What’s Up With Roof Coatings?

by Katie Lee

The truth about roofing’s most controversial “system.”

By Page Wright

Depending on who you ask, liquid-applied roof coatings are either a plague that gets slopped on top of a perfectly good roof, or it’s the future of roofing systems. Like with most things in life, between the extremes, you will find the truth. With that in mind, let’s cut through all the claims and accusations to determine if roof coatings are a viable option for the stores or restaurants you manage.

What are Roof Coatings?

Before we do a deep dive into the pros and cons of coating your roof, let’s establish a clear, industry-approved definition for roof coatings. According to the Roof Coatings Manufacturers Association (RCMA): “Roof coatings are designed for protecting and extending the useful service life of roof assemblies for new construction and more commonly, existing roof coverings, such as BUR, metal, modified bitumen, single ply membranes, and spray polyurethane foam.” Additionally, there are many viable types of coatings to choose from including acrylic, silicone, polyurethane and asphalt coatings.

primary waterproofing layer 1While it’s tempting to think roof coatings are the same as exterior paint, nothing could be further from the truth. Just ask any roofing contractor who’s run into a roof that was “patched” with a glob of paint and they’ll tell you paint never holds up to the sun’s UV rays and fails under constant exposure to the elements.

What makes roof coatings so resilient? Unlike exterior paint, roof coatings are specially formulated to be thicker and more elastic. The resins and polymers within the coating provide higher elasticity. This elasticity allows the material to maintain its structural integrity as it expands and contracts due to the changing weather.

Now that you know some basic facts about liquid-applied roof coatings basic, let’s consider some of their benefits as well as some critical things to look out for.

Roof Coatings Benefits:

  • Extended Protection: When applied correctly by a professional, coatings can provide a waterproof barrier that seals the surface of your roof. When the proper number of coats are applied over an existing membrane, the overall system’s efficiency is enhanced thanks to a reduction in thermal expansion and contraction. Retail and restaurant building owners who choose coatings also save money while extending the life of their roof 10 years or more.
  • Fewer Leaks = Fewer Service Calls: A properly coated roof will experience fewer leaks and, as a result, fewer maintenance issues both inside and outside of your stores or restaurants.
  • Increased Energy Efficiency: There’s a simple reason why white is the most common color for roof coatings. Properly coated white roofs experience reduced thermal transfer since they continuously reflect the sun’s intense ultraviolet rays away from the roof. That enhanced reflectivity reduces the strain of heavy usage that typically happens to your facility’s HVAC units, thereby saving you money on utility bills as well as prolonging the life of the units themselves.
  • Quick Installation: Roof coatings can be applied quickly, which means you won’t have large crews on top of your facility for an extended period. The best, most efficient crews are on and off your roof quickly.
  • secondary protective layer 2ASTM Sustainability Standards, Energy Star & LEED Credits: When you consider the increased energy-efficiency and the savings, being able to add Energy Star rating or LEED credits to your facility is an added-extra bonus. In addition, roof coatings contribute toward ASTM sustainability standards and other energy code requirements.
  • Structural Benefits: Roof coatings do not pile on dead weight to your building’s existing roof, which means there is little-to-no detrimental effect to the overall structure.
  • Cost Savings: Applying coatings usually requires less labor, fewer materials, and fewer disruptions and/or downtime for your facility. Also, because they don’t require a tear-off, the cost of associated with coating your store or restaurant’s roof can be significantly less when compared to the cost of a standard roofing systems replacement or recovery project.
  • Warranties: Many coating manufacturers offer excellent warranties on their products (generally around 10 years). Of course, as with all contracts, it’s highly recommended that you carefully review the terms of any warranty to ensure it suits your and your building’s needs.
  • Tax Incentives: One of the largest, most talked about benefits of coatings is how they can be listed as an operating/maintenance expense on your taxes. Consult with your tax attorney to gauge any possible tax benefits since the location of your stores or restaurants could factor into whether or not you receive this benefit at all.

Roof Coatings Factors Too Crucial to Ignore

Before you stop reading this article and call some random local roofer to brush some coatings on, let’s take a breath and peek under the membrane. Why?

Remember, it’s restoration, not resurrection! Restoring your roof with a professionally applied acrylic or silicone coating has its place. Anyone who tells you it’s a surefire cure-all without doing the proper inspections is setting you and your building up for failure.

Do you own the building? Well, that also means you own the existing deck and substrate that’s underneath your existing membrane. Remember…

The Building Code Always Applies!

For many states and municipalities, there are local building codes that must not be circumvented or ignored. Therefore, it’s imperative that you fully understand your current roofing system. Ignorance is never a viable defense and you don’t want to pay a hefty fine for non-compliance. To protect yourself, here are two critical questions you need your roofer to answer:

1. How many layers of roofing are currently installed on the building? If the roof has one layer of BUR or TPO, then the code allows you to add a second layer. However…

The IBC (International Building Code) requires a full roof tear off if two or more roofs are in place. Therefore, adding a third layer of roofing is prohibited except when it comes to coatings which are often not considered a third roof. This is where having a professional roofing contractor on your side is paramount since they will know they need to consult with your local building code official. Your local code official will make the final call and require you to do a full tear off or give you permission to apply coatings over a building with two roofs. NOTE: If any contractor tells you, “We don’t have to consult with anyone! We’ll just remove the top layer and apply the coating on top of the first layer” run, don’t walk, away from that project! Why?

If you must remove any layer, you must also remove all layers (membrane, ISO, etc.) to the deck. The code does not allow you to tear off the top layer and then apply a coating.

2. What’s the condition of my roof underneath the membrane? Make sure your roof is properly inspected to ensure the existing substrate and/or insulation is in good shape before that first drop of coatings is applied. Also, areas where water enters and any failed or failing surfaces must be properly remediated prior to applying the coating.

Separating the Pros from the Cons

Remember the two benefits of quick installation and cost savings from before? Well, shady applicators who may or may not have any commercial roofing experience have no problem exploiting those two benefits to their advantage. By preying on your inexperience, they can get in, get out and then leave you with a suspect roof without your knowledge.

A professional roofer will not waste your time spewing claim after claim. They will take the time to get to know you and, more importantly, every inch of your roof. Once a thorough assessment of your roof is complete, they will share with you their recommendations for which coating works best. Best of all, they will already know how many coats your roof will need and how to apply it. For instance, an experienced contractor will not have to consult a manual to know that two coats are recommended for acrylic coatings. How can you be sure you are working with a seasoned pro?

Here are three questions you can ask to ensure you choose a professional commercial roofing contractor you can trust:

  1. “What’s the status of my roof?” If the people you’re considering can’t conduct the proper imaging scans, let alone do a core test, then it’s time to find a new roofer.
  1. “What kind of equipment do you use?” Besides having a level of competency with the materials themselves, choosing a contractor who uses the right equipment to apply the coating is also a good idea. Gas-powered sprayers and air-assisted sprayers help provide an even coat, but they’re only as good as the person operating them. Which leads to our final question…
  1. How will you ensure this project qualifies for the manufacturer’s best warranty?” The last thing you want to hear after the manufacturer’s inspection is that your roofer failed to apply the coatings correctly and that your project is ineligible from receiving a 10-year warranty. If, during the manufacturer’s final inspection, they discover the wrong number of coats where applied, or they were applied using the wrong application pattern, your chances of getting the best warranty just vanished. Each manufacturer’s different and can require different methods depending on the type of coating you choose. A reliable and respected roofing contractor will know the differences and guide you and their crew to the best result.

Ultimately, your roof is your most important asset. Due to age and environmental factors, leaks and other issues are bound to happen to every building. Roof coatings can help extend the life of existing roofs, but only under the right circumstances. If your roof is filled with moisture, or at the end of its serviceable life, applying a roof coating could very well be a huge waste of money. However, if you find the right roofer and have a well-maintained roof that gets routine preventative maintenance, then applying a roof coating could very well be a huge money saving opportunity.


— Page Wright is a service manager, NACE Coating Inspector Level 2 Certified, with North American Roofing. As service manager for North American Roofing, Wright uses his wisdom about single-ply roofing systems and coatings to serve retail and restaurant facility managers and property owners across the country.

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