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A “one size fits all” approach does not benefit commercial roofing when it comes to deciding which coating to apply to your rooftops. Roof coatings are specifically engineered and depend on the type of material used in your roofing. What all roofing coats do have in common, though, is that each roof coating will enhance the reflectivity of your rooftop. Excellent reflectivity is a tremendous asset for commercial buildings in Austin, as it significantly reduces the cost of air conditioning during the hot, humid summer months.
Roof coating manufacturers design their liquid-applied roof coating products to be compatible with the specific materials to which they are applied. Some are intended for use on bituminous roof membranes, while others have been specially developed for polyurethane foam application or sheet roof membranes. Regardless of type, each roof coating should bond uniformly and firmly adhere to the intended substrate while remaining sufficiently flexible so that it can tolerate any anticipated commercial roofing substrate movement. With this in mind, it should come as no surprise that installing a new roof coating on roofing will require an expert to evaluate the best option available.
Professional roofing contractors will first evaluate the existing roofing structure before considering available coatings and primers to determine the product with the best compatibility.
Using Primers on Commercial Roofing
Most professional roofers will use a primer to help with the adhesion of a new roof coating. Primers are designed to provide a bonding platform between the roofing surface and the roof coating to be applied. Just like with commercial roof coatings, primers themselves vary based on the substrate it’s applied to, average weather conditions of the area, and the type of roof coating that’s going to be layered over the top.
While the primer is used as a primary bonding method between the rooftop and the final roofing coat, it’s not a substitute for thorough cleaning of the existing roof membrane before installing the new roof coating. Primer works best on a substrate that has already been thoroughly cleaned to remove dust, chalking film, grease, or oil that may be present. If proper roof preparation has been undertaken before using a primer and new roof coating, the applications will adhere better, thereby increasing the lifespan of your commercial roofing membrane. Once the primer has been applied and dried, it’s time to overlay a compatible commercial roof coating.
Types of Commercial Roof Coatings
The most common commercial roof coatings are polymer-based, and there are nine general types available for installation. Most often, commercial roofing contractors will utilize one of the following four types of roof coatings in Austin, TX:
Acrylic roofing coats are a common choice, as they have been proven to perform well in a wide variety of roofing applications. Most often, acrylic roof coatings are combined with non-bituminous binders. As acrylic is widely used, roof coatings have been developed to enhance adhesion to a wide variety of specific substrates, including metal, asphalt, and spray polyurethane foam roofing materials.
Acrylic binders can enhance particular characteristics, such as permeability, elasticity, and durability – great if your roofing materials lack a specific strength. The proprietary additives used in commercial acrylic roofing coats can enhance desired characteristics to enable roofing to function better in variable weather conditions, and the flexible formula means they have a broad range of application possibilities.
Another reason they’re commonly used is that they’re easy to handle and apply. However, because acrylic roof coatings are water-based, they’re sensitive to additional moisture and temperature-sensitive until they’ve been cured. Before acrylic coatings can withstand rain or another layer, they need to be dry-to-touch, as this means the top film has likely cured enough to be water-resistant. If water is absorbed before the roofing coat has thoroughly dried, a blistering effect may occur.
Silicone-based roofing coats are most commonly used to create a protective surface on SPF roofing systems. Silicone roofing coats also use a solvent-based formula, which is cured by moisture. Coats of silicone often provide the best weather resistance combined with water-resistance and flexibility. Cured silicone is also extremely breathable, with a permeability rating much higher than other roof coatings. However, silicone has a lower tensile strength, resulting in a relatively soft film once cured, which gives it only moderate resistance to dirt and physical abuse. When recoating silicone, primers may be required in between layers.
Fluoropolymer roof coatings are generally used as a factory-applied film on metal roof panels, though they can be re-applied by professional commercial roofers. On its initial application in the factory setting, it’s applied as a thin film. Though it is a solvent-based roof coating, some manufacturers are now adding water-based derivatives to help with recoating and restoration work. Fluoropolymer, unlike some other roof coatings, can be applied directly to roofing surfaces, as well as directly over previous coats of fluoropolymer paint.
Similarly to silicone-based coatings, fluoropolymer demonstrates weather-resistance. Another advantage of fluoropolymer commercial roofing paint is that it features colored pigments that are fade-resistant. A fluoropolymer coating also resists dirt well and is often used as the top layer by roofing contractors, due to its attractive finish.
Polyurethane coatings also have a flexible formula that allows each coat to exhibit a variety of desirable properties. Typically, polyurethane coatings are built from an organic solvent base, making it an attractive option for environmentally-conscious businesses. Similarly to acrylic, polyurethane binders are known for their high-quality adhesive properties and their compatibility with most generic commercial roofing materials. Polyurethane coatings are water-resistant, highly chemical-resistant, and they have high tensile strength once cured.
If you’re unsure which coat is compatible with your existing roofing structure, give the experts at Longhorn Commercial Roofing a call. We’ve helped to restore many commercial roofs in the Austin, TX, area, and pride ourselves on our range of eco-friendly, long-lasting, and energy-efficient commercial roofing solutions. Request a quote online or contact your local Longhorn office by phone.