How to Prevent Your Commercial Roof from Failing Prematurely

How Long Do Commercial Roofs Last?

Roof performance isn’t usually a building owner’s priority until a leak appears or the roofing system is near the end of its lifespan. While materials play a role in how long a roof lasts, the choices made throughout the roof’s life have far more influence than many realize.

Most commercial roofs last between 15 and 25 years, though real-world longevity is influenced by material selection, installation quality, maintenance and climate conditions. With the wrong materials and poor installation quality, a roof’s useful life might be 10 years. In the right climate, a well-installed and well-maintained roof might last 50 years. Understanding how these elements work together can help building owners protect their investment and extend the useful life of their roof.

Factors That Impact Commercial Roof Longevity

A roof’s lifespan isn’t solely determined at installation: it’s shaped by every decision made afterward. From routine inspections to the proficiency of repairs, each factor influences whether the roof meets its expected lifespan or becomes a liability years earlier than expected.

Maintenance

Annual or biannual inspections catch minor issues before they escalate into costly failures. For example, a simple roof drain: a single uncleared drain collects leaves, which trap standing water. Over time, that water backs up onto the field of the roof, seeping into seams and ponding in low areas. What could have been solved with a brief cleaning led to trapped moisture, seam degradation, interior leaks, and substrate damage. Regular maintenance will save you money and reduce the chance of premature roof failure.

Installation

Even with premium ingredients, a bad baker will still make inedible bread. For a commercial roof, great products installed poorly results in a vulnerable roof. Let’s examine flashing. If flashing around a skylight curb is misaligned, it only takes one storm-driven rain to expose it. Water infiltrates seams in the membrane, saturating the insulation. Trapped moisture can deteriorate the deck itself, incurring additional expenses when the roof requires replacement. Proper installation, especially at seams and transitions, is a prerequisite for a long-lasting roof.

Wind Uplift

Hail and the gauntlet of seasons in the lower Midwest challenges all roofs. But an overlooked factor is wind exposure. At ground level, the ground and trees slow the wind – a phenomenon called the boundary layer effect. 30 feet above ground level, with no natural windbreaks, the wind accelerates dramatically. This force is called the wind gradient. As the wind blows over the roof, it creates suction at perimeter edges that begin to peel the membrane away from the substrate. Without proper fastening, these uplift pressures exploit weak points. In the lower Midwest, where most buildings are fully exposed, roofing experts account for increased perimeter fastening demands to prevent premature edge failure.

Improper Repairs

During an HVAC contractor’s regular service, a tool might get dropped or a panel might get dragged. These mishaps are inevitable, and the small punctures they produce can be patched quickly on a TPO roof. If the patch is performed without inspecting whether moisture has entered the substrate, any moisture will be trapped. That moisture will get wicked into the insulation, saturating it. These minor punctures are nearly inevitable on roofs with frequent foot traffic. Routine maintenance fixes what’s visible and potentially what’s underneath by inspecting for underlying moisture and obscured damages.

Roof Types and Their Lifespans

Below are the average lifespans of common low-slope roof types.

• TPO
  • TPO was introduced in the 1990s as a means of combining the flexibility of EPDM with the heat-weldable seams of PVC. This effort was a success, as it’s our most-installed roof membrane and is generally considered the industry standard. Its average lifespan is 15-25 years.
• Modified Bitumen (Mod Bit)
  • Modern Mod Bit was developed in the 1960s and 70s, but bitumen has been used for waterproofing for over 5,000 years. Ancient Mesopotamians used natural bitumen to seal boats and waterproof buildings. Today, it’s combined with modern polymers to create Mod Bit. Its average lifespan is 15-20 years.
• EPDM
  • EPDM gained popularity in the 1970s when the oil embargo in the Middle East raised the price of asphalt roofing products that were common in the ubiquitous BURs at the time. Its average lifespan ranges from 15-30 years.
• PVC
  • PVC is exceptionally resistant to chemicals. It can be directly exposed to jet fuel without immediately degrading, making it useful for airports. Its average lifespan is 15-25 years.
• Built-Up Roof (BUR)
  • Until the 1970s when single-ply membranes became standard, BUR was the dominant low-slope roofing system in the United States. While it’s durable, its traditional installation is labor-intensive and requires hot tar. Labor costs have increased, and single-ply membranes have become viable, leaving BUR as a niche system. Its average lifespan ranges from 20-30 years.

Proactive vs. Reactive Maintenance: Real-World Example

A commercial roof’s lifespan can’t be guaranteed, but a roof’s maintenance determines whether it reaches or even exceeds its expected lifespan. In 2012, the Air National Guard conducted a case study comparing reactive maintenance (repairs made after damage occurs) to proactive maintenance (routine inspections and preventative care.)

Commercial roofs maintained reactively lasted an average of 13 years; roofs with a proactive maintenance plan averaged 21 years – extending the roof’s lifespan by over 60 percent.

Regular oil changes are preventative maintenance. Waiting to change oil until the engine goes out is reactive maintenance. Replacing an engine is significantly more expensive than a few quarts of oil, and a new roof is no different.

At an average replacement cost of ~$60,000 for a 10,000 square-foot roof, the difference between replacing a roof every 13 years versus every 21 years is tens of thousands of dollars saved over the life of a building.

Proactive maintenance programs identify minor issues that can be resolved before they escalate into costly damage. Regular inspections that provide proper documentation, along with proactive repairs, allow building owners to extend their roof’s life well beyond its warranty period. A proactive maintenance plan that’s tailored to your roof and building conditions helps avoid unexpected expenses while maximizing the value of your investment.