Which Roof Coating is Best?

Roof coating has many benefits.  

When applied correctly, roof coating will lower potential repair costs, protect your roof from the most extreme weather, and drastically extend the life of your roof. Although the lifespan of roof coating depends on its quality, application, roof substrate, and environmental exposure, roof coating protects your facility from damaging effects such as UV light, excess water, and wind.  

However, with so many different types of roof coating, which one is best for shingles?  

The answer is, it depends. Let’s discuss the most common types of roof coatings, their strengths, and their weaknesses.  

Acrylic  

Acrylic coating is an elastomeric coating. Elastomeric coatings are natural or synthetic coatings with elastic properties. This type of coating is a popular choice for sloped metal roofs.  

Acrylic coating is cost effective and long lasting. It is also highly reflective and UV resistant, which helps to minimize the sun’s impact and lower energy costs. Moreover, it is easy to apply with minimal complications.  

However, as acrylic roof coating ages, it loses mil thickness due to constant weathering and exposure to extreme environmental conditions. As such, before purchasing an acrylic roof coating, ensure it has been tested for specific roofing environments and applications.  

Butyl  

Butyl roof coatings are elastomeric liquid sealants that can be applied to flat and metal commercial roofs. Butyl has synthetic or elastomeric qualities that make it extremely flexible and durable.  

Besides its elongation and tensile strength, a butyl roof coating can withstand ponding water and is considered a vapor-retardant barrier due to its rubber membrane. Moreover, it can reflect 80%-90% of the sun’s UV rays.  

Butyl roof coating has a low solid content, which means that once the coating has completely cured, only a small percentage of solid material remains on the roof, and more of the product must be applied. Furthermore, butyl coating is challenging to spray and lacks color stability.  

Polyurethane  

Polyurethane coating is a popular choice for commercial roof restorations and repairs. It provides excellent protection for impact resistance and foot traffic.  

The two main types of polyurethane coatings are aromatic and aliphatic. They are mainly used in combination with base coats and top coatings. 

They offer durability but are not UV resistant when used as a base coat. Typically, aliphatic is used as a top surface because it is UV stable, stays clean, and keeps color longer than other coatings.  

While polyurethane might seem like a safe choice in some areas, it may not be right for areas prone to rain and humidity. This is because the installation process needs several days of perfectly dry weather to set. If the roof coating doesn’t dry completely, it will trap moisture beneath it, which could lead to mold, rot, or poor air quality within the building. 

Silicone  

Silicone coatings are commonly used on residential properties. This highly elastic material provides excellent adhesion to the existing surface, offers good weather resistance, rarely becomes hard or brittle, and withstands long-term exposure to ponding water.  

In addition, silicone coatings provide excellent ultraviolet protection in extreme temperatures and harsh environments and are more oxidation resistant.  

Some major disadvantages of silicone coating are that it easily attracts dirt and is more susceptible to heat from the sun. In addition, silicone roof coating can be difficult on hydraulic spray equipment, making it challenging to spray.  

To learn more about roof coatings, contact a CertainTeed professional today. Our technicians will recommend the best roof coating to ensure your roof maintains its integrity.