The most common types of roof coatings are acrylic coatings, asphalt coatings, polyurethane coatings, and silicone coatings.
Acrylic water-based coatings are ideal for high UV environments where a reflective roof is desired. They can be colored, but generally are sold in white, tan, and grey. Many specialized versions are made to be compatible with specific substrates.
Asphalt coatings are either solvent based “cut backs” or emulsions. They can be black or aluminized. They have the ability to be used in cold and inclement weather. Aluminized coatings are used when a reflective and UV stable asphalt coating is needed.
Polyurethane coatings are typically solvent based and come in two main types, aromatic (less UV stable) and aliphatic (very UV stable). Urethanes have good mechanical properties and high abrasion resistance. They are suggested for use in hail prone regions or where a roof is exposed to heavy foot traffic.
Silicone coatings, like acrylic coatings, perform well in high UV environments where a reflective roof is desired. Often silicone is used in locations where rain is a daily occurrence, or if the roof is often wet and experiences excessive amounts of ponded water.
Other Types of Roof Coatings
Roof coatings can be made with other resins or combinations of resins. These include, but are not limited to, butyl resins, fluoropolymer, PMMA, polyester, silyl terminated polyether (STPE), polyuria, PUMA, SEBS, and styrene-acrylics.
Cold Applied Roof Coatings
Cold-applied coatings and cements are those that are designed to be used at ambient temperatures, requiring little, if any, heating to facilitate application. Typically, they are comprised of a resin, a carrier solvent, reinforcing fillers, and optional reflective pigments. Upon application, the carrier solvent evaporates from the coating, leaving a cured, water resistant film.
Bitumen roofs are one of the longer lasting types of flat roofing materials, easily lasting 20 years or more. Regardless of how the material is applied (self-adhesive sheets, hot-mopped asphalt, or cold-applied adhesives) the seams are usually melted together which help stop leaks.