how do silicone roof coatings work

How Do Silicone Roof Coatings Work?

Greg PalyaSilicone Roof Coatings

Let’s say that you heard the term “silicone roof coatings” or “roof coatings” and you’re curious about what they are.

In simplest terms, contractors restore existing roofs through the installation of a coating system.

Usually, these roofs are in good condition and their warranties have recently expired. To get the roof under a new 10, 15, or 20-year warranty, some prep work needs to happen and then the silicone coating can be installed over your existing roof.

In the article, you’ll learn:

  • The installation process of a silicone roof coating system from start to finish
  • Why so many building owners are installing them
  • What roofs are good (and bad) candidates for a coating system
  • The preparation of an existing roof before the silicone coating installation
  • What warranty lengths are available
  • Is there any required maintenance on them after installation?

West Roofing Systems has been suggesting silicone roof coatings over commercial roofs as an opportunity to get a roof under a brand-new warranty, without the high cost of a full roof replacement.

Let’s get started.


What is a silicone roof coating system?

silicone roof coating system is a single layer (applied in one or two coats) of silicone that’s rolled or sprayed onto an existing roof as a liquid to fill in cracks, small blisters, and seams.
image of roof that had silicone installed on it

This process protects your existing roof system from the elements and gets your roof under a new warranty.

Silicone roof coatings are a way for building owners to get a new warranty without paying for a full roof replacement.

Why are silicone roof coating systems used so much?

Silicone roof coating systems are used for many reasons, but the two most important are cost and efficiency.


A complete roof tear off and installation of any roofing system will cost around $5 – $10 per sq. ft. (depending on many factors).

A silicone roof coating system costs between $2 – $4 per sq. ft.

This number can go up or down based on some variables, such as:

  • How much of your roof is in bad shape and will need to be removed and replaced before installation?
  • What length of warranty are you seeking? A longer warranty uses more product.
  • How large is your roof? A larger roof will cost less per sq. ft. than a smaller one.

In most cases, a silicone roof coating system is 3-4x more cost-effective than a complete roof replacement.


Compared to a full roof replacement, a silicone roof coating system can be installed much faster.

There’s less interruption to the building owner and the day-to-day activities within the building. Here are some ways silicone roof coating systems are installed quickly:

  • They don’t require the entire roof to be torn off. Only the saturated areas of a roof are torn off and replaced.
  • Silicone is fluid-applied, which makes installation around penetrations easier and more watertight than traditional systems that glue or weld boots and flashings.
  • The installation does not require many tools or equipment


What roofs are good candidates for silicone roof coating systems?

Roofs that are good candidates have:

  • Less than 25-30% of the roof’s insulation is saturated with water
  • The roof has been maintained and/or serviced at least annually over its lifetime
  • If the roof has seams, they are mostly still in-tact and the field of the roof is in good condition.

Unfortunately, some roofing issues aren’t brought to attention until water is leaking inside the building, or there are brown spots in the ceiling.

Most of these times, the majority of the roofs’ insulation is saturated with water, making the roof a bad candidate for a roof coating system.

In this situation, the best long-term solution would be a complete roof replacement.

How is a roof prepped before silicone roof coatings are installed?

Silicone roof coatings cannot simply be installed over an existing roof and call it a day. A roofing contractor follows the coating manufacturer’s requirements before silicone is ever applied to a roof.

If the correct preparation doesn’t happen, many problems will occur, such as:

  • The coating will not adhere to your existing substrate
  • The coating will not last as long as you intended it to
  • If you install coating over wet insulation, delamination and blisters can occur

It’s very important to prepare the roof properly before any silicone is installed.

Here’s what a contractor will do before installation.

The first step is to perform a visual inspection to review the overall condition of the roof. This will help determine what course of action that needs to take place.

Second, a physical inspection, multiple core sampling, and/or an infrared inspection should be performed to see if there are any saturated areas of insulation under the membrane.

After those saturated areas have been identified, removed, and replaced with like materials, the entire roof surface is power washed clean to remove any contaminants. This is usually incorporated with a wash and rinse primer.

After the roof membrane is washed, an adhesion test should be performed to determine whether a primer is required for the silicone to adhere to the roof membrane surface.

Some roof membranes will require an additional primer, but it is best to verify with manufacture recommendations or an adhesion test.

If a roof has seams, such as a Modified, TPO, or EPDM roof, there are a few steps involved with treating the seams.

Then once the seams and penetrations are treated and the entire roof is prepped, the field of the roof can receive the manufacturer’s suggested amount of coating.

How does the silicone coating get applied?

Silicone can be “spray-applied “or it can be rolled applied.

In most cases, silicone will be spray-applied because it’s faster (and more accurate with thickness) to install than rolling. If high winds are an issue, which can cause overspray concerns, then silicone will be rolled onto the roof.

It’s important when applying silicone coating to apply the right amount of coating to qualify for a contractor’s or manufacturer’s warranty.

Here are some recommended thickness requirements for each warranty length:

  • For a 10-year warranty, 20 mils of coating will be applied
  • For a 15-year warranty, 25 mils of coating will be applied
  • For a 20-year warranty, 30 mils of coating will be applied

Once the installation is complete, a contractor, third-party, or manufacturer’s representative will perform an inspection to make sure the right amount of coating was installed.

After the silicone is installed, is maintenance required?


To keep a manufacturer’s warranty active, the roof needs to be inspected at least annually.

If the newly installed roofing system is not inspected or maintained properly, the warranty can be void when a problem or issue arises.

For example, say a building owner forgets to clean out the drains or gutters for a year. The leaves stack up around drains or gutters and the water has nowhere to go. Over a year, this water has caused some performance issues within the coating system. This type of damage and repair would not be covered under warranty.

For peace of mind, it’s beneficial to let the roofing contractor that installed the coating to take care of your roof for the length of the warranty.

How long do silicone roof coatings last?

A roof that has been restored with silicone roof coatings can last as long as the building. This is because the silicone roof coating system is renewable.

Say you’d like a 10-year warranty on your roof. This will get your roof an average of 20 mils of coating.

After your 10-year warranty period, your coating thickness will degrade from 20 mils to around 7-8 mils.

NOTE: Silicone naturally wears away due to weather, foot traffic, climate change, debris, etc.

At year 10, a contractor can make any needed repairs to the roof, clean/power wash it, and install more coating up to a thickness that grants another warranty.

In the example above, a contractor can add more coating and bring the average thickness to 20 mils again, which after an inspection from the contractor or manufacturer, can get you another 10-year warranty.

The renewal process repeats itself and you get a roofing system that will last.

What are your next steps?

If you’d like to start a conversation with a silicone roof coating expert, please request a quote and we’ll contact you as soon as possible.

Want to learn more upfront?

We developed a simple, easy to understand infographic that gives you the basics of roof coating systems. All you have to do is download the “Cheat Sheet” below and it’s yours!

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.