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.)
Excellent kit for insulating a house. Slow rising foam takes longer to insulate an area as you must do it in layers 1" thick. Any thicker can overheat the chemicals and prevent a proper cure and off-gassing. Recommend purchasing a second suit and nozzles so you can use it multiple days to achieve the thickness desired for the highest R value. Seals up and insulates much better than traditional fiberglass. The sound suppression is noticeably different. Used it to insulate the ceiling above our bedroom. The sound is remarkably more quiet than the fiberglass insulation we had before. The only down side is the weight of the containers. Using a smaller kit would be easier to handle and move around when spraying a ceiling in an attic. A word of caution, use plywood that spans at least 2 joist per container when spraying in an attic to hold the weight.
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.

Spray Foam Roof Insulation

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. 

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.  
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.

Typical roof coating dry film thickness vary from paint film thickness (plus or minus 3 dry mils) to more than 40 dry mils. This means a roof coating actually becomes the top layer of a composite roof membrane and underlying system. As such, the roof coating is the topmost layer of protection for the membrane, receiving the impact of sunlight (both infrared and ultraviolet (UV), rain, hail and physical damage.

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.
Heatlok®, is a high-performance, versatile spray foam insulation designed for residential construction. Its unique formula incorporates recycled plastic bottles and renewable oils to create high-performance, closed-cell spray foam insulation. This polyurethane insulation combines multiple control layers into a single application, saving homeowners both time and money in construction costs. With our innovative technology, Heatlok is developed with 14 % renewable and recycled content, and is the ideal choice for residential construction.

Spray Foam Garage Door

Current guidelines recommend up to 10 inches of insulation in your attic . This is usually added to the ground, rather than the roof line, which results in the loss of your storage area, due to not being able to refit floor boards after installation. By implementing spray foam insulation to the roof line, you regain the lost 10 inches, thus increasing storage, height and practicality.

I am an Architect in Toronto. I am designing a new roof addition to a row house building. Because of existing conditions and the shape of the new roof. It may be easiest to use closed cell spray foam within the areas of the joists. My question is when spray foam is used in this situation do I need to worry about how the joist members may be thermal bridges? It is not common to provide a little bit of rigid insulation to protect the joist members? The additional layer of outboard insulation will require an extra layer of plywood above the insulation which will add to cost.

Our specialty is Urethane sprayed (in place) insulation and roofing. These products have superior insulating performance over traditional Batt Insulating products. Urethane helps seal the structure and won’t leave gaps for drafts. It provides a reliable thermal barrier so heat and cold cant transfer into your home. Spray Foam insulation provides better comfort, adds structure, as it resists mold for a healthier home environment. Overall spray Foam insulation provides better comfort and better in home air quality.
Carefully examine the roof membrane (surface material) for cracks, tears, blisters, evidence of ponding, exposed foam, and open seams. If already coated, evaluate the condition of the coating. Pay particular attention to areas around roof penetrations (vents, skylights, pipes, etc), ponding areas, cracks in parapet walls, and the attachment of roof membranes to parapet walls. Roofs should be in good condition to warrant coating.

Roof Bond