Cost of a Spray Polyurethane Foam Roofing System
Our sales team is asked every day, “How much does a Spray Polyurethane Foam (SPF) roof cost?” and it’s not easy to give just one answer.
There are many factors that can affect the price of a commercial roof; from the weather to the location to the material choices.
Here at West Roofing Systems, we’ve installed over a 60,000,000 sq. feet of roofing domestically and internationally and during that time we have noticed that it can be tough to answer, “How much does a Spray Polyurethane Foam (SPF) roof cost.”
So, in this article, will review the average price of an SPF roof and break down factors that could change your price. Keep in mind that when you are looking to invest in a new roofing system, it’s a good idea to get a couple of quotes from different contractors.
For an average 20,000 sq. foot commercial roof, it will usually cost between $4.00 and $7.00 per square foot in materials and labor to install a typical SPF roofing system. This price range is for an SPF roof of average thickness and building structure.
To get the best roofing system for the right price, you will need to consider these key factors:
The Size of Your Roof
When a contractor is pricing a new roofing system, the economies of scale start around 20,000 sq feet; which means after 20,000 sq. feet you can start saving money per square foot of roof.
Other size factors that can impact your cost also include:
- The logistics of moving equipment up to and across a large roof
- Debris removal costs
- Material transport costs – this cost can take up 2-3% of the total project costs
Thickness of the SPF
On average, it costs $1.65 – $2.25 per square foot for materials and labor on a typical SPF roofing system, which is a 1.5in layer of foam. Although there are reasons that a building will need a thicker layer, the most common reason is for energy efficiencies.
The thicker you make the foam layer, the high R-Value your roof will have. An R-value is the measure of insulation (resistance to heat flow) for material. All states or regions have that require that a roof system has a minimum amount of thermal resistance on commercial, industrial, and institutional buildings.
Basically: the higher the R-value, the more the material insulates.
You can work with your architect or contractor to compare the energy cost savings to the additional SPF costs to find where you can save money.
Condition of Existing Roof
The condition of your existing roof will be a crucial factor in the cost of your new SPF roof. There are three options when dealing with the existing roof:
Clean and Prepare Existing Roof (no significant alterations) – $0.10 – $0.75 per sq. foot
When you have a solid roof that doesn’t require major modifications or corrections, the contractor will need to clean and prepare the roof, so the foam adheres properly.
There are four ways a contractor can prepare a roof for SPF installation:
- Air Pressure Cleaning
- Dry Vac/Ballast Removal
- Wet Vac for dirt, gravel and dust removal
Recovery Board Fastened on Top of the Existing Roof – $0.60 – $0.80 per sq. foot
Recovery boards are commonly used to recover and improve the application surface. This process could be used to cover joints and to provide a separation layer between the existing and new roofing systems.
Stripping and Removal of Roof – $1.00 – $2.00 per sq. foot
There are two main reasons a contractor would need to strip and remove your existing roof.
- A building can’t have more than two roofing systems. This means if you currently have two roofs, your contractor will need to remove them before installing your new roof.
- If your roof is damaged, saturated or unstable, your contractor will need to strip the existing roof to install a new working roof.
When the SPF layer has been completed, it is then sealed with a layer of silicone and embedded granules. These layers protect the roof and foam from UV light, weather, and impact. The cost is between $1.75 and $2.30 per sq. foot in labor and materials to install.
There is a two-coat minimum of the silicone coating. You can increase the thickness of the silicone layer depending on the warranty you choose. For example, a 20-year warranty will need a thicker layer of silicone than a 10-year warranty.
Access to Roof
Not all commercial roofs are flat; not all roofs can be walked on. Additional costs can occur when your contractor has limited access to the facility roof.
Height and distances of the roof can be multipliers for the cost of your SPF roof installation. Sloped roofs often require the contractors to use a man lift or rappelling gear for SPF installation. Contractors may need to rent conveyance equipment such as a crane or passenger hoist to move the crew and equipment.
When teams are working on secure locations, such as an airport, they often need to keep up their Secure Identification Display Area (SIDA) authorization. This includes background checks and fingerprinting, which is an added cost for the contractors.
Type of Warranty
When you install a new SPF roofing system, you will have a few warranty options. The three most common types of warranties include:
- Contractor’s Warranty – No expense or less than $1,000
- Manufacturer’s Product Warranty – Low cost and low coverage
- Manufacturer’s Full System Warranty – $0.08 – $0.15 per sq. foot
Here’s an entire article about spray foam roof warranties.
You can save a lot of money by simply keeping up with the maintenance of your SPF roofing system. There are two types of maintenance: preventative maintenance and a restoration coating.
It is recommended that your SPF roof is inspected twice a year:
- Fall Inspection – Clear leaves from drains, prepare for winter
- Spring Inspection – Look for damage from the winter weather
A visual inspection including general maintenance is a rather inexpensive way to maintain the integrity of your SPF roof at $0.2 – $0.5 per sq. foot. Any roofing contractor can perform inspections on your SPF roof, but you should hire a certified SPF roofing contractor to perform repairs.
Silicone Restoration Coating
Silicone Restoration Coating is an economical and environmentally friendly alternative to re-roofing. The average cost range for a silicone restoration coating is $2.00 – $5.00 per sq. foot.
Your contractor will make sure that the existing surface is clean and dry, and apply a new layer of silicone coating to the roof. This will restore the top layer of your roof and repair any punctures or other issues your roof is experiencing.
So, there you have it – our costs for spray polyurethane foam roofing systems. When you include the SPF, silicone coating, size, and access to the facility, warranty, and maintenance, the average cost of an SPF roofing system is between $4.00 and $7.00 per square foot. It’s important to remember that based on your roofing contractor, location, and building, these prices will vary.
*Cost ranges are general estimates, each roofing system is unique and costs can vary. Please seek a professional quote for more specific and reliable costs.
Author: Jack Moore
Jack Moore is President and CEO of West Roofing Systems, Inc. With 21 years of SPF Roofing experience, West Roofing Systems has received numerous accolades for his leadership in the commercial roofing industry, including 18 industry excellence awards from the Spray Polyurethane Foam Alliance. He is an active member of the National Roofing Contractor’s Association and the Spray Polyurethane Foam Alliance.