life time cost of a commercial roof

4 Factors That Influence Life Time Cost of a Roofing System

Greg PalyaBuilt-Up Roofing, Metal Roofing, Single-Ply Membrane Roofing, Spray Polyurethane Foam Roofing

Choosing which type of roofing system to install over your existing roof can be a daunting task. You know the roof is going to cost a lot of money regardless of which system you choose.

Cost is the #1 influence in the purchasing decisions we make: regardless if it’s a roof, bubble gum, or a new car.

But instead of choosing a roofing system solely on initial price, what if we looked at the bigger picture and analyzed life time cost?

Or maybe it’s worth considering what would happen if you wanted to sell this building one day?

Selling a building with a renewable roofing system, as opposed to a roof that needs completely torn off and replaced every 10 years, certainly increases the value of that building.

In this article, we’re going to look at the initial cost of commercial roofing systems, as well as other factors that influence life-time cost, such as:

  • R-value
  • Renewability
  • Value of the building

At West Roofing Systems, we’ve been installing, repairing, restoring, and servicing all types of commercial roofing systems since 1979.

Let’s dig into the factors that influence the lifetime cost of a roofing system…

1. What are the approximate initial costs of different roofing systems?

Here are the most popular commercial roofing systems and their approximate price per square foot:

NOTE: these prices are ballpark, meaning there are MANY variables that can shift the price to either side of the range.

What variables can influence a commercial roofing price?

Roof Attachment – What kind of decking does your building have? Say you have a concrete deck. To install a single-ply system, you’ll need to fasten your insulation and single-ply sheets to that concrete deck, which is expensive and difficult to do. On the other hand, a spray foam roof can be sprayed directly over the concrete and eliminate all the labor and difficulty with fastening.

Location – A roofing contractor that does metal roofing (most expensive) might be cheaper than an EPDM roof (cheapest) if the metal roofing company is 2 miles from your facility and the EPDM roofer is 150 miles away.

Penetrations – if you have a roof with only a few penetrations, a roofing system that can be installed with rolled out material will have little interruption, which reduces labor costs. A roof with pipes, drains, HVAC units, exhausts, and other penetrations makes the labor difficult for rolled roofs since the sheets will need to be custom cut. A spray foam roof can be sprayed around penetrations, which reduces the time the project takes.

Worker skill – a roofing contractor that’s brand new will have newer roofers which have lower labor costs. A roofing contractor that’s been in the game for 40 years, will most likely have installers with 10, 20, or 30 years’ experience. These roofers get paid more, but their performance makes up for it. On your 20,000 sq. ft. roof that you’ll spend $100K on, it’s beneficial to the long-term performance of the roof if it’s installed by experienced roofers.

These are just a few variables that can impact price.

Word of advice: Don’t worry about the ballpark costs with each system. With all the other variables involved, your best option is to get a few quotes from contractors doing different roofing systems, and then weigh all the pros and cons each roofing system provides.

One way a roofing system can provide value over other systems is through its R-value.

2. What’s the R-value of different roofing systems?

If you’re unfamiliar with R-value, it’s a material’s ability to resist thermal movement through it. The higher the R-value, the more insulation that material provides.

A stronger insulation reduces the amount of heat/cool that escapes through your building’s roof, therefore lowering your energy bills.

Here are the R-values of the most popular commercial roofing systems:

  • Spray Polyurethane Foam: 6.6 per inch of thickness
  • Metal: 0.00 per inch of thickness
  • TPO: 0.24 per inch of thickness
  • EPDM: 0.33 per inch of thickness
  • BUR Gravel: 0.34 per inch of thickness
  • BUR Smooth: 0.24 per inch of thickness
  • XPS Insulation: 5.0 per inch of thickness
  • EPS Insulation: 3.85 per inch of thickness
  • Polyiso: 5.5 per inch of thickness

A spray foam roof can pay for itself through energy savings in 5-10 years. The amount of time it takes to recoup the investment relies on a few factors, such as:

  • How much R-value does your current roofing system have?
  • How often do you run your HVAC units?
  • How energy efficient are your HVAC units?

If we’re talking about life-time cost of a roofing system, in essentially 10 years, a single-ply roof might need to be completely removed and installed with new material.

With a spray foam roof recouping it’s cost over 10 years, the life-time cost is zero.

But what happens after year 10?

3. What’s the renewability of different roofing systems?

After year 10, 15, or 20 (however long your roof warranty is), what happens next?

On most roofing systems, you need to remove them completely, transport all the materials to a landfill, and then re-install the system from scratch.

One roofing system that stands out is spray foam.

The reason is that it’s a renewable roofing system.


The initial application is usually 1.5” – 2” of spray foam, 20-30 mils of silicone coating, which is either rolled or spray-applied in two separate coats, and then granules are embedded into the topcoat of coating.

After year 10, the initial 20 mils of coating might be down to 5-8 mils.

To renew the roof, all that needs to be done is to make minor repairs (if any), which is done by cutting around a small hole, drying the area, and filling it with silicone coating or caulk.

Smooth out the area and you’re done.

Once these are done, a roofing contractor will install coating and granules at the original measurements. This process is called a “recoat” and generally costs ½ to 1/3 of the original installation.

A renewable roof system is great, but I’m not living forever. What happens if I want to sell this building one day?

4. How does the current roof system affect resale value?

Whether you’re looking to buy a building or you’re selling one, the current roof condition can greatly affect the value of the building.

Think about it:

Would you want to buy a building that just had the roof re-done last year? Heck yea!

Would you want to buy a building whose roof is 20 years old and currently leaks? Heck no!

If everything else was exactly the same, do you think those two buildings would be the same price?

Absolutely not. An average price for a commercial roof is around $5 per sq. ft. If that roof is 20,000 sq. ft., that’s $100,000.

If an adjuster or building inspector determines the roof has approximately one year of life left, you could expect the value of the building to decrease by around 100K.

This is why it’s important to think about how the roof you install today can help, or hurt you financially down the road.

Would you rather purchase a building that I know I’ll need to completely remove and replace someday, or one that can be renewed over and over again at a fraction of the original installation?

NOTE: Some spray foam contractors allow the warranty to be transferred to the new owner. Bonus selling point!

Comparing commercial roofing systems

Hopefully today you learned that there’s more to consider than just the initial cost of a roofing system.

What should you do next?

If you think you need a roof installed or repaired, go to Google and jot down a few local roofing contractors. See what kind of roofing systems they can install and jot those down as well.

If you’re within 150 miles of any of West Roofing Systems locations, we’d love to be one to give you a spray foam roofing quote.

And if you’d like to educate yourself further on spray foam roofing (because it’s the lowest lifetime cost roofing system available), please view our Ultimate Guide to Spray Foam Roofing.

the ultimate guide to spray foam roofing

About the Author

Greg Palya

Greg Palya is the Digital Content Manager of West Roofing Systems, Inc. He has a B.S. in Marketing from the University of Akron and an MBA in Marketing from Walsh University. When he's not trying to teach others about spray foam roofing and silicone roof coatings, you can find him on the basketball court or golf course.