How much does it cost to have foam roofing installed?

Reviewed by Adam Graham remodeling expert. Written by Fixr.com.

Spray polyurethane foam roofing, also called spray foam, is used to repair and reinforce residential and commercial roofs. This material is sprayed on roofs and creates a solid protective layer by expanding into foam. Spray foaming has become a popular choice as it’s a durable and lightweight way to enforce a surface, which also puts less stress, wear, and tear on the roof. At the same time, spray foaming is an eco-friendly approach that can lower energy bills. Roofs reinforced with a layer of spray foam are resistant to water damage and prevent standing water, which is an issue with other roofing types and can require costly repairs.

Homeowners spend between $8,000 and $14,000. Most homeowners spend around $11,000 to install 1,500 sq.ft. of two-layered, medium density spray foam reinforced with a silicone coat and a sealant. On the low end, you can opt to install a one layered, low-density spray foam with an acrylic coat for around $6,000. On the higher end, you can have a three-layered, high-density spray foam enforced with a silicone coat and high-quality sealant installed for $20,500.

Cost to Install a Spray Foam Roof

What Is a Foam Roof?

A foam roof is a popular way to reinforce roofing and protect against water and storm damage. There are many benefits of spray foam roofing because the polyurethane material sprays smoothly onto the roof’s surface before expanding into foam for a solid layer of reinforced protection. Many homeowners with ongoing leaks or those that live in areas with high annual rainfall choose spray foam roofing for durability and energy efficiency. If you want to improve your roof’s insulation and prevent costly water damage, then a foam roof may be a smart investment. Several layers of foam roofing material work best at preventing costly problems and damage, which is why foam roofs are used not only for houses but also for commercial buildings like schools, hospitals, and shops.

Average Cost of Foam Roofing per Square Foot

The typical cost to spray foam roof runs between $4 and $8 per sq.ft., with basic material and labor included. As the square footage increases, more materials and more workers are needed to cover the whole surface, ultimately adding to the cost. Using the average spray foam roof cost per sq.ft., we have calculated the average spray foam roofing installation costs based on the most common roof sizes.

Spray Foam Roofing Cost by Foam Density

In most cases, a standard SPF roof with a standard layer of foam is between $0.30 to $1.50 per square foot. The thickness of the sprayed foam depends on where you live, and the outside conditions in your area. For instance, if you live in an area with harsh weather (high heat, heavy rainfall/snowfall), the roof needs to provide a higher level of insulation, requiring a spray foam with a thicker density.

The thickness of spray foam depends on the desired R-value, an indicator used to measure a roof’s insulation. There are three levels of foam density: low-density, medium-density, and high-density spray foam. The denser the foam, the higher the insulation of the building, and with it, the R-value. For instance, high-density spray foam has an R-value of 6.6 (or higher) per square inch, which means that if you want to achieve an R-25 value of insulation, you need to have a 4-inch layer of spray foam (25/6.6=4).

Low-Density Spray Foam

Low-density spray foam is the cheapest option among the three, costing around $0.30 to $0.65 per square foot. Typically, it comes with a lower density ranging between 0.4 to 1.4 pounds per cubic foot and an R-value lower than 3.6 per inch. While it’s not as effective for insulation as medium and higher density spray foam, it’s perfect for installing in areas with mild weather as it’s the cheapest option.

Medium-Density Spray Foam

Medium-density spray foam is also known as closed-cell foam with an R-value of 5.5 to 6.6 per inch. The cost can range between $0.90 to $1.20 per square foot. It can be applied as low-pressure or high-pressure two-component spray foam depending on how it’s applied - whether it’s on a smaller area or a larger one. It provides the best balance between cost and insulation, making it ideal for those wanting to get a satisfactory level of insulation and waterproofing while staying on a budget

High-Density Spray Foam

High-density spray foam roofs usually come at the cost of $1 to $1.50 per square foot. As its name suggests, high-density spray foam has the densest structure out of all insulation types. It provides an R-value greater than 6.6 per inch. Similar to medium-density, it comes in the form of a closed-cell type, provides a higher level of insulation, and offers the best waterproof mechanism out of the three.

SPF Roofing Cost by Cell Type

Spray foam usually comes in two types: open-cell and closed-cell. One is better than the other in different situations and settings, so there is no definite winner in the open-cell vs closed-cell foam comparison. Both types come with a different level of energy efficiency and density that impacts the cost and provide a different level of insulation at the same time.

As their name suggests, open-cell foam is made of cells that aren’t fully encapsulated, making them softer and more flexible. On the other hand, closed-cell foam is made of completely closed cells, making them more rigid and stable. The table below lists the material costs per board ft. for open-cell and closed-cell spray foam roofing.

Open-Cell Spray Foam

The typical cost of open-cell ranges between $0.30 to $0.65 per board foot plus installation. Open-cell systems allow moisture to get through, so they require a vapor retarder, which increases the overall project costs. On the other hand, open-cell spray foam is softer and flexible, resembling a sponge once applied. Due to the weaker durability, it’s not as common in roofing but is more often found in spray insulation applications. However, the R-value of open-cell SPF is 3.7 to 4 per inch, making it a cheaper roofing solution that works well in tight spaces due to its expansion capability. It’s also lightweight and blocks out sound well.

Closed-Cell Spray Foam Roof

Closed-cell spray foam roof costs between $0.90 and $1.50 per board foot plus installation. It’s denser, weighs around 2 pounds per cubic foot, and is more tightly pressed together, preventing air and moisture from penetrating it. The typical R-value of open-cell sprayed polyurethane foam is 4.9 to 7.1 per inch, which also provides water resistance and helps curb the mold growth. Closed-cell SPF has a built-in vapor retarder and is used in both roofing and insulation applications. While it’s a more expensive version, it’s sustainable and results in greater cost-savings over time than other roofing option

Foam Roof Coating Cost

The protective silicon or acrylic foam roof recoating costs between $0.15 and $2.50 per sq.ft. for just the materials. Adding a coat of elastomeric membranes gives it an additional layer of UV protection. The coating is used in all roofs and improves the waterproof properties of an SPF roof, makes it more impact-resistant, and increases its fire rating. Depending on where you live, your roof may require one or two layers of coating. Two types of coating are available: silicone and acrylic, each with a different cost and fit for various settings. Some contractors apply an acrylic coating and then upgrade it to a silicone coat. Others may mix the two types to maximize energy efficiency and minimize the foam roof recoating cost. The average price per sq.ft. of foam roof coating is outlined below.

Roof Acrylic Coating

Acrylic polymers are roof coatings designed specifically for roof applications and are one of the cheapest coating materials at $0.15 to $0.75 per square foot for the material only. It’s made of a fully adhered elastomeric membrane five to ten times thicker than house paint. This means that they aren’t mechanically attached but rather sprayed on the roof as a liquid, which forms a solid membrane as it dries. It’s widely used because it is durable and easy to use. Additionally, because of the compounds in it, acrylic coatings have minimal toxicity. Some contractors will first apply an acrylic coating and then upgrade it to a silicone coat. Others may mix the two types to maximize energy efficiency and minimize costs.

Silicone Roof Coating

A silicone coating costs between $1.40 and $2.50 per square foot for the material only. It is applied to make the foam more resistant to the elements, especially water. The initial coat is usually included in the price. Typically, contractors charge an additional 10% to 15% of the overall cost for each added coat of silicone, which is around $0.15 to $0.40 per sq.ft. The extra silicone coat is usually embedded with granules for more protection against the elements and the environment. This silicone coating improves the efficiency of your roof by reflecting the sun and insulating the home, contributing to lower overall utility costs and energy savings.

Spray Foam Roofing Installation Cost

Spray foam roofs are applied using a spray process involving a chemical reaction that expands the sprayed material to 20 times its initial size. The basic necessary materials and equipment average $2 to $3 per square foot. As for labor cost, most roofers charge $2 to $4 per square foot. If you want to install an additional layer of spray foam and reinforce it with a silicone coat and a sealant, it would add around $1.35 to $2.35 per square foot.

The roofing contractor will first need to prepare the surface for the spray foam material by getting rid of all dust, debris, and dirt. Spray foam roofs can only be installed on sunny, dry days to be effective. This requirement will dictate the project’s schedule. Any oils, grime, or contaminants on the roofing surface affect how the foam adheres. If you want to prevent future water and moisture damage, you may choose to go with a thin layer called an underlayment. It’s a waterproof membrane that costs around $3 to $6 per square foot, installed.

The process of installing spray foam roofing is similar to an insulation project. The foam is sprayed onto the surface as a liquid, which later hardens into a solid around 20 times its original size. Foam roofing comes from a chemical reaction and requires special equipment, it is recommended to hire a professional instead of doing the work yourself. A basic foam roof takes a day or two to spray, depending on the pitch, slope, and size of the surface. Generally, roofing contractors charge $2 to $4 per sq.ft. rather than an hourly rate because the length of their work depends on the size of the roof and the required materials.

Cost of Foam Roof Replacement

Replacing a foam roof costs around $4.50 per square foot, instead of roofing-over, which costs between $2 and $3 per square foot. Typically, spray foam roofs last around 10 to 20 years before needing any repairs or replacements. They can last over 50 years with proper care. However, any major damage to the overall roof structure, like significant water damage, rot, and mold issues, may require replacement.

To ensure your roof lasts and protects your home properly, you need to have it regularly inspected by a professional. A professional roof inspection costs $100 to $600 and is recommended once every one to three years, in addition to self-inspections twice yearly. Often, the cracks and flaws you notice can be repaired, but some signs indicate it needs to be replaced soon. One of those signs is spots with leaks and mold on your upper walls. If you notice these, it means that the quality of your roof is deteriorating and needs to be either repaired or replaced.

Cost Factors

The larger the roof’s surface area, the more costly the installation of the roof. The exact costs fluctuate due to many factors, such as the size of your property and the obstacles that arise. Another important factor is the necessary materials and equipment the roofers use. You can also opt for additional silicone or acrylic roof layers, which will add to the overall cost.

As we mentioned above, spray foam roofs must be installed very precisely, so easy access to your roof is key. If contractors must deal with vegetation, foliage, or have other difficulties when accessing the roof, it will delay them and increase labor costs. Additionally, roofs with lots of architectural details or obstructions, such as skylights, pipes, and chimneys, may require more time to spray the roof, increasing the overall cost based on the increased labor time. If contractors need to use additional lifts and safety equipment, they charge more, too. Remember that roofers check the existing insulation to make sure it is not wet. If the insulation is wet, it must be removed and replaced before the spray foam roofing insulation.

Maintenance

Roof repairs cost $3 to $10 per sq.ft. You can save money on roofing repairs and maintenance with a spray foam roofing system because these roofs are easy to care for and durable. However, these must be maintained and repaired to ensure they last for the predicted lifespan of 10 to 20 years.

Some preventative maintenance includes regular roof cleaning, which costs $0.10 to $0.60 per square foot, depending on the cleaning method you choose. Routine cleaning of your roof and gutters preserves them from the elements and cleans any debris, leaves, or branches that may have fallen on it. This ensures that it will continue to provide long-lasting protection and insulation. That is why gutter cleaning is very important too. With an average cost of $0.70 to $3.20 per linear foot, gutter maintenance is a good investment to ensure there are no clogs that could cause water damage to the roof.

Plan to apply a new silicone restoration coating every ten years or so, which costs about $1.30 per square foot. This means that to replace a 1,500 square foot roof, you would pay around $1,950 plus installation costs. In general, you can expect to pay a little more than one-fourth of the total cost of your original foam roofing system project and installation.

Foam Roof vs Shingles Cost

The average cost to install roof shingles varies greatly depending on the type of shingles you will use. The complexity of the roof, the shingle material, the style of roof you choose, and the additional work needed impact the overall cost. Roof shingles are installed over a felt underlayment and a plywood roof deck by overlapping the layers on the roof. While they can be very expensive, the average cost is lower than spray foaming, $3.50 to $5.50 per sq.ft. compared to $4 to $8 per sq.ft. for spray foam roofs. Roof shingles can last for 20 to 60 years depending on the type while spray foam roofs need to be refreshed every 10-20 years.

Spray foam is commonly used for flat roofs, while roof shingles are more fit for low- to medium-pitched roofs. This is because flat roofs are more prone to standing water and leaks, against which spray foam is far more effective than shingles. Flat roof repair and replacement costs can be higher because not all roofers specialize in flat roofing materials.

Roof shingles can also be installed on high-pitched roofs, but this makes installation, repairs, and maintenance a bit challenging.

Enhancement and Improvement Costs

Roof Underlayment

You can opt to install an underlayment under the roof for a cost of around $3 to $6 per square foot with installation costs. Roofing underlayment is applied under all roof materials directly on the roof deck before installing the spray foam. It’s a membrane that adds an additional layer of protection and helps prevent moisture from leaching in through your foam roof. The main materials used for underlayment are asphalt-saturated felt, non-bitumen synthetic, and rubberized asphalt.

Foam Roof Sealant

A great option for preventing future leaks is to apply roof sealant, which typically costs around $100 for 5 gallons plus an additional $0.50 to $2.50 per sq.ft. to have it installed by a professional. Roof sealants repair small cracks, punctures, or gouges on the roof and prevent water or moisture from accumulating. However, areas with bigger damage may require repair or roof replacement. When you apply a sealant, it will absorb damage from the sun, snow, ice, and water instead of your roof. It provides an additional layer of protection. Keep in mind that the sealant you use has to be compatible with your spray foam roofing system.

Additional Considerations and Costs

• Chemical fumes. Keep in mind that during installation and while it’s drying, spray foam may release chemical fumes. Talk to your contractor about whether you can be in the home when they are spraying your roof. You may need to leave the house to avoid inhaling chemical fumes. You should also avoid being present in the home if you’re allergic or sensitive to the chemicals used in spray foam.
• Permits. Typically, you will need a permit to build or replace a roof of any kind. If you are only making small repairs on less than 100 square feet, you don’t usually need a permit, though requirements and laws vary for each geographic locale. You should expect to obtain permission and approval from your homeowners’ association before installing your new roof, if applicable.
• DIY. While installing spray foam roofing can be a DIY job, it can become quite messy. Roof jobs are quite risky, so any mistake can result in injuries or thousands of dollars in roof damage. On the other hand, licensed contractors have the right equipment and knowledge to spray foam roofs, so it’s always recommended to hire a professional to do the job.
• Certification. Consider getting a LeakFREE® Roof Certification for your spray foam roof. It's the highest roof certification given by the National Roof Certification and Inspection Association. It is a federally trademarked document that guarantees that your roof will remain LeakFREE® for up to five years, or a member of NRCIA will repair it. The certified inspector from NRCIA will examine and analyze the interior, exterior, perimeter, attic, and rooftop to ensure it meets the highest safety standards before issuing the Certification.
• Warranty. Make sure you check the warranty before agreeing to spray foam roofing installation. Most companies offer a 15, 20, 25, or 30-year warranty. Also, check the warranty for any existing roof shingles because brands have stipulations for spray foam installation.
• Roof pitch, shape, and style. The installation process for spray foam roofing takes longer on roofs with a greater pitch or a unique shape or style. In these cases, roofers need additional restraints and protection, which takes up more time and increases the overall labor and polyurethane foam roofing cost.
• Roof material. The cost to spray foam roof may vary slightly by existing roof material. The good thing about spray foam is it can be applied to a wide range of roofing materials, including TPO, EPDM, modified bitumen, metal, or built-up roofs.
• Extra foam layer. Adding an extra layer of foam costs around $0.50 to $2.50 per sq.ft. Foam roofs naturally lower energy costs because they are lightweight and white, reflecting the heat naturally. You can potentially lower your energy bill even more by adding an extra layer of foam to make the roof thicker and more reflective.