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The Evolution of Roof Coatings

December 21, 2021 4:20 pm

Roof coatings have been around for centuries. Even the Egyptians applied coatings like beeswax for waterproofing. Over the years, coatings have been used to maintain existing roofs or applied over new roofs, and have gained popularity thanks to their time-tested, proven performance.  

Just how time-tested? Watch this webinar to learn about the history of coatings, from inception to today’s modern coatings, uses, and benefits. 


Did you miss our other webinars? Check out how to choose the right type of coating and the economic and environmental impact of coatings.

History of Modern Coatings

The first use of a liquid-applied coating dates back to at least the fifth millennium B.C., about 7,000 years ago, when tar was used over thatched roofs to waterproof structures. 

Fast forward to the seventh millennium B.C. and Egyptians were using a mixture of beeswax, gelatin, and clay to create a waterproof varnish. Cold process roof coatings likely entered the picture in the seventh millennium. 

In the 19th century, coatings evolved to include reinforced tar or asphalt, which is most similar to modern-day built-up roofs made of layers of asphalt and ply sheets. 

It wasn’t until the last 70 years that today’s coatings — acrylic, silicone, and urethane — made an appearance. The emergence of these coatings was driven by safety concerns and a global movement toward reflective, cool roofs.

Today, these three coating materials dominate the market. They’re used as maintenance coatings over new or existing roofs.

  • Acrylic coatings add life to a roof while also transitioning it to a reflective surface, as acrylic coatings are highly reflective. Acrylics are most popular in high heat, low humidity environments where ponding water is not a concern. 
  • Silicone coatings are an exceptional weather barrier and are especially popular where moisture is a constant threat. They’re U.V. stable, waterproof, highly flexible, and resistant to ponding water — great for a low slope or flat roof repair or restoration.
  • Urethane coatings excel in durability, impact, and chemical resistance. They surpass both silicone and acrylic in terms of tensile strength and stand up well to extreme weather.


Popularity of Coatings

The popularity of coatings has continued to rise since its origination thousands of years ago, and the demand is now higher than ever.

“The increasing construction activities across the globe, coupled with the rising population and changing lifestyles are propelling the growth of the roof coatings market,” according to Reports and Data via GlobalNewsWire

Today, coatings represent 20% of the commercial roofing market in square footage, second only to TPO. Coatings are expected to grow at 6–8% over the next three years, with silicone and urethane demand growing faster than other coatings.

Graphs from Webinar

Coatings are used in two ways: as roof maintenance for existing roofs or applied over newly installed roofs.

 Roof Coatings in Maintenance Applications 

There are numerous advantages to using roof coatings in maintenance applications. 

Coatings are: 

  • Often more cost-effective than re-roofing. An aging roof doesn’t always need to be replaced. Roof coatings can delay the need for replacement by extending the life of the existing roof. 
  • Less disruptive than most re-roof projects.
  • Versatile! Roof coatings can be applied over a wide variety of properly prepared substrates. 
  • Labor savers. Many roof coating projects require less labor than full roof replacements because the existing roof remains in place.
  • Energy savers. Adding a reflective roof coating over a weathered substrate lowers roof temperatures and reduces energy costs.

“Roof coatings are the most effective and least costly option to help buildings save energy,” notes the Roof Coatings Manufacturers Association


Roof Coatings in Liquid-Applied Roofing Systems 

Outside of maintenance applications, a roof coating can also be used in complete roofing systems as either a protective top coat over spray polyurethane foam, or as a reinforced or scrimmed liquid-applied membrane.  

In a spray polyurethane foam system (SPF) with a protective coating, you’re creating a monolithic insulation system that offers some of the best thermal performance available. Application is easy — the foam is self-adhering — and can be customized to fabricate pitches and correct for drainage. 

In a liquid-applied roofing system, you’re creating a monolithic waterproofing system that’s fully adhered, self-flashing, and lightweight. 

Many SPF and liquid- applied roofing systems meet UL/FM approvals​​— a testament to their quality and performance. Refer to specific Application Specifications regarding approval applicability.


Find Your Gaco System

Gaco has a long history of coating innovations. From experimentation with liquid neoprene coatings in the 1930s to providing rocket coatings to NASA in 1981, Gaco always has an eye on the future. Check out our latest product releases. Then find Gaco roof coatings near you or contact your local area manager for more information.