Yes, you're right that all of the problems mentioned above are related to the installer. I didn't try to hide that and even used the word 'installer' in two of the four headings. I can see how you'd think that the title is misleading, but in the end you can't separate spray foam insulation from its installation. Some people have the mistaken impression that if you get spray foam in your house, your home will outperform all others. My point here is that that's not true.
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.
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.
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).
However, coating asphalt shingles and built-up composition roofs requires more caution. The National Roofing Contractors Association’s (NRCA) director of technical services has stated "The roofing industry is aware of a number of issues that could have negative consequences for field application of coatings over asphalt shingle roof systems. Anyone considering this type of application should be aware of the concerns so they can weigh them against the benefits claimed in coating product promotional materials."[2]
Note:  A board foot is defined as a 12" x 12" square at 1" thick. Actual output can be affected by a number of factors including temperature and humidity. The theoretical yield has become an industry standard for identifying certain sizes of two component kits. Theoretical yield calculations are performed in perfect laboratory conditions, without taking into account the loss of blowing agent or the variations in application methods and types.
For large jobs, professionals such as Dr. Energy Saver use two-part foam, which comes in larger containers. With 2-part spray foam, it's necessary to mix separate resin and catalyst compounds at the application nozzle. Combining these ingredients starts a chemical reaction that creates expanding foam. Contractors use small 2-part foam "kits" to air-seal an attic or to seal and insulate ductwork. To insulate an entire attic or wood-framed wall with spray foam, the resin and catalyst compounds are pumped to the application nozzle from 50-gallon drums in a specially equipped truck.

Roof Coating