How Long Should A Commercial Flat Roof Last? & Tips for Its Longevity

Commercial | December 22, 2021  | By: John Esh

black EPDM roof installed by joyland roofing with the caption "how long does a commercial flat roof last?"

A flat roofing system on a commercial building can last 20-25 years on average3 main types of rubber roofs are installed on commercial buildings:

  • EPDM: Lifetime of 20-40 years
  • TPO: Lifetime of 20-30 years
  • PVC: Lifetime of up to 30 years

You’ll want to consider the anticipated lifetime of the roofing system you’re looking to install. Another consideration is the best fit for your building and climate.

For example, EPDM is a black rubber roofing material. It absorbs more sunlight than TPO and PVC, so it stays hotter in the summer. This could cause your cooling bill to rise.


What prevents my commercial flat roof from lasting?

A commercial roof replacement is one of the most expensive building maintenance items for a building owner. This being the case, it is of utmost importance that the roof system last at least it’s expected time frame. 


Extreme Weather 

Major storms can shorten the life of your flat roof, and unfortunately, cannot be avoided. In southcentral PA, we most often experience severe thunderstorms, hail storms, and snow storms.

If any damage occurs and it’s not repaired, you can expect the problems to worsen if not addressed.


Lack of regular maintenance 

The sad reality is that commercial roofs often fail after only 15 or 20 years due to lack of maintenance, when they could and should last 30 years or more. 

Think about that! That’s a significant loss of ROI, and a significant increase in maintenance costs over the lifetime of the building. 

Regular inspections by a commercial roofing professional will almost always save a building owner many thousands of dollars in large, expensive repairs and replacements. This is by far the best thing you can do to extend the lifetime of your roof system. 


-The math of investing in regular maintenance

Say a 10,000 Square foot roof is replaced with a warranted 20-year system. With it being warranted for 20 years, it should last 30 or more. If the roof replacement cost $8 per square foot, you would have paid $80,000. 

A regular yearly maintenance program may cost $800. This would include things like cleaning out the drains, inspecting all the penetrations and flashing points, seams, etc. It could also include a bit of caulking and patching here and there where needed. 


-What if I decline regular roof maintenance?

Now this building owner decides he doesn’t want to pay for maintenance. In year five of the new roof system, a tree branch punctures the roofing. Or maybe a careless HVAC technician drops a knife and punctures it. Whatever the case, there’s a spot for water to enter. 

With nobody doing a yearly inspection, this puncture could go a while unnoticed. What could be a quick fix can turn into an expensive repair of a larger saturated area. 

Worst-case scenario, the roof system is saturated due to multiple simple issues after 20 years. We are now needing to replace the entire system at the current market prices of $120,000.

Now suppose a yearly inspection was done for $800. Take 800 multiplied by 30 (years), and you have $24,000 in maintenance costs over 30 years. So after 30 years, you’ve paid the original $80,000, plus $24,000 maintenance for a total of $109,000. As opposed to $195,000 ($80,000 original plus $120,000 new) after 20 years. And that’s not even considering the 10-year difference! 


What kind of maintenance is required on flat roof systems?

  • Seams and Flashing Points

The roof membrane comes in rolls, typically 10’ or 20’ wide. These sheets are welded together on PVC or TPO systems, and are adhered using seam tape on EPDM systems. At all penetration points (pipes, AC unit curbs, vents, corners, etc…), the membrane must be cut to conform to the shape of the penetration.

A second layer of flashing is then required to seal around the penetration. EPDM systems use an adhesive tape to do this.

TPO and PVC systems use heat-welded seams and flashing. These bonds last the lifetime of the system, as they are welded together.  — On EPDM systems, the tape edges need to be caulked periodically to ensure that the edges don’t begin peeling off. This should happen every 5-8 years. 


  • Drains

Flat roofs collect leaves, dirt, and other debris over time. Left on the roof, this buildup will clog the roof drains. This can lead to problems such as:

-Excessive weight load from ponding water

-Water backing up into vents, pipes, and other penetrations on the roof

-Faster breakdown of seams and flashing

-Manufacturer’s warranty being void 

To avoid these problems, an annual inspection and cleaning must be performed. 


  • Puncture Repairs

It’s crazy what you’ll find on a commercial flat roof. Kids throw bottles and other sharp objects onto the roof.

HVAC technicians who service rooftop units often drop sharp objects onto the roof surface while working — knives, scissors, screws and nails. They’ll even temporarily set a new AC unit or piece of equipment on the roof with no thought of the sharp edges damaging the rooftop.

Branches break off of an overhanging tree, plunging through the roof. Regardless of the type of system on a flat roof, punctures need to be found as quickly as possible to minimize water damage to the system.

Punctures can be permanently patched with relative ease, but only if they’re found by an inspector! 


Speak with Joyland Roofing about Commercial Flat Roofing

We are local commercial roofing experts, located in Lancaster County, PA. We understand that collecting bids, comparing solutions, and ultimately selecting the best commercial roofing contractor is challenging and time-consuming.

At Joyland Roofing, we want your process to be simple and clear. You’ll never wonder what’s next in our process because of our consistent communication. Let’s chat about roofing options for your flat commercial roof.


        Pennsylvania Home Improvement Contractor License (HIC) # PA124258