Fluid-applied asphaltic rubber membrane system. The aliphatic coating is used as a top surface because it is UV stable, stays clean, and holds color longer than other coatings.Ĥ. The base coat material is durable but does not offer high UV resistance. These types of materials are typically used in combination of base coat and topcoat. There are two types of polyurethane roof coatings: aromatic and aliphatic. Polyurethane coatings provide the best rates of all coatings for impact resistance and for foot traffic. They are now used as coating applications over a variety of existing roof membranes. Polyurethane coatings were initially developed to be applied over sprayed-in-place foam roofs. Silicone also holds dirt on the surface and loses reflectivity over time.ģ. Some of the drawbacks are cost, application requirements, and the fact that there are only a few materials – other than silicone – that can be applied directly to the silicone surface. Silicone is available in a variety of colors and provides high reflectivity and emissivity ratings. Silicone coatings also provide excellent ultraviolet protection in extreme temperatures and harsh environments and can resist oxidation. The rise in applications is primarily due to the material’s ability to withstand long-term exposure to ponding water, as most of the other coatings cannot withstand ponding water. Silicone coatings have gained market share on the commercial roof market in the last decade. Silicones provide good weather resistance and rarely become hard or brittle. It is a highly elastic material that provides excellent adhesion to the existing surface. Silicone coatings are manufactured with a high solids’ dispersion of 100 percent silicone. This reduces the cure time of the acrylic coating to a few minutes, thereby eliminating the possibility of coating run-off if there is precipitation directly after application.Ģ. Several acrylic coating manufacturers now offer instant-set materials. These coatings also, however, lose mil-thickness from weathering, require application in ambient temperature of above 50 degrees F, and cannot withstand ponding water. Ideal curing takes place with warm weather and low humidity.Īcrylic coatings are economical, provide excellent reflectivity, and are easy to work with. Cure time of these products is highly weather-dependent and cold weather or high humidity will impede curing. Acrylic coatings should not be applied in freezing temperatures or when precipitation may occur within a specified period from application. Most manufacturers provide warranties based on the coverage rates extended warranties require additional coverage. Some studies have indicated that properly formulated acrylic coatings can reduce surface temperature as much as 20 degrees F when exposed to direct sunlight at 85 degrees F.Īcrylic coatings are manufactured of 100 percent acrylic and can be applied in one or more coats. Acrylic-based materials provide excellent resistance to radiation and hail damage and have the inherent flexibility required to withstand dimensional instability of most roof membrane surfaces. These types of coatings are now used on a variety of roof membrane surfaces, including single-ply membranes and metal systems. Acrylic coatings: Acrylic coatings were originally developed to provide ultraviolet protection for sprayed urethane foam applications. Also, all pre-application preparation should be completed in accordance with the roof coating manufacturer’s requirements.ġ. This article covers four roof coatings: acrylic, silicone, polyurethane, and an asphaltic rubber membrane system. Not all coatings are acceptable or compatible on all roof surfaces. The material formulations, uses, and application methods are all different, so facility managers should examine the manufacturer’s material data sheets to determine which product is suitable for their specific project. There are several types of coatings available on the commercial roofing market.
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