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How to Choose the Right Type of Coating for Your Roof

February 16, 2022 3:13 pm

A little roof leak doesn’t mean you need to spend a whole lot of money on a complete roof replacement. There’s a good chance you can repair the leak and apply a coating to renew your building’s roof for years and years to come. The same applies to a roof that’s nearing the end of its lifespan or warranty, too. But what type of coating is right for your roof? Gaco is here to help you find the right solution.

Get the answers you need in this Gaco webinar. Ed Klonowski, Gaco Product Manager, and Jason Loftus, GacoFlex Director, explain the differences between acrylic, urethane, and silicone roof coatings so you can make the best decision for your building’s location, use, and roof type.



Reach out to a local Gaco representative for more help, or request a free roof consultation today. 


Intro to Acrylic, Silicone & Urethane Coatings

While there are more than a dozen roof coatings available, just three of them make up about 85% of the U.S. coatings market: acrylic, urethane, and silicone. To understand the benefits and limitations of each roof coating, you have to first understand the basics. 

Acrylic Coatings 101

Acrylic coatings have been around since the 1950s and now make up a large portion of the coatings market. They are formulated from acrylic polymers, have elastomeric properties, and are typically white but are offered in a variety of colors to fit your needs.


Acrylic Benefits

  • Easy to clean and easy to apply, making them very user-friendly
  • Dirt resistance is inherent to the chemistry, so acrylics maintain their aesthetic appeal
  • Exceptional cost-to-performance ratio when compared to a reskin or re-roof
  • Can be applied over almost any existing low slope roofing system 


Acrylic Limitations

  • Water-soluble, so not ideal for moisture-rich environments

Gaco Acrylic Coating Solutions

Silicone Coatings 101

If you’re already familiar with silicone coatings, then you know Gaco. Gaco is a market leader in silicone roof coating systems and is responsible for the first solvent-free silicone coating. Silicone coatings are made of silicone polymers, are highly flexible, and 100% waterproof.


Silicone Benefits

  • Extended application window allows you to apply in temperatures as cold as freezing and as hot as 120℉ (compare to acrylics, with an application window in the 50℉ to 90℉ range)
  • Waterproof, so excellent resistance to moisture and won’t soften under permanent ponding water
  • UV stable and will not degrade under harsh UV rays
  • Highly reflective to help lower energy costs


Silicone Limitations

  • Tensile strength isn’t as high as some acrylics or urethanes
  • Must repair or recoat with a like-product (Silicone) 

Gaco Silicone Coating Solutions

S42 Series

GacoFlex S42

S21 Series

GacoFlex S2100



Urethane Coatings 101

Gaco first started manufacturing urethanes in the 1960s. Today, Gaco urethanes are available as single or plural component systems. The main performance attribute of urethane is its tensile strength.


Urethane Benefits

  • Single component systems are quick and easy to apply, while two component systems offer great adhesion 
  • Excellent impact and chemical resistance
  • Durable enough to stand up to extreme weather, hail, and traffic
  • Versatile applications including over metal, asphalt, and single-ply roofing systems, or over plywood and concrete as part of pedestrian and vehicular decking systems


Urethane Limitations

  • Can be a higher cost system 
  • Plural component systems involve multiple steps and components, which increases installation complexity 

Gaco Urethane Coating Solutions

Polyurethane Top Coat

GacoFlex U91

Polyurethane Top Coat

GacoFlex UA60

Is Your Roof Ready for a Coating? 


Before you can start down the path of choosing a roof coating, you have to be sure that your roof is a good candidate for one. Coatings are a maintenance solution for extending the life of an existing roof. If there’s extensive damage and too much wet insulation in your roof, it might be time for a new roof instead of a maintenance coating. Gaco can help you make this decision.


Narrow Your Coating Options by Knowing Your Building


If coatings are a viable solution, narrow your options by knowing your roof. From there, consider climate, building use and location, and the system requirements.


Building Type: What’s the Current Structure?


Does the building have a low slope roof or a steep slope roof? Is it easily seen from the ground? Does the structure need to stand up to pedestrian or vehicle traffic? What substrate material is currently on the roof? There’s a coating for each situation.  

Low slope roof: Flat or low slope roofs are prone to ponding water. Gaco Silicone roof coatings have no ponding water exclusion, which favors this roof structure.  

Steep slope roof: Steep slope roofs are designed to shed water easily. Any of the three coatings may be best for your building. 

High traffic: Durability, tensile strength and impact resistance will need to come first. Consider urethane coatings first. 

Visible roof: When a roof needs to look as good as it performs, turn to acrylics or urethanes. 

Substrate: The substrate is a layer of material that supports other roof elements. Before applying a coating, you need to know your substrate. A primer or bleed trap on the material may be needed to ensure proper system performance. 


Climate: Where’s It Located? 


A building’s geographic location is of chief importance when choosing a roof coating. Different coatings are formulated with different strengths.  

Hot, dry climates: Acrylics excel where there’s high heat and low humidity. They’re also a great way to transition a roof to a reflective surface to help save on cooling costs.  

Warm, humid climates: Silicones are perfect for tropical climates where moisture is constant. They’re waterproof and resistant to standing water. 

Extreme weather climates: Urethanes surpass acrylics and silicones with regard to tensile strength, making them ideal for areas that are prone to hail, heavy storms, and debris.


Building Use: What Do People Do in the Building?


Take into consideration the purpose of the building and how people interact in and around it. 

For example, a restaurant or food processing plant will disperse animal fats onto the roof, degrading certain coatings. Such a facility would want a silicone coating for excellent guarding against fats. Similarly, a manufacturing plant might have chemicals dispersed onto the roof. A silicone or urethane would be a great choice for chemical resistance. 

If a building needs to stay occupied during installation, picking a product with low VOCs and little disruption to daily operations should be strongly considered. 



In the meantime, continue learning about coatings by watching another webinar or visiting our Builder/Owner resource center

Make Your Coating Choice with Gaco

There’s a lot to consider when choosing the right roof coating for your building, and this webinar only grazes the surface. You don’t have to make the choice alone. Contact your local Gaco representative today for help. Our team is happy to walk your roof in person and help you better understand your warranty requirements (if any), current system service life, occupancy considerations, and installation limitations.