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Roofing Resources

Sealing a Roof with a Roof Coating

Whether you have just installed a new roof or are trying to extend the life of your existing one, roof coatings are a hot topic in the home improvement market these days. The growing trend is largely attributed to an increasing desire among homeowners to be more environmentally conscious while also reducing energy costs. Typically, the average lifespan of a roof is about 25 years without a full replacement. However, exposure to severe weather can provide wear and tear. Here’s what you need to know about sealing your roof with a coating, and whether or not it is worth the investment.

Table of Contents

What Does Sealing a Roof Mean? 

Roof sealants are added to your roof to extend its life expectancy. Sealing a roof provides an extra layer of protective coating that can help prolong damage from extreme climates and other hazards, including sun, rain and ice. The idea is to let the roof coating take a beating, instead of a roof’s tiles or shingles.

Roof coatings are especially useful for roof types that collect water and debris, such as flat roofs. They can also be used on other angled roof types as they age to protect from long term damage. Roof sealants can make your roof a little more fire-resistant, and prevent the growth of mold and algae.

Roof sealants and coatings need to be applied by experienced, professional roof contractors. For instance, a novice roofer may leave pinhole-sized openings in the coating which, believe it or not, are often enough to cause leaks and other issues. So, in a word, hiring a quality roof installer is vital.

sealing a roof

Types of Roof Coatings

The coating consists of elastic-type properties and looks like a thick sort of film. The flexibility within the sealant is purposeful. It provides extra give to extend and retract when roof a roof is exposed to extreme weather conditions.

The most common roof coatings are made of the following materials: 

  • Polyurethane
  • Silicone
  • Acrylic
  • Liquid rubber

Factors that go into choosing the best type of roof coating material depend on the region you live in and surrounding climate, material costs, and the ease of application.

How Much Does it Cost to Seal a Roof?

The cost to apply a roof coating will depend on the size of the roof and the materials chosen.

On average, homeowners pay about $1,000 for a roof coating. The cost varies, but typically roof coating prices range from $1.00 to $3.00 per square foot before labor.

Here’s a look at the average price for roof coatings depending on the materials selected:

Roof coating costs
Coating materialAverage cost
Polyurethane$1.50 to $4 per square foot
Silicone$1 to $3.50 per square foot
Acrylic$0.15 to $2.50 per square foot
Liquid rubber$1.30 to $2 per square foot

Sealing a Flat Roof

If you have a flat roof on your home, you probably already know a little bit about waterproofing. Sealing a flat roof is absolutely necessary. Flat roofs are designed kind of like big swimming pools with drainage systems that carry water off the surface and down onto the ground. For this reason, they need to be entirely sealed. Even the tiniest crack can let water into your underlayment and, eventually, spring a leak in your home.

Benefits of Applying Roof Coatings

Simply put, a roof coating helps your roof last longer. That’s because you are opting to add an extra layer of protection that can take a beating from the weather and extreme elements over tiles or shingles. Explore the various benefits of sealing your roof with a coating below.

Roof sealants serve as a waterproof coating over a number of different roof surfaces. Elastomeric (i.e. rubber) and silicone roof sealants form a protective seal over your roof. The best kinds will be breathable as well, to allow moisture from household activities—like cooking and showering—to escape through your roof. Many manufacturers claim using their products can extend your roof’s life by several years or more.
UV Protection
Sitting out in the sun all day long can be tough on your roof—particularly if you have asphalt shingles. Ultraviolet rays cause molecular changes in the shingles, and eventually, that leads to curling and degradation. Some roofing materials contain reflective materials to limit this problem. But another way to do it is with a good roof coating. Reflective elastomeric roof coatings can prevent UV damage, according to some roofing professionals.
Increased Fire Resistance
In some cases, roof sealants can also act as fire-retardants for your roof. Of course, if you’re really concerned about your roof’s fire rating, installing a metal roof is probably the best way to go.
Mold Prevention
Rubber roof coatings have a fairly low permeability, which means they don’t stay moist—or allow harmful microorganisms like mold and algae to flourish. That’s a boon if you live in a damp area where mold threats are high.
Reduced cooling costs
The reflective qualities of roof coatings drop a roof’s temperature and slow UV ray’s lasting impacts. In turn, a home’s air conditioning system will be less strained.
Easy to apply
Roof coatings also come with the advantage of easy installation. While it’s important to hire a trusted contractor, the process is fast and not too intensive or noisy. While the length of time it takes to complete a roof coating pends on the size of the roof, typically, from start to finish, the task takes up to two days. The most important thing is to pick a professional who knows how to properly apply a roof coating.

Do Roof Coatings Work?

Roof coatings are able to increase a roof’s lifespan and can help reduce energy usage. But, it’s important to note that if something sounds too good to be true, it probably is.

What we mean to say is roof coatings can get a bad rap because of too-good-to-be-true oversells boasting false claims about a roof coating’s benefits.

If a roof coating company boasts pie-in-the-sky claims — like that your HVAC bills will be slashed in half because of a sealant — something is wrong. In fact, representatives from a roof coating company in the UK were charged with five years in jail for fraud—courts found that they falsely claimed their sealing products would reduce heat loss by 25 percent.

That’s not to say roof coatings will not come with protections that make your home more efficient. But it is very important to discuss real expectations with a trusted contractor before committing to a particular roof coating. Make sure you understand what roof sealants are good for and the actual benefits that your roof coating will provide you.

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