As of April 2023, the cost of a spray foam roof is likely between $6 – $12 per square foot.
The average price for a spray foam roof costs anywhere between $6 and $12 per square foot depending on manufacturer material costs, the difficulty of installation, warranty length desired, R-value desired, the amount of wet insulation that needs to be removed, and several other factors.
Many other factors can push the cost past the $6-$12 threshold.
At the end of the article, we’ll explain other factors related to the lifetime costs of a commercial roof, such as roof renewability and future energy costs.
Let’s get started.
The size of your roof
The larger your roof is, the less it’ll cost per square foot. This is because of the safety setup and overhead costs that go into every roof.
For example, a 1,000-square-foot roof could cost $12 per square foot. A 100,000 square foot roof could cost $6 per square foot.
It’s the same as buying a 24-pack of paper towels versus buying a 4-pack, which one is less expensive per roll?
Condition of the existing roof
One of the best advantages spray foam has over other roofing systems is that it always minimizes tear-off. In most cases, spray foam can be installed right over your existing roof.
However, sometimes because of existing conditions, there can be more prep work.
Here are a few things that can happen:
- If you already have two roofing systems installed, at least one roofing system will need to be completely removed before installing any other roofing system (including spray foam).
- No roofing system can (or should) be installed over wet insulation. If you have wet insulation, it needs to be removed and replaced before installing another roof system. This can be 5% or 100% of your roof. An infrared inspection and/or the pulling of core samples will determine the amount of wet insulation the roof has.
- A spray foam roof needs to be installed over a fully-adhered existing roof system. If your existing roof isn’t fully-adhered, a coverboard may need to be installed first before spray foam can be installed. An example is a TPO roof that’s only attached to the insulation below at the seams. In this example, a coverboard would be needed.
The thickness of spray foam
The more product that’s used for your roof, the more costly it’ll be.
Spray foam needs to be installed at a minimum of 1” thick to cure and perform properly. However, most roofs require more than 1” of thickness.
You might be wondering…why do some roofs require more spray foam than others?
A roof that needs to be completely removed down to the deck is considered by building code as “new construction”. This means there’s a minimum R-value requirement.
In Ohio, it’s an R-25.
Because spray foam has an average R-value of 6.5 per inch of thickness, about 4 inches of spray foam would need to be installed.
If a roof has ponding or standing water that doesn’t run off the roof, there may be a sloping issue. One of the best advantages that spray foam has over other roofing systems is that spray foam is fluid-applied.
This means adding slope is very easy…just pull the trigger and install more product. Other roofing systems need to cut the membrane and make the slope with insulation boards, which is time-consuming and expensive.
A common installation (on a roof with an internal draining system) is to install 2 inches of spray foam around the perimeter and all penetrations, and 1 inch of foam near the drains.
Some buildings are stricter with climate control, such as IT companies and chemical plants. These buildings use more cooling/heat than normal businesses do. In this case, a higher R-value may be targeted, which requires a larger amount of spray foam.
The thickness of the coating and warranty length
After spray foam is installed, a protective, “elastomeric” coating must be installed. Coatings protect the spray foam from UV rays, which can degrade the foam. The most common elastomeric coating is silicone.
The length of the warranty fluctuates with the amount of coating that’s installed.
- For a 10-year warranty, 20 mils of coating are installed.
- For a 15-year warranty, 25 mils of coating are installed.
- For a 20-year warranty, 30 mils of coating are installed.
The more coating that’s used, the more the project will cost.
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 roof.
The height and distance of the roof can influence the cost of your installation. Sloped roofs often require the contractors to use a man lift or rappelling gear for 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 in secure locations, such as an airport, they often need to update their Secure Identification Display Area (SIDA) authorization. This includes background checks and fingerprinting, which is an added cost for the contractors.
Distance from the spray foam roofing contractor
This shouldn’t be a surprise, but the further away you are from the contractor, the project’s price is going to increase.
Gas, wear and tear on vehicles, and hotel stays can all affect the cost of your commercial roof installation.
It’s worth noting that the most important aspect of choosing the best contractor for your job is one who installs the best, quality roof.
It would be completely un-cost-effective to choose a contractor who’s right down the road from you, yet installs a $100,000 roof that needs to be replaced in a few years.
BONUS SECTION – Renewability and future energy costs
Now that we’ve covered the cost of the installation of a spray foam roof, how do lifetime costs come into play?
The first part is that spray foam roofs are renewable.
Let’s say you get a spray foam roof with a 10-year warranty. From before, we know that 20 mils of coating will be installed over the foam roof to get you that length of warranty. In year 10, around 7-8 mils of coating will still be there.
To get a new warranty, a contractor will clean the roof, make minor repairs, and bring the 7-8 mils back to 20 mils.
It’s a very simple process that is greatly cost-effective (costs about 33% – 50% of the initial installation). When the warranty expires on other roofing systems, the roof will need to be removed and replaced (this will cost 100% of the initial installation).
The second part is about R-value and energy costs.
Spray foam has an R-value of 6.5 per inch of thickness. This is the highest R-value per inch of thickness compared to any roof insulation available.
The more R-value you have, the more heat/cool that will stay in your building and not leak through the roof. This will bring down your energy costs and lighten the load on your HVAC units.
In some situations, the cost savings after installing a spray foam roof has been high enough to equal the cost of the installation in 5 years.
In short, the spray foam roof paid for itself!
What should you do now?
Now that you know about cost, what about the other questions you might have, such as:
- What problems can spray foam roofs have?
- How does a spray foam roof compare to a single-ply roof?
- How long will a spray foam roof last?
Here are a few case studies on spray foam roofs we’ve installed:
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.