There are some spray foam contractors that write contracts with vague language. Example: "spray apply elastomeric top coat to roof." This contract doesn't mention what type of material is being used, what rate, and what is the ending thickness of the material. Most manufactures use formulations (especially acrylic coating) that are 50% solids by volume. This means that one gallon of coating will yield 8 dry mills of coating on the roof. Also, watch out for spray foam contractors using brochures from one manufacturer and using materials from a different manufacturer.
Another thing to watch out for, are Spray foam contractors that say they are putting down a certain foam thickness and don't. Rule of thumb, if you don't see the spray foam contractor crew probing the spray foam, you are not getting the spray foam thickness you paid for.
I have found that Spray foam contractors who offer one inch of spray foam, as there completed thickness; means you as the customer never get one inch of spray foam. These spray foam contractors should be applying no less than one inch, but usually that is the maximum amount that is provided, and most areas are less than one inch thick.
A one inch minimum of spray foam was developed by the SPFA (governing body over spray foam) and should be only applied over a smooth surface. Since spray foam contractors' foam thicknesses will vary ¼" from highs to lows, you need to make sure the spray foam thickness is never less than one inch. Along the same lines, a 1 ½" minimum is required over an irregular surface and 2" minimum is needed to stop condensation in roof applications.
Also, you have to watch contractors who use long warranty years to sell contracts. This makes you believe, the longer the warranty the better and therefore entices you to buy. The standard warranty from coating companies is 10 years. Therefore, this is the standard warranty you should find on spray foam contractors' contracts. Warranties of greater length always have more coating applied to the roofs, or the contractor has proven to be a master applicator with that roof coating company.
A standard 10 year warranty will be around 30 dry mills of coating on the roof, + or – this amount depending on manufacture. Therefore, longer warranties will have greater thicknesses. Usually, another 10 mills of coating will yield another 5 years, or a total of 15 years. Very few, if any, offer greater than 15 year warranties. Warranties after 10 years, with minimum coatings, are considered to be the most risky.
So, Spray foam contractors who give ambiguous language are ones to stay away from. Think about it, if you don't know what product is stated in the contract and the spray foam contractor will not stand behind the work, who do you go after for help? Remember, if it's too good to be true, it probably is.
