A few days ago, we posted a blog about the 6 common commercial roofing materials. Today, we’d like to cover a few common commercial roofing protective coatings. In general, there are nine types of polymer-based roof coatings. A few common coatings used by commercial roofing contractors include acrylic, polyurethane, silicone, and fluoropolymer.
Acrylic Coatings
Acrylic roof coatings typically are acrylic blinders dispersed in water and sometimes in solvents with pigments and several proprietary additives. Acrylic roof coatings are a well-established coating with proven performance in a wide range of applications. Acrylic polymers are the most commonly used of the high-performance non bituminous binders. There are many acrylic binders used in the roofing industry to produce products with significantly different properties. Acrylic binders may be selected to enhance adhesion to specific substrates, such as asphaltic surfaces, metal or spray polyurethane foam. Different binders will produce coatings of varying elasticity, hardness, permeability, durability, and so on. Proprietary additives may then be added to perform specific functions or act in a general-purpose fashion over a wide variety of roof substrates and conditions. Because of this formulation flexibility, broad application possibilities, and easy handling and installation, acrylic binders are the predominate elastomeric material used in roof coatings.
Because acrylic coatings are water-based, they typically are sensitive to moisture until they have cured; they at least need to be dry to touch and preferably cured to the point of accepting another coat before they can withstand rain. Once the film has cured, the film becomes more resistant to water. However, most acrylic coatings absorb enough water to create blistering and adhesion issues if the water stands on the cured film for extended periods of time. Most acrylic roof coatings are considered to be breathable and exhibit a typical perm rating of 5.0 to 10.0. All water-based products, including acrylic coatings, are also sensitive to temperatures until they are cured.
Polyurethane Coatings
Polyurethane coatings can be formulated to provide a wide variety of properties and are developed out of an organic solvent base. Overall, polyurethane binders demonstrate high quality adhesion properties that are compatible with most roofing materials and exhibit high elongation and tensile strength, meaning they are strong and durable. They demonstrate a high chemical resistance to many materials and good water resistance. The cured roof coatings can be used as a significant part of many commercial roof coating systems.
Silicone Coatings
Silicone coatings are typically moisture curing, solvent-based formulations. Silicone coatings demonstrate excellent weather resistance, good water resistance, and good elongation with the low tensile strength to be relatively soft in the cured film. The relative softness in the cured film tends to pick up dirt over time and has modest resistance to foot traffic and physical abuse. The cured film is breathable with perm ratings in the range of around 15. The primary use of a silicone coating in roofing is to provide a protective surface for SPF roof systems. In order to recoat a silicone roof coating, a primer may be required before adding the additional layer of silicone coating.
Fluoropolymer Coatings
Fluoropolymer paints have been used in roofing applications as a factory-applied film to metal roof panels. The typical fluoropolymer binder has a solvent base and is applied in a thin film to the metal panel and cured in the factory. Recently, some of the manufactures of the fluoropolymer binders have introduced water-based derivatives of the original polymers, opening up the recoat/restoration market for the technology. Fluoropolymer coatings may be applied over the original fluoropolymer paint finishes and over other roof surfaces, as well.
Fluoropolymer coatings demonstrate weather resistance and modest elasticity, and the colored pigments in the coating allow for the color to last longer and prevent fading. The coating also resists dirt pick up while retaining their solar reflectance well. All of these properties indicate that fluoropolymer coatings typically are used by commercial roofing contractors in finish coats as the last step of the restoration system.
If your business is located in the trans-Atlantic area in Virginia, give Shencorp a call today to get started. We would love to protect your commercial roof with protective coatings to keep your roof alive as long as possible. Let us help!