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.) 

OK, Peter, I finally went back and read Alex Wilson's article on what he perceives as a serious problem. I haven't seen the full report, but based on the summary he wrote on the Green Building Advisor website, I question the science. It seems to me that he's chosen the wrong metric and he's basing his conclusion on too many assumptions because he doesn't have enough data. You can see my comments at the end of his article.
One of the high-tech insulation products being utilized these days is a foam-spray product called "Icynene," which is a foam that starts as two liquid components (a and b, if you will) that are heated up and sent through two hoses and meet at a tip of a gun where the magic begins. This is a thin film that expands to 100 times its volume in eight seconds, when it's permanently set up.

Spray Foam Exterior Walls

Thoroughly clean the roof surface. Roofs collect oils from asphalt, chimneys, and cars plus lots of dirt and dust. Coatings don’t stick well to any of these. We recommend cleaning with an inexpensive solution of TSP or TSP Substitute in a bucket of water (follow label instructions). Use a broom to scrub ponding areas and areas of peeling coatings. Work a section at a time and hose off the dirty water. Sweep away puddles to promote drying. Do not allow wash water to dry on walls, furniture, windows, and visible surfaces. 

Foam is very sticky; you'll need to wear disposable coveralls with a hood, and gloves, a face mask, and eye protection. It takes some practice to spray foam evenly and, because it expands so dramatically, to control its depth; 2 inches is all you need to seal the joist cavities. You need a clear area so that you can work without interruption; any pause longer than 30 seconds will clog the nozzle and require putting on a new one. It's also critical that the air temperature stays between 75 and 85 degrees.
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.  
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I employed a company to insulate my three story house in 2011. They started Insulating it in August of 2011...They said it would be a 3-4 day job. They installed it in 0.5"-8" lifts all in the same cavity, this left burned insulation and voids. They removed what they told me was the bad insulation and in the process cut many electrical wires. They fixed this. They then reinstalled too thick again in some spots and removed again. They then installed it for a 3rd time. The areas that I thought were good are now separating from the structural members leaving voids. As of October 2012, 1 year and 2 months of dealing with the contractor I told them I want proof that what has been installed carries a warranty or I want my money back and I will fix the problems myself. They have yet to provide me with this warranty. I have spent many hours in the house looking at what is bad and they need to fix. I am frustrated, 14 months of additional rent due to their negligence. I would like to know how I can get proof that the product carries the manufacturers lifetime warranty, or has it been installed improperly throughout the entire house. Desperately awaiting your response. 
Fill and seal expanding foam sealant is urethane Fill and seal expanding foam sealant is urethane foam designed to fill large areas quickly and permanently. Uses include filling holes cracks or gaps that require a complete airtight and waterproof seal but are too large to be filled with ordinary caulk. The foam expands approximately 3 times its original ...  More + Product Details Close
If you haven’t considered spray foam insulation, now may be the time to start looking into it. As you know, having proper insulation will help reduce your heat and air conditioning bills. In specific, spray foam insulation can be particularly helpful during renovations. It can provide a barrier between outside walls, and even a sound barrier for the inside.

Global warming potential (GWP), as defined by the EPA, is a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period of time, relative to the emissions of 1 ton of carbon dioxide (CO2).  Spray foam insulation products that use water as the blowing agent - typically open-cell foam however Icynene’s ProSeal Eco is a 100 percent water blown closed-cell spray foam – have a global warming potential of 1, the lowest possible number.  This is because water in the mixture reacts during the application process to release carbon dioxide and heat. The GWP of the blowing agent is that of carbon dioxide. Carbon dioxide has a GWP of 1.

Spray Foam Basement Walls

We love the Heng’s rubber roof coating because it is versatile enough to work on the RV roof and protects it from the elements longer than other products do. Plus, it is useful enough to be used in sealing seams and tears. Versatility does matter when shopping around for an RV roof coating. It ensures more uses, meaning more value for the money. That said we don’t need to buy a separate product to perform the tasks.
Part of that guidance will be explaining that interior, two component foam is applied with the professional using specific personal protective equipment (high-pressure foam is installed while using a respirator, for example). It is encouraged that professionals explain clearly to customers that this equipment, coupled with certain work and engineering practices, including ventilation, is used to minimize exposures to the chemicals used to make SPF during the job.
Acrylic coatings are typically applied in two coats, with the second running perpendicular to the first. 1 gallon per 100 square feet is a good estimate for these coatings, as they do not need to be applied nearly as thick as many other coatings. These coatings can be sprayed or roll-applied. Acrylic coatings generally require a re-coat within 2-3 years of application.
One thing I wanted to mention was that I think your price point is a little high and that might deter people from considering spray foam. As a project manager for a spray foam company for years I can tell you that we offer 0.5 Lb. open-cell foam at around $.25/board foot. We even offer a 1.0 Lb. open-cell foam for less/the same cost as you quoted the 0.5 Lb. foam for above. The 1/0 Lb. open-cell foam has an R-value of almost 5.
Spray foam insulation is typically priced by volume, meaning your cost will depend on how much material you need to use to insulate your space, although other factors may influence price as well. In most cases, the cost of spray foam insulation is more than worth it, as it's a once and done upgrade that will not only provide energy savings in your home, but also improve your home's overall comfort. 

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