Cost of a Spray Polyurethane Foam Roofing System
Our sales team is asked every day, “How much does a Spray foam roof cost?”
As of 2021, an average 20,000 sq. ft. commercial roof will usually cost between $4.00 and $6.00 per square foot to install a spray foam roofing system.
However, many factors can affect the cost, including:
- The size of the roof
- The thickness of spray foam
- The condition of the existing roof
- The thickness of coating/warranty length
- Access to the roof
- Type of warranty
- Type of maintenance plan
Here at West Roofing Systems, we’ve installed over a 60,000,000 sq. ft. of roofing since 1979.
In this article, we’ll break down the factors that influence the 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.
And just so you’re aware, we only write articles from true events and experiences. Every piece of content written at West Roofing Systems is produced in-house. Every article is reviewed and edited by a roofer/salesman with more than 30+ years of experience in the field.
Let’s get started.
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
The thickness of the spray foam
On average, it costs $1.65 – $2.25 per square foot for materials and labor on a typical SPF roofing system, which is a 1.5-inch 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 higher R-Value your roof will have.
R-value is the measure of insulation (resistance to heat flow) for a material. All states or regions require 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 the existing roof
The condition of your existing roof will be a crucial factor in the cost of your new spray foam roof. There are three options when dealing with the existing roof:
Before SPF Roofing Installation
Clean and prepare existing roof – $0.10 – $0.75 per sq. ft.
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 over existing roof – $0.60 – $0.80 per sq. ft.
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. ft.
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.
The thickness of coating and warranty length
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.
The length of the warranty fluctuates with the amount of coating.
- For a 10-year warranty, 20 mils of coating are installed.
- For a 15-year warranty, 20 mils of coating are installed.
- For a 20-year warranty, 20 mils of coating are installed.
Access to the roof
WRS Employee Rappeling for Sloped Roof Installation
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.
It is recommended that your spray foam 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.
What should you do now?
There are a few things you can do. One thing is to learn more about spray foam roofing. Here are a few popular blog posts:
- What problems can spray foam roofs have?
- How does a spray foam roof compare versus a single-ply roof?
- How long will a spray foam roof last?
Or you can read a few spray foam case studies:
- Metzenbaum Center – Learn how re-covering a roof with spray foam came in under budget while completing the job in 1/3 of the time.
- MTD – Learn how 3 spray foam robots and a 14 person crew finish a 384,000 sq. ft. spray foam roof in 52 days.
Or if you want to learn about spray foam quickly, check out this guide: