Pros and Cons of SPF

Pros and Cons of Spray Polyurethane Foam (SPF) Roofing Systems

We all want more “bang for our buck” in today’s economy.  So, why should your commercial roofing system be any different?

SPF Roof on School
SPF Roof on School

While the choice is ultimately up to the building owner, we want to point out a few pros and cons to Spray Polyurethane Foam (SPF) Roofing Systems.

At West Roofing Systems, we’ve been installing spray foam roofs since 1979, so we’ve been around the block with everything spray foam-related.

In this article, we’ll share what we know about the pros of spray foam roofs, but also all the cons. The goal of this article is to help you decide if a spray foam roof is the right choice for your building.

Let’s begin.

Pros of Spray Foam Roofing

Easy Installation

The ease of installation can save you time and money with your new SPF roof. The application of the foam and coating is quick and can be applied with usually no interruption to the daily routine of the facility.

Spray Polyurethane Foam Application
Spray Polyurethane Foam Application

SPF roofs are installed by spraying a liquid on the existing roof and allowing it to expand into foam.

This process means that the foam can conform to all roof shapes and types, even irregularly shaped roofs.

After cleaning the existing roof, the SPF roof can be applied directly over asphalt, shingles, concrete, metal, and wood.

Energy Efficient

SPF roofing delivers thermal, air, and moisture barriers to provide the highest R-value per inch, which means the material provides better insulation for the building.

The polyurethane foam keeps heat out in the summer, in during the winter, lowering energy costs for facility owners. The silicone top coating resists UV light, protecting the foam and reduces heat absorption (emissivity).

Easy Maintenance

Once an SPF roof is installed, it requires minimal preventative maintenance and repair. If properly maintained, your SPF roof can last over 50 years.

SPF roofing systems should be inspected semi-annually, in the Spring and again in the Fall. Additional inspections are also suggested following any event that might have caused damage to the system.

In the event where a silicone recoating is needed, there’s no tear-off of the existing materials; you apply the new coat on top of the current system.

Seamless and Waterproof

Seamless SPF Roof
Seamless SPF Roof

Seams and penetrations are the primary sources of leaks in roof systems, spray foam eliminates this vulnerability.  Since the spray foam mixture is applied as a liquid, it can fill gaps, seams, and cracks in the existing roof and substrate.

The application of the polyurethane foam allows the contractor to level out the roof to decrease the chance of ponding water. The foam material can expand and contract with the building in accordance with outside temperatures, reducing the likelihood of cracks and splitting.

Renewable and Sustainable Roofing

Spray foam roofs create little to no waste during their lifetime. In most cases, there is minimal stripping of the original roof, and the SPF roof is installed on top – eliminating the need for costly roof tear-offs and waste.

The materials that are used for SPF roofing systems are also environmentally friendly:

  • Zero Ozone Depleting Potential (ODP)
  • Low in the Emission of Volatile Organic Compounds (VOCS)
  • Free from Chlorofluorocarbons (CFCS)
  • Ultra-Low Global Warming Potential (GWP)

Read more: How is a spray foam roof renewable?

Cons of SPF Roofs

Not All Contractors are Created Equally

SPFA Certifications
SPFA Certifications

The application of the spray foam is a process that needs to be done correctly from the beginning. The contractor needs to be precise with the application and have a solid understanding of the chemicals they are using.

It doesn’t take a large crew to install an SPF roofing system, but it requires a high degree of technical knowledge and experience.

The Spray Polyurethane Foam Alliance (SPFA) has an ISO-17024 compliant certification program that has multiple levels, requires the contractor to pass an exam and meet the criteria for certification.

If the roofing system is installed incorrectly, it can be detrimental to the lifespan of the roof and underlying substrate.

Limited Installation Window

SPF can only be sprayed during specific weather conditions. Installation of an SPF roofing system cannot be performed when there is ice, frost, surface moisture, or visible dampness on the existing roof.

While the installation does not interrupt the daily functions of the building, the weather requirements can leave only a small window of opportunity.

Overspray Potential

Spray Polyurethane Foam Application Team
Spray Polyurethane Foam Application Team

Since the spray foam roof is installed by a spray application, there is a risk of the wind carrying overspray onto surrounding cars and other surfaces. While this does not pose a health concern, it is a concern for surrounding property.

At West Roofing Systems, we take extra care to prevent overspray. We have a few different techniques that we practice to protect surrounding property.


Spray foam roofing systems should be inspected twice a year whether there is known damage or not. And especially after weather events that could cause damage: such as hail storms, tornados, and hurricanes. Small cracks, gouges, or punctures can be repaired with an elastomeric sealant compatible with the spray foam system. So you need to keep your SPF roof in mind at all times.

Accurate Repairs Needed

Spray foam does not have as high of resistance to punctures or damage. If your SPF roof is damaged, you must call an SPF contractor to perform the repair. The repair needs to be made with silicone because typical roofing repair materials do not adhere to the silicone coating.

Spray Polyurethane Foam Roofing Systems are becoming the go-to roofing for commercial, industrial, and manufacturing facilities that are looking for a sustainable, economically efficient option.

At West Roofing Systems, our goal is to get you a long-lasting, durable roof that will protect your facility. That includes working with our award-winning team to choose the best roofing systems to meet your needs.

Want to Learn More About Spray Foam Roofing?

Download our free guide below which includes:

The spray foam roofing cheat sheet - download now

  • Emma Hallberg


    Hi, can SPF roof be installed on a sloped roof? Thanks

  • Jerry


    Can ravens and other birdspeck holes in the roof?

    • Aubrey Barto


      Early Spray Polyurethane Foam roof designs were susceptible to occasional mechanical damage by birds (crows and seagulls). This phenomenon has been stopped with the inclusion of granule surfacing embedded into the top coat.

  • Vijay g


    Can it be used for computer server room roof insulation

    • Aubrey Barto


      Yes! That is a great use for SPF Roofing.

  • Yoko Olsgaard


    We have squirrels that like to jump off tree branches and run marathons on our Eichler style home. How do SPF roofs perform under daily squirrel runs?

    • Unless they’re radioactive 50 lb. squirrels, I don’t see where squirrel traffic will be a major problem. As with any roof though, it’s always a good idea to enter into a maintenance program to ensure that all is well on the roof. Building/home owners tend to forget about the roof, out of sight out of mind kind of mentality. Having a professional make yearly inspections is a good idea

  • Janet Surkin


    Can this material be used if there are vents and HVAC equipment on the roof?

    • Hi Janet, yes. you can spray foam on roofs that have vents and HVAC equipment. We will close those off during application, but once that’s done, we’ll open them back up and you’ll be good to go.

  • Gene


    Can a foam roof be applied on top of a built up roof after the gravel is removed or should the gravel and/or the built up system be removed first?
    Once the foam roof is installed is it coated with a silicone coating?
    Roughly how much does it cost per square foot to install a foam roof system?

    • The dirt and loose gravel needs to be removed first, typically with a hydro-vacuum process (vac truck), also need to verify that the existing roof assembly is dry and there is only 1 roof in place (building code only allows for 2 roofs in place at one time). Ultimately, once cleaned and prepped, and verified that the roof is dry, a gravel built up roof is a very ideal surface to apply foam to.

      Yes. A spray foam roof is always coated, usually w/silicone.

      Spray foam roofing usually cost between $4-$7 per sq. ft.

  • pattie


    What areas of the country – weather zones – can this roof be used? What is the R-value of the roof? Can it be installed over rubber roof? Can it be installed over modified bitumen roll roofing? Does your estimate of $4-7/ sf include the silicone layer? How often does the silicone layer have to be reapplied?

  • Kusum Shekhlia


    What is the effective useful life of this product?

    • A spray foam roof can be the last roofing system you’ll ever need on a building. Since a spray foam system consists of spray foam, coating, and granules, after 10-20 years, some of the coating and granules will naturally wear away. At year 10-20, a contractor will add more coating and granules. The foam never gets touched and never loses R-value. Spray foam is sustainable and renewable. Hopefully this helps!

  • can it be installed over a tpo roof?

  • tom naraghi


    can you spray this stuff on flat concrete roof to make the needed 1/4 per foot of slope to go from 1.5″ to 4″ of total slope

    • Hi Tom. Yes! With spray foam being “spray-applied”, the slope can be customized to fit the needs of your roof. Thanks!

  • steven reeves


    I have a ballasted EPDM roof, if the rock is removed and the EPDM is cleaned and foam sprayed is this enough weight to stop the insulation for bumping up.

    • Hi Steven, since the ballasted EPDM roof is no longer fully-adhered with the rock being removed, a cover board needs to installed before spray foam can be installed. This should stop the existing insulation from bumping up. Hope this helps!

  • kaye Shurman


    Do the silicone coatings come in different colors or only white?
    Are foam roofs fire resistant?

    • Hi Kaye! The silicone coatings come in different colors. Some want the coating color to match their building, so we’ve done an assortment of different colors. But most choose white for the reflectivity of the sun. And yes, spray foam roofs are fire resistant. Thanks!

  • Marc Dick


    Please explain how SPF is “sustainable and renewable”?

    • Hi Mark, say you get an SPF roof with a 20-year warranty. For R-value purposes, you need 1.5 inches of SPF. On day 1, your roof would get 1.5 inches of foam and 30 mils of coating to protect the roof. After 20 years, the 30 mils of protective coating would naturally wear away to 7-8 mils. Now a contractor can clean the roof, and add more coating to bring the level of coating back to 30 mils. This would grant you a new 20-year warranty. The foam is never touched and it doesn’t lose any of its insulating properties. The “recoat” process can be repeated over and over again. Hope this helps!

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