What Are Roof Coatings
Roof coatings are designed for protecting and extending the useful service life of roof assemblies for new construction and more commonly, existing roof coverings, such as BUR, metal, modified bitumen, single ply membranes, and spray polyurethane foam.
Roof coatings are thicker than paint and have a higher solids content. Roof coatings are formulated to protect roofs from the damaging effects of weather and the environment, such as UV light, and excessive water and wind. They are formulated to provide protection for many years and are also extremely elastic; they typically contain a high level of top-quality resin. The high quality resins and the volume of resins introduced during manufacturing allow the coating to maintain its elastic properties throughout its lifecycle. Once cured, these resins form an elastomeric and durable film, which provides an additional measure of waterproofing and allows the roof coating to bridge small cracks and membrane seams found on roofs. Unlike paint, which is typically applied in portions of a gallon per 100 square feet, roof coatings are applied in terms of multiple gallons per 100 square feet. Today, there are various types of roof coatings on the market that can benefit any type of roof.
Types of Roof Coatings
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.