How Long Do Elastomeric Roof Coatings Last?
Do you have a commercial roof that needs to be restored? Perhaps your warranty ran out but your roof is still in good condition?
Did you know you can add an elastomeric roof coating over your existing roof to extend its life?
But for how long?
Elastomeric roof coatings can last between 10 and 20 years.
This all depends on the millage of coating that’s applied to your roof.
A 10-year warranty requires 20 mils of coating.
A 20-year warranty requires 30 mils of coating.
At West Roofing Systems, we’ve been extending the life of well-conditioned roofs through elastomeric roof coatings since 2007 (roofing in general since 1979).
Therefore eliminating the need to completely tear off a roof (and adding to landfills), but to extend the life of the roof, add in reflectivity (save on energy costs) and create a seamless, watertight layer with a new 10-20 year warranty.
A quick recap of what an elastomeric roof coating is
An elastomeric roof coating is a fluid applied coating that’s sprayed or back-rolled directly onto an existing roof system.
Usually, these roofs are in good working order with minimal leaks, and their warranty is about to expire.
A building owner installs an elastomeric roof coating for a few reasons:
- it’s more cost-effective than a complete tear-off
- it’s considered maintenance (is not considered another roof layer)
- it adds a seamless, monolithic waterproof layer
- it’s white, therefore it saves on energy costs compared to a dark-colored roof
But how long do elastomeric roof coatings last?
Elastomeric roof coatings will perform for 10-20 years depending on the initial application thickness.
For a 10-year warranty, 20 mils of elastomeric roof coating will need to be applied.
For a 20-year warranty, 30 mils of elastomeric roof coating will need to be applied.
The elastomeric manufacturer (Henry, Progressive Materials, etc.) have performed extensive weather testing to determine how long their products will last.
Can elastomeric roof coatings last longer than their warranty?
Yes, and most of them do. It isn’t extraordinary to see a 10-year warrantied roof still be in great condition after the warranty has expired.
Brian Chavalia (30+ years of commercial roofing experience at West Roofing Systems), has seen this personally. He has inspected a roof 15 years after restoration and saw that the topcoat still had all the granules embedded.
If the granules are still embedded, all that coating is still underneath, otherwise, the granules would be gone.
An important fact to note is elastomeric roof coatings will last longer with proper annual maintenance and inspection of the roof, especially after weather impacting events, such as bad thunderstorms and hail storms.
What maintenance is done to extend how long elastomeric roof coatings last?
Most roofing maintenance programs begin with a visual inspection and reporting. They are looking for early signs of significant damage. Damage can be caused by numerous events such as wind, rain, debris, or any foot traffic having access to the roof.
Maintenance also includes special attention to areas that impact water travel, such as gutters, drains, and scuppers. A roofing contractor wants to make sure that when it rains, that water is moving the way it’s designed to off the roof.
NOTE: A maintenance contract is a great way to keep your facility in good shape while holding your contractor accountable for the performance of their work.
Has an elastomeric coating ever NOT lasted it’s intended lifetime?
No. And if it ever didn’t last as long as it was intended too, it would’ve been applicator error. Some forms of applicator error would be:
1) Coating too thinly
For a 10-year warranty, 20 mils of coating needs to be applied. If less than 20 mils of coating is applied, then the product may not last the entire 10 years.
2) Coating too thick
If the coating is applied too thick (more than 20 mils for a 10-year warranty), then it’s simply shame on the roofing contractor and great for the customer. This roof will perform great for more than 10 years.
3) Mixing improperly
The coatings that are used now are single component, meaning you just pop the drum open, give it a swirl and begin putting the product down. However, older coatings may have multiple components that need to be mixed to perform properly. If not, then the product is not going to perform how it was designed to perform.
4) Applying before a rainstorm
This one depends on the type of elastomeric coating the roofing contractor is applying. If it’s silicone, then it doesn’t matter. Silicone will still perform as it should if it rains slightly after installation. However, if the roofing contractor is applying acrylic or urethane coating, rainfall slightly after installation will damage that coating. Rain can even wash your coating off the roof!
5) Poor substrate preparation
Preparation is King!
Just like painting the walls of your home, if your walls are full of dirt or dust, the paint isn’t going to adhere or perform how it should. A roofing contractor needs to clean and dry your existing substrate before application. If this isn’t done, the coating will not adhere properly and will not perform how it was meant to.
A rule of thumb is clean, dry, and sound.
The roof should be so clean that if you drop your sandwich, you should still want to eat it.
A very clean roof is important for proper adhesion and performance.
Does High Solids Silicone last longer than solvent-based silicone?
Newer to the industry than traditional solvent-based silicone is what’s called High Solids Silicone.
Without getting too technical into what the differences are between them, roofing contractors are noticing the high solids showing fewer signs of deterioration that the solvent-based silicone does.
Some tendencies include an increased rate of wear and chalking.
Roofing contractors are using high solids more and more every day. At West Roofing Systems, we are at an approximate rate of 90% high solids/10% solvent-based.
Why is solvent-based silicone still used?
On a roofing re-coat (say you did a silicone coating over your roof 10 years ago), a roofing contractor will most likely use a solvent-based coating. The reason is that solvent-based silicone grabs onto existing silicone better than high-solids silicone.
While high-solids silicone adheres to spray foam and rubber tremendously, it doesn’t grab onto existing silicone as great as solvent-based does.
First time coating application = high-solids silicone, Re-coat over a high-solids silicone will most likely be high-solids.
Re-coats over a solvent-based silicone roof = solvent-based coating.
NOTE: Before installing coating over an entire roof, an adhesion test will be performed to make sure that type of coating adheres properly.
Summary of roof coatings and how long they last
Elastomeric roof coatings last 10-20 years.
Typical maintenance that’s done on elastomeric roofs are:
- visual inspections meant to notice signs of significant damage
- to fix minor repairs
- to clean debris away from waterways so the water streams the way it’s designed to off your roof
Roofing contractors are beginning to use a “high solids” type of silicone for roofing purposes. The first time we put high solids down was in 2007, probably about the same time other roofing contractors were doing the same thing.
There are no studies out there that provide evidence high solids silicone is a better roofing product than solvent-based silicone.
However, high solids are showing no signs of the typical tendencies solvent-based silicones are showing, like extensive wear and chalkiness.
Below is a free guide about Silicone Roof Coatings where you can quickly learn about:
- How much do silicone roof coatings costs?
- What problems they have?
- What benefits do they have?
And much more!
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.