaks that can cause much damage to plastered ceilings and electric wiring.
If you’re not familiar, spray foam is a type of insulation that expands after you spray. The foam expands and seals, avoiding any type of unnecessary moisture (which can create mold) or encouraging pests to eat through your walls. It protects the lining of your house, and even can protect the heating and cooling of your house during those unbearably cold or hot days. 

We live in middle TN and had our house foamed last year. We noticed recently that some of the foam was shrinking and seperating from the floor joists. We contacted the installer and he informed us that the manufacturer had a problem with a batch of foam during the time frame we had our house sprayed. The contractor wasn't sure if we had the recalled batch installed in our house or not. He said he would check the batch numbers and let us know. He seems like a nice guy promising to do whatever it takes to fix any problems. Do we trust him, however, to be truthful about the batch number? Do we have any options for finding out the information ourselves? I inspected the entire crawl space of the house and noticed approximately (5) areas that were seperating and a couple areas where the foam didn't adhere to the block. Do I assume by it being so infrequent that it is nothing to be concerned about? My concern is the walls that are not capable of being visually inspected because of sheetrock.
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.
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. https://www.youtube.com/watch?feature=youtube_gdata&v=ggLAUsiuI_o
Spray foam insulation, like other insulation, saves on energy costs and lowers utility bills. Studies by the US Department of Energy show that 40% of a home's energy is lost as the result of air infiltration through walls, windows and doorways. Buildings treated with spray foam insulation insulate as much as 50% better than traditional insulation products.
What more is that we also think it is one of the most durable among liquid roof coatings on the market. It can last for several years, working continuously in protecting your roof from outside elements, such as dust, leaves, twigs and debris that would otherwise damage your roof. When it happens, your roof might have leaks and cause discomfort inside your RV.

Where Can I Buy Closed Cell Spray Foam

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