Estimating the Cost of a Single-Ply Roof Replacement

single ply materials on roof
A structurally secure roof is one of the most important, and expensive, components of any building. Understanding the primary factors involved in the replacement process can help business owners decide on their commercial roof replacement, including what type of replacement material to choose from and how much to budget for. 

Choose a single-ply membrane

Once you’ve decided to replace your current commercial roof with a single-ply membrane, there are two common choices: EPDM and TPO.


EPDM stands for Ethylene Propylene Diene Monomer and consists of a synthetic rubber compound. It’s flexible, durable, and has been on the market since the 1960s. EPDM costs between $1.80 - $3.50 per square foot for an average-sized commercial roof. 


TPO is the abbreviated form of Thermoplastic Polyolefin, and it’s the fastest growing commercial roofing material on the market. It’s a single layer of synthetics and reinforced scrim to cover flat roofs. TPO costs between $1.90 - $3.50 per square foot for an average-sized commercial roof.

The cost of your commercial roof replacement depends on which single ply material you choose, how thick it is, how its attached, and more.

But, we’ve drawn up a table to help estimate the cost of a commercial replacement on a 20,000 square foot roof.

Commercial Roofing Material

Cost of .045 mils thickness per sq ft

Cost of .065 mils thickness per sq ft

Ballasted TPO

$1.90 - $2.35

$2.00 - $2.50 

Fastened TPO

$2.50 - $3.00  

$2.65 - $3.15

Adhered TPO

$2.75 - $3.25

$2.85 - $3.50

Ballasted EPDM

$1.80 - $2.25

$2.00 - $2.35

Fastened EPDM

$2.00 - $2.25

$2.20 - $2.70

Adhered EPDM

$2.80 - $3.20

$3.00 - $3.50

Prepare your current roof

The current condition of your roof is a crucial aspect in determining the cost of a new commercial roof.

There are 3 options when dealing with the existing roof:

1. Clean and prepare the existing roof

If your current commercial roof is free of large problems and doesn’t require major corrections, the contractor will only need to clean and prepare the roof. There are four ways a contractor typically prepares a roof for single-ply installations: 

  • Powerwashing

  • Dry vac/ballast removal

  • Wet vac

  • Air pressure cleaning

Cost: $.10 - $.75 per square foot

2. Fasten recovery board on top of the existing roof

Recovery boards are used to cover and improve the application surface. This process is used to cover joints and provide a separation layer between the existing and new roof system. 

Cost: $.70 - $1.40 per square foot

3. Strip and remove the roof

Stripping and removing the old roofing material is one of the more costly options before installing a new single ply system, but it may be necessary for a proper installation. Additionally, a building can’t have more than two roofing systems. So, if you currently have two roofs installed over one another, the contractor needs to remove them before installation can begin.

Cost: $1.00 - $2.00 per square foot


Account for insulation

commercial roof insulation

After the roof is prepared for the replacement, the insulation is installed. Most contractors install two layers of insulation. There are three options commonly used: Polyisocyanurate (Polyiso), Expanded Polystyrene (EPS), and Extruded Polystyrene (XPS).

Polyiso is the most popular option. It can be cut to size, has a longer lifespan, and is installed in either 1-inch, 2-inch, or 3-inch thicknesses.

The following costs include labor and material for installing Polyiso:

  • 1 inch: $1.40 - $1.75 per square foot 

  • 2 inch: $2.00 - $2.50 per square foot

  • 3 inch: $2.80 - $3.15 per square foot


Consider accessibility and other cost factors

The condition of your current roof is perhaps the biggest factor in calculating the cost of a new single-ply membrane roof. If your roof is dangerous to walk on, or is sloped and difficult to access, additional costs will occur. The more limited the access to the roof is, the more expensive it will be.

The roof’s height and distance from the ground can multiply the cost of the commercial replacement.

Sloped and steep roofs require scissor lifts and/or repelling gear. Furthermore, contractors may need to rent equipment, such as cranes or hoists, to move the crew and materials.

In addition, many other factors impact the costs of replacing a commercial roof, including:

  • Planning and moving equipment up to and across a large roof

  • Material transport

  • Debris removal

  • Condition of the existing roof

Economies of scale for commercial roofing start around the 20,000 square feet mark. In other words: The bigger the roof, the lower the per-unit cost will be for the roofing materials. This means business owners can start saving money after this benchmark.

At Hometown Roofing Contractors, we'll help you find the right commercial roofing contractor. Customers can see which roofers have experience with single-ply materials, see what other customers have to say about their services, and request multiple quotes.

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