Pros and Cons of Different Roof Coatings Amir Khan, SVP Research and Development, ICP Building Solutions Group Roof coatings are an important way to protect and maintain roofs in residential and commercial settings. They are available in a variety of materials, popularly ranging from asphaltic blends to acrylic elastomeric, polyurethane and silicone coatings. Each type offers different advantages and disadvantages for roofing contractors and their clients. This article provides an overview of the various types of roof coatings, along with their individual strengths and weaknesses.
Know Your Roof Coatings
Roofing contractors must naturally consider the type of roof they are working with, the climate of the region and the specific needs of the home or building when choosing a roof coating. Understanding the material composition of the roof, how the environment will affect the coating and the desired performance of the product helps to narrow down the best options. Roof coatings form a durable and often reflective surface on built-up, modified bitumen and asphalt roofs as well as concrete, metal, wood and many other types of surfaces. Many of these products can be quickly and easily applied using a professional brush, roller or spraying equipment. Contractors should do their own research and consult their peers about the different types of roof coatings and their associated benefits and limitations that are broadly discussed here. One advantage that all coatings have in common is they do not add dead load to existing roof systems because they do not count as additional layers for code purposes, thereby avoiding the cost and complication of tearing off, disposing of and replacing an existing roof. Always be sure to evaluate repair and restoration options before deciding to replace an old roof because coatings offer many benefits, including the opportunity to improve your profits by keeping your crews moving quickly from one job to the next. Also note that because many roof coatings are rolled or sprayed on, application can require a steady hand and trained eye to avoid filling up any fissures in the roof that might include vents and drainage openings, which can lead to problems like clogs as well as lumps, bumps and other minor imperfections in the finished roof surface. Take time to consult with the coatings manufacturer or other trusted expert if you have any questions concerning proper installation of roof coatings.
Asphaltic Blends
One of the most common types of roof coating, asphalt coatings are manufactured with select asphalt and solvent blends and are popular for their good weathering qualities such as resisting the damaging 30
FLORIDA ROOFING | July 2023
effects of heavy rainfall, large hail, snow or ice accumulation and UV radiation. These coatings are also preferred for their low-tomoderate cost compared to other types of roof coatings, combined with their fast and easy applicability. These advantages have made asphalt roof coatings the industry-standard choice and backbone of countless successful businesses for decades. Their flexibility is further appreciated by contractors who commonly use them to seal other surfaces like foundations and retaining walls.
Asphalt coatings can be black or aluminized where a reflective and UV-stable coating is needed.
Asphalt roof coatings are susceptible to heat damage and can become brittle with age, so they may not be as effective or long-lasting as other types of coatings when applied to certain substrates. This means asphaltic blends may not be ideal in areas of the country that experience extreme high temperatures or greatly fluctuating hot and cold cycles. Poorly applied, these coatings can trap moisture and create a breeding ground for mold and mildew, so it is important for crews to have some experience installing them. They also tend to be less reflective than other types of coatings, so owners may not experience the full benefit a “cool roof” can provide in terms of energy savings. Many asphalt coatings contain varying quantities of aluminum flake to make them more reflective; however, average solar reflectance (between 45 to 50 percent) is marginal relative to what is commonly considered a cool roof (80 to 90 percent reflectance). Asphaltic coatings are generally safe to work with; however, some formulations may emit volatile organic compounds (VOCs), making it important to ensure that the product being specified will comply with all federal, state and local VOC regulations. Warranties