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How to Get an Existing Commercial Roof Under New Warranty?

Greg PalyaSilicone Roof Coatings

Short answer: Install a roof coating system. Doing so can get you a brand new, renewable, 10-20-year warranty.

So, you manage a commercial roof and notice that your warranty is about to expire.

Now, what do you do?

You can call the contractor that installed it and see what they say?

Hopefully they are still around. And hopefully they offer you a cost-effective option to keep your warranty going.

If they propose a complete tear-off…beware!

You may be able to simply add a roof coating system over your existing roof, avoiding the complete tear-off.

In this article, you’ll learn:

  • Why would you want a new warranty? 
  • Should you get a new warranty if there’s no leaking?
  • How long of a warranty can you get?
  • Are all roofing systems eligible to be coated?
  • What is an example scope of work for a coating system?
  • What is the ballpark cost for a coating system?

And just so you’re aware, West Roofing Systems has been in commercial roofing since 1979. We specialize in spray foam and roof coating systems. We often get asked questions about getting commercial roofs under warranty, renewing warranties, etc.

This article has been read, edited, and approved for publishing by one of our commercial roofing experts with more than 30 years of experience.

Let’s get started!

silicone roof coating system over an existing metal roof

Why would you want a new warranty?

Most property managers want the roof under a new warranty because if something happens with the roof, they aren’t financially responsible for the repairs.

It’s also a peace-of-mind thing.

If something happens with the roof, I know who to call. I won’t have to scramble trying to find a contractor I can trust.

It’s also a safety thing.

If there are roof issues, I won’t have to send one of my workers up there; which is a huge safety risk.

Should you get a new warranty if there’s no leaking?

If you have a warranty about to expire, the roof will likely begin to breakdown shortly after the warranty is over.

Roofing material manufacturers know what they are doing and have extensive testing on how long materials last under certain conditions.

For example, let’s say you have a TPO roof with a 15-year warranty. The TPO manufacturer is probably 99.9% sure that roof will last 15 years if it’s installed and maintained correctly.

After year 15, the membrane may begin to dry out and crack. The seams might lose adhesion. The adhesive used to watertight the TPO around penetrations might start to lose performance. And so on, and so on.

What you don’t want to do is let the warranty run out, ignore the roof since it’s out-of-sight, out-of-mind, the insulation becomes wet, it eventually leaks, and now the roof is in such poor condition, you must tear it all off.


How long of a warranty can you get?

For a roof coating system, the most common range is 10-20 years. The warranty length for a coating system is always determined by the thickness of the coating.

For example:

  • For a 10-year warranty, 20 mils of coating is installed.
  • For a 15-year warranty, 25 mils of coating is installed.
  • For a 20-year warranty, 30 mils of coating is installed.

Are all roofing systems eligible to be coated?


There are two issues: the existing roof system and the condition of it.

The existing roof system

All existing roof systems can be coated. If you have a gravel-built-up roof or any unsmooth roofing surface, installing a coating system may not be cost-effective.

The reason is that it may require a very large amount of coating to smooth the roof out.

Installing a spray foam roof may be more cost-effective.

The existing condition

There are three main checkpoints used to determine if your roof is eligible for a roof coating system:

  1. Is less than 25% of the roof’s insulation wet?
  2. Do the seams have decent/good adhesion?
  3. Has there been annual maintenance?

If your roof fails any of these points, you can still get a new warranty for your existing roof; it just wouldn’t be through a roof coating system. You might have to do some tear-off and install another roofing system, such as TPO, Spray foam, or Metal.

St. Mary's Church - Silicone Coating over EPDM - Wakeman, OH - 2021.JPG

What is an example scope of work for a coating system?

  • Pre-job inspection
  • Adhesion test
  • Moisture scan
  • Setup warning lines/flags
  • Remove all surface contaminants via power washing at a minimum 2500 PSI (use cleaner if required by manufacturer)
  • Prime the roof as required based on adhesion testing
  • Any areas that aren’t secure to the membrane will be fastened down
  • Any fasteners, screws, or plates will be sealed with coating
  • Install a primer (if needed)
  • All seams are reinforced (with seam tape or mesh) and/or with coating
  • All rooftop equipment to be masked
  • Apply basecoat of coating (at manufacturer’s specs to achieve warranty)
  • Apply topcoat of coating (same as above)
  • Remove all job-related debris, surplus materials, and leave the premises in a neat and orderly condition
  • Issue warranty

What is the ballpark cost for a coating system?

The ballpark cost for a coating system installed on a commercial roof is $3 – $7 per square foot.

Many variables influence price, such as:

Desired warranty length

A warranty for a coating system is always determined by the thickness of the coating installed. More coating = more cost = longer warranty.

Roof preparation

Is there any damaged decking that needs removed and replaced? Is there any wet insulation that needs removed and replaced?

Distance from roofing contractor

Gas to and from the job, labor hours driving, flights, and hotel stays contribute to job cost. However, you never want to choose a roofing contractor based solely on location.

The most important part of a successful roofing installation is the quality.

If a contractor is 2-3 states over, and you’re confident they will install a quality roof, so be it.

It’s a lot better to pay a little more for a contractor faraway then have a sub-par installation, your roof leaks, and they are no where to be found.

EPDM roof renewed with silicone coating


Hopefully, you now know about roof coating systems and how they can get a commercial roof under a new warranty.

Here are other articles you might find helpful:

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About the 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 teach others about spray foam roofing and silicone roof coatings, you can find him on the basketball court or golf course.