Elastomeric coating applied on a metal roof

What is an Elastomeric Coating?

 
An elastomeric coating is a coating that’s capable of being stretched at least twice its original length (100% elongation) and recovering to its original dimensions.

Elastomerics are used in commercial roofing as a liquid that gets applied on top of an existing roofing systems to form a membrane. They also make the roof:

  • waterproof
  • a monolithic layer
  • cooler by adding an element of reflectivity from the sun
  • have an extended life
  • have a 10-20-year warranty

 
Usually an elastomeric roof coating comes in white to add reflectivity, but in some territories, such as colder climates in Ohio, a grey color can be used to absorb heat during the winter months.

At West Roofing Systems, we’ve been installing elastomeric roof coatings to restore existing roofs since 2007, including at large commercial buildings whose roofs exceed hundreds of thousands of square feet.

In this article, we’ll share what we know about elastomeric roof coatings, including benefits, different types, when it’s the best time to consider installing, and more to help you decide if an elastomeric roof coating is the right choice for your roof.
 

 

What are the three types of elastomeric coatings?

The three most popular types of elastomeric coatings are acrylic, silicone and urethane.

Acrylic – water-based coating that’s only applied to roofs with a slope. If an acrylic roof has standing water (meaning the water just sits there and does not run off the roof), the standing water will cause the reversion of the coating back to a fluid and eventually wash right off your roof.

Acrylics are typically 52% solids by volume and 48% water (or other type of carrier), so when it’s applied, almost half of the product is lost through evaporation. Although cheaper than other elastomeric coatings, you’ll need to apply much more product to account for what’s lost during evaporation.

Silicone – is a silicone resin-based coating that’s 96% solids/4% carrier. Which means 96% of what goes down on your roof will stay on your roof. Silicones perform great on flat roofs because they can withstand ponding water. Silicones are a middle-of-the-road coating in terms of performance and price.

Silicones are twice as resistant to weathering than acrylics, but also more expensive.

Urethane – urethanes have the most impact resistance of any elastomeric roof coating available. However, urethanes are very expensive compared to the other two and do not hold up to standing water very well.

What are the costs of elastomeric roof coatings?

 
The cost of an acrylic roof coating is around $14-$21 per gallon.

The cost of a silicone roof coating is around $27-$35 per gallon.

The cost of a urethane roof coating is around $40-$65 per gallon.

Type of CoatingAcrylicSiliconeUrethane
Cost per Gallon$14-$21$27-$35$40-$65

Why do building owners install elastomeric roof coatings?

 
Elastomeric roof coatings are an attractive roofing option for many reasons, such as:

  • It’s more cost-effective than completely tearing off your existing roof
  • The white color will add reflectivity which will lower energy costs
  • It’s a fast installation
  • It seals leaks and makes your roof a monolithic layer of waterproofing
  • It provides the building owner a new 10-20-year warranty
  • It’s considered maintenance and/or repair and doesn’t count as another roofing layer

 
A building can only have two roofs installed per building codes.

When should a building owner consider installing an elastomeric roof coating?

 
The best time to install an elastomeric coating over your existing roof is before your roof begins having significant performance issues.

By issues we mean small leaks, flashings showing signs of wear and tear or your rubber seams are beginning to loosen.

rubber seams loosening
 
A good example would be a rubber roof which had a 10-year warranty. Once the warranty runs out and its year 11, chances are that rubber roof is still in really good shape.

This would be a great time to install a coating because there’s probably very little, if any, moisture under the seams, and a roofing contractor can simply clean the roof, treat the seams and then install coating over the field of the roof.

By eliminating the need to remove any saturated areas of the roof, the cost of the project will be a lot lower than a few years from now when the roof is in worse condition.

NOTE: on average, a roof that has 25% or less moisture can receive an elastomeric roof coating for around $2-4 per square foot. A roof that has 25% or more moisture, it will be more cost-effective to completely tear the roof off and install a new roof, which will cost about $4-$7 per square foot.

What happens when a building owner contacts a roofing contractor about an elastomeric roof coating?

 
The first thing a roofing contractor will want to know is the history the roof:

  • Does the building have any leaks?
  • How old is the roof?
  • What roofing system is currently installed?
  • How many levels does the roof have?
  • What is the approximate square footage of the roof?

 
Once a roofing contractor knows this information, they will schedule a site visit and perform a roof inspection free of charge.

One way a roofing contractor can tell if there’s any saturation in the roof is by noticing a bungee or soft presence when walking the roof.

Another way is through an infrared survey.

After the inspection, there will be a caveat in the proposal that states that after an infrared survey has been performed, those areas will be removed and replaced with matching materials before the elastomeric coating can be applied.

NOTE: For proper adhesion and performance, coating should NEVER, NEVER, NEVER be installed over saturated insulation or substrates.

A roofing contractor will explain their findings of the infrared survey and give the building owner options (and recommendations) to choose from.

Where can you get an elastomeric roof coating on your building?

 
At West Roofing Systems, we’ve installed coatings over existing roofs everywhere East of the Mississippi.

If you’d like us to contact you, please fill out our form and we’ll contact you within 48 hours (but most likely within 10 minutes because I get form notifications 😊)

If you’re not ready to talk to a roofing contractor, no biggie! Download our free eBook to learn more about our most popular coating application, the silicone restoration membrane:

Download our free guide to silicone restoration membranes

Author: Greg Palya

Greg Palya is the Digital Content Manager of West Roofing Systems, Inc. He has a B.S. in Marketing from the University of Akron and an MBA in Marketing from Walsh University. When he’s not trying to increase website traffic, you can find him on the basketball court or golf course.

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