What is Spray Foam Roofing?

spraying foam on roof

Whenever you imagine a new roof installation, chances are you probably don’t envision someone spraying a new roof right on top of your house. But that is exactly what spray foam roofing is: a spray-on roofing system. 

Spray foam roofing isn’t the most well-known or conventional roofing material. In fact, some have never heard of it. But if you’re in the market for a roof replacement, SPF roofing is an option to consider, as spray foam roofs are easy to install and have several benefits. 

So what is spray foam roofing, and what are the advantages and disadvantages of this unique roofing material? 

In this article, we’ll cover:

What is Spray Foam Roofing?

Spray polyurethane foam roofing, more commonly called spray foam roofing, is a spray-on roof that is a great option for those seeking a waterproof or well-insulated roofing material. 

It is applied to a roof as a liquid before the foam hardens and becomes solid. Because spray foam roofing is a fluid when applied to a roof, it has a natural adhesion and does not require fasteners to secure it to the roof deck. 

While some might think that spray foam roofing is a new discovery, spray foam roofing has been around since the 1960s. It has been used for industrial, residential, and commercial roofing. 

Spray foam roofing is an easy roofing option that offers a lot of benefits. Not only is it cheap, but it adds durability, insulation, strength, and protection to your roof. 

Closed-Cell

Spray foam roofing comes in two types of polyurethane foam: open-cell and closed-cell. 

SPF roofs are made of closed-cell spray foam, making them water resistant and durable. Closed-cell spray foam is a rigid, hard material that has a high R-value, which means it is well insulated. 

Open-Cell

Typically, open-cell spray foam is used for insulating attics and other interior areas. Open-cell foam is not waterproof, but it is malleable and flexible.

How is Spray Foam Roofing Installed?

The installation process for spray polyurethane foam roofing systems is easier and quicker than traditional types of roofing.

Before a spray foam roof is installed, the substrate roof beneath first needs to be cleaned of dirt and debris. 

The process to install a spray foam roof is simple:

  1. A spray foam roof is applied directly to the roof in liquid form. The foam is created when isocyanate and polyol resin are combined and then sprayed directly onto an existing roof through a heated hose.
  2. Once it has been sprayed on the entire roof, the liquid expands to a foam that is 20-60 times its original size. 
  3. After expanding, the foam hardens into a solid protective coating over the roof. The layer of spray foam applied should be about 1.5 inches thick. 
  4. Finally, an elastomeric coating is applied. This protective layer, most commonly silicone, protects the spray foam roof from damaging UV rays and lowers heat absorption. This protective coating is usually about 25 to 30 mils thick when dry. 

Because of the unique chemical reaction it takes to install a spray foam roof, it must be applied under certain weather conditions. The outside temperature needs to be at least 50 degrees F. The foam will not install properly if the temperature is too cold. 

No need to worry about rooftop features such as skylights, HVAC units, chimneys, or vents, as a spray foam roofing application can easily be sprayed around such objects.

What Roofing Materials Can SPF Roofing Be Applied to?

A spray foam roof can be sprayed onto any type of roof. It works especially well on roofing materials designed for flat or low-sloped roofs such as:

  • Built-Up Roof: Built-up roofs consist of alternating layers of asphalt and ply sheets topped with a layer of stone, gravel, or similar aggregate.
  • EPDM Roofs: EPDM roofing is a durable synthetic rubber membrane.
  • Metal Roofs: Metal roofs can be made of aluminum, copper, steel, tin, or zinc. 
  • Modified Bitumen: Considered a cousin of the built-up roof, modified bitumen is a roofing material made of asphalt and polymerized rubber.
  • TPO Roofs: TPO roofing is a single-ply rubber roofing material. Typically, TPO roofs are applied to commercial buildings.

The spray foam applied fits over any style roof, no matter how irregularly shaped the roof is. Because of the way spray foam roofing expands and conforms to the substrate the foam is applied to, they are a great option for flat roofs or sloped roofs. They can fit over any roof deck, no matter how unusual or unorthodox the shape. 

What is the Cost of Spray Foam Roofing?

The expense of installing a spray foam roofing system varies depending on various factors such as foam thickness, spray foam type and quality, size of the roof, amount of prep work, the existing roof’s condition, and the UV coating. 

In general, the price of a spray foam roof installation can cost anywhere from $3 to $12 per square foot

Pros of Spray Foam Roofing

Lifespan

At the end of its warranty, SPF roofing can be renewed by applying another elastomeric coating over your roof to keep a strong UV barrier protecting the roof. A spray foam roof should be recoated about every 5 to 10 years.

With proper maintenance and regular recoatings every few years, a spray foam roof can last up to 50 years. If the roof needs to be replaced or is damaged, it can be removed, primed, and then the roof can be re-foamed and re-coated with a new spray foam roof. 

Weather Resistance

A spray foam roof is a seamless, cohesive layer protecting your roof, making it a waterproof roofing material resistant to leaks. With traditional roofing materials, seams and crevices are usually where roofs suffer leaks. But with spray foam roofing, there are no seams for the water to drip through, making them watertight. 

Known to hold up in any climate, spray foam roofs are durable roofs that protect against extreme weather conditions such as hail, rain, high winds, and snow. Because they are a seamless rooftop layer, they don’t lose shingles to wind uplift like other types of roofs do. 

Installation

Since installing a spray foam roof is easy, it takes less manpower for the job. Fewer roofers are needed to apply the coating to your roof, which can save money on labor costs

Additionally, you don’t have to tear off the old panels to install a spray foam roof, which makes the installation process easier, faster, and cheaper. 

Maintenance

Spray foam roofs are easy to repair and maintain, although just like any other roofing system, a spray foam roofing system requires regular maintenance. Spray foam roofs need to be regularly checked for damage such as cracks, splits, blisters, punctures, and holes. 

If a spray foam roof develops a small crack or hole, it can be easily fixed by filling it in with caulk and smoothing it over. They are resistant to mold and mildew. 

An SPF roof must be kept debris-free such as sticks, leaves, and bird nests. Sweeping the roof with a soft broom when needed should be enough to keep your roof clear of debris. The gutter system needs to be unclogged to prevent ponding water on your roof. 

You will want to keep an eye out for discoloration of your roof surface. Stains or discoloration indicate a roofing problem that demands attention. 

The roof’s texture is important to keep an eye on, as well. The texture of a spray foam roof’s surface should be consistent throughout the entire roof. SPF roofing usually has a texture like an orange peel. 

Self-Flashing

SPF roofs are a monolithic material that conforms perfectly to the roof it’s sprayed on, making them self-flashing. Self-flashing means that roofing shingles don’t need to be secured to the roof decking with fasteners or adhesives. 

Price

Spray foam roofing offers a cheap, cost-effective option. Instead of paying the expenses for a roof replacement, you can reinforce your existing roof with a protective spray foam coating. That saves on the cost of having to tear off the old roof. 

Energy Efficiency

Of the many types of roofing materials available on the market, spray foam roofing has a high R-value of 6.5. An R-value measures a material’s resistance to thermal air flowing through it. R-values have a rating scale of 1 to 7, and the higher the R-value, the better insulation the material has. 

Because it doesn’t absorb heat, spray foam roofing increases energy savings. Not only does this cut back on heating and cooling energy costs, it also helps maintain stable temperatures inside your home. 

Environmentally Friendly

Because SPF roofing doesn’t have to be replaced frequently and doesn’t require tearing out the old existing roof underneath, spray foam roofs cut back on roofing material waste in landfills

On top of that, because of its energy efficiency, spray foam roofs cut back on power consumption for cooling and heating your home. 

Lightweight

A spray foam roof coating is lightweight and doesn’t put a heavy burden on your home. Ultimately this helps your home’s foundation and structural integrity last longer. 

Cons of Spray Foam Roofing

Overspray

When a new SPF roof is installed, overspray can be a problem. Wind can carry the foam away from the roof and it might land on the yard or cars below. It may be necessary to cover cars or landscaping to prevent overspray from landing on them when your roof is installed. 

Vulnerable to UV Rays

A spray foam roof must be covered with a protective elastomeric layer, otherwise a spray foam roof will quickly deteriorate when exposed to the ultraviolet rays of the sun. Typically, these elastomeric membranes are made of silicone, acrylic, or urethane. 

FAQ About Spray Foam Roofing

Can I walk on a spray foam roof?

Yes. Spray foam roofs can easily accommodate foot traffic and walking on a spray foam roof will not damage it. Despite being called “foam,” a SPF roof is anything but spongy and foamy. Once it hardens a spray foam roof is hard and durable and can hold up under weight. 

However, it is best to wear soft-soled shoes on your SPF roof, as like with most roofing materials, hard-soled shoes can damage your roof. 

Does spray foam roofing rot your roof?

Spray foam roofing will not rot your roof. However, improperly installed roofing may allow moisture to get trapped between the insulation and the roof, which can lead to water damage or rot. Hire a trustworthy roofing contractor who is experienced with installing spray foam roofs. 

What colors does spray foam roofing come in?

Spray foam roofing is generally available in light colors such as white, gray, or tan. Light colors reflect the sun better than dark colors, which in turn keeps the inside of your home cooler. 

Is a Spray Foam Roof Right for You?

Spray foam roofing is a low-maintenance roofing material with a lot of benefits. It’s a durable roofing solution that is weather resistant, energy efficient, easy to install, eco-friendly, and long-lasting. 

Not every roofing company performs spray foam roofing, so if you’re looking for a contractor to install a spray foam roof, then find a roofing pro today.

Main photo credit: brizmaker / Canva Pro / License

Danielle Gorski

Danielle Gorski lives with her family in Texas. She has a degree in Professional Studies and a minor in marketing. Her hobbies include reading, drawing, and writing.