How To Get 10 More Years Out of an Old, Metal Roof?

Greg PalyaSilicone Roof Coatings

Summary: To extend the roof life of an existing metal roof, you can install a roof coating system. A roof coating system involves minor repairs, seam reinforcement, and the application of a thick, elastomeric coating that’s engineered specifically for metal roofs. If you install the system correctly, you can get a new 10-20-year warranty.

So, you got an older metal roof that probably has some leaking, and you probably want to know what repair options you have.

You know one option is to call a metal roofing company, who will rip everything off and install a new metal roof.

But maybe you’re wondering if there are other more cost-effective options.

I’m here to tell you that there is!

I’d like to introduce you to a roof coating system, silicone restoration membrane, elastomeric roof coating system…there are many names in the industry.

But they are all the same. They make minor repairs, they reinforce the seams on your metal roof, and then they install a super thick paint-like coating that’s engineered for metal roofs.

Then you get a new 10-20-year warranty.

I know it sounds simple, and it is, but I’m sure there are other questions you might have, such as:

  • How much does a coating system cost versus a metal roof replacement?
  • Is my roof in good enough condition to be coated?
  • What is the start-to-finish process for installing a coating system?
  • What happens once the coating wears away?
roof coating system over an existing metal roof

We’ll answer all these questions below.

We wanted to let you know that every piece of content written at West Roofing Systems is produced in-house. It’s also reviewed, edited, and approved by a spray foam/coating expert with more than 30 years in the field.

West Roofing Systems has been in commercial roofing since 1979.

Now let’s get started!

How much does a coating system cost versus a metal roof replacement?

This is very tricky to answer accurately.

If you would ask me this question in the summer of 2021, I’d tell you that a full metal replacement would be around $10 per square foot, and a roof coating system would be around $3 per square foot.

However, with labor and product shortages, as well as logistic problems, the price is much higher than before.

Right now (December 2021) it’s a very volatile market with commercial roofing products where the prices change daily.

Here are some other things to consider when looking at costs:

  • The distance your roof is away from the metal roof contractor, or the coating contractor will factor into the price.
  • If you go the coating route, the amount of rusted or damaged metal that needs to be removed and replaced will factor into the cost.
  • For coating, you can choose a 10, 15, or 20-year warranty. The longer the warranty, the more coating will be used. This can drive the cost up or down depending on which length of warranty you choose.

Now that understand pricing a little, you might be wondering “is my metal roof in good enough condition to be coated?”

Is your metal roof in good enough condition to be coated?

Three factors determine if your metal roof can be restored with coating or not:

  • Are the seams in good/decent condition?
  • Is less than 25% of the roof’s panels deteriorated or the underlying insulation saturated?
  • Has the roof been maintained (or serviced) at least annually?

If the answer to any of these is NO, your roof is probably in too poor of a condition to be restored with coating.

Your best option may be to remove all the metal panels and start over. If you’d like us to take a look at your roof, please fill out a request a quote form and we’ll get right on it!

Let’s say that your metal roof is in good condition and it’s eligible to be coated, you might be wondering “what is the start-to-finish process on how this all works?”

What is the start-to-finish process for installing a coating system?

The first step to installation is to remove all the surface contaminants that can interfere with the coating’s proper adhesion. This is done through power washing at a minimum of 2500 PSI.

A rinseable cleaner wash may be used in tandem with power washing.

Next, the entire roof may be primed with a manufacturer’s suggested type of metal primer.

The next step is to reinforce the seams. This is done by installing a heavy coat of silicone over the seams (usually 12 inches wide), then embedding a polyester mesh into the wet coating, then encapsulating the mesh with another heavy coat of the coating, and letting the area dry overnight.

Then the base coat of coating is applied over the entire roof. Then the topcoat is applied.

  • For a 10-year warranty, the roof will receive a thickness level of 20 mils of coating.
  • For a 15-year warranty, the roof will receive a thickness level of 25 mils of coating.
  • For a 20-year warranty, the roof will receive a thickness level of 30 mils of coating.

So, if you’re trying to get 10 more years out of your metal roof, a coating thickness of 20 mils will get you there.

You might be wondering, “What happens in year 10? Will I now have to rip all the metal off?”

What happens once the coating’s warranty expires?

In year 1, you’ll have 20 mils of coating.

In year 10, you’ll likely have 7-8 mils of coating left.

What makes coating systems attractive for long-term cost-effectiveness is that they are renewable.

In year 10, minor repairs will be made (if any), the roof will be power-washed clean, and then a contractor will bring the 7-8 mils up to 20 mils.

A new 10-year warranty would be granted.


Now that you know what coating systems are and how they can extend the life of your metal roof, what other concerns might you have?


And if you’re brand new to roof coating systems, please check out our cheat sheet below!

download the silicone roof coating cheat sheet
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.