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."
Open cell spray foam consists of cells that do not completely seal themselves. This makes for a softer and less dense final product. Closed cell foam cells are completely sealed and closed compressed together, creating a denser and firmer final product. This also gives closed cell foam a higher R-value (measured unit of thermal resistance). These differences also affect the cost difference between the two types of insulation.
Polyurethane Spray Foam Insulation is used in industries ranging from mining to movies, from cold storage to marine flotation. Spray Foam Insulation’s ability to seal out air and insulate quickly means it’s always in high demand for residential and commercial applications. Spray Foam Insulation is critical for solving our nation’s energy challenges because it dramatically reduces the energy needed to heat and cool our homes and offices.
Roof Coatings should not be confused with deck coatings. Deck coatings are traffic bearing - designed for waterproofing areas where pedestrian (and in some cases vehicular) traffic is expected. Roof coatings will only waterproof the substrates but will not withstand any kind of on going use by people or vehicles (such as walkways, patios, sundecks, restaurants, etc.).
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.