Properly designed, well installed, and regularly maintained commercial roofing systems can last in excess of 30 years. Material selection does influence a commercial roof’s service life, as material durability and weatherability vary. Immediately below is the marketed and frequently warranted life expectancy for the most often specified materials:
- TPO (Thermoplastic Polyolefin); 15-25 years
- EPDM (Ethylene Propylene Diene Terpolymer); 20-25 years
- PVC (Polyvinyl Chloride); 20-30 years
- Asphalt Roofs (Modified Bitumen & Built-up); 20-35 years
- Metal Roofs; 30-40 years
Unfortunately, due to several factors, commercial roofs regularly fail to reach their promised service life. If you are experiencing a premature commercial roofing failure there are a few likely reasons why.
Poor design decisions are a common cause of premature commercial roofing failures. These include:
- insufficient slope designed into the deck or roof insulation system, to ensure that water flows to drains, gutters or scuppers. Standing water on a roof can contribute to premature failure of the roof membrane and flashings.
- inadequate drainage capacity to handle the runoff experienced from a building’s roof can compromise any number of building envelope components including the roof system.
- incompatible building materials specified or selected.
- structural supports of the roof deck that are too weak to handle the dead and live loads experienced which can lead to excessive deck deflection, or even, catastrophic failure/collapse.
The most common cause of roofing failure is poor workmanship. Typically, issues from deficient workmanship will present early in a commercial roof’s life. This is exactly why most manufacturers require their certified contractors to cover the first two years of labor and material warranties. Therefore, if roofing issues take longer to present than the first couple of years after the installation, contractor workmanship is less likely to be the culprit.
Extreme Weather Events and Damage by Trades
Extreme weather events are more common than ever. Storms and tornadoes can cause premature roof damage due to the power of the wind that accompanies them. The damage can be from excessive uplift force or flying debris. Hail storms can also cause extensive damage to commercial roof systems. Finally, commercial roofs can, and often are, damaged by trades that are provided access to the roof such as HVAC, Electrical, and Telecommunications Contractors. It is important to remind all technicians to take care to protect the roof from work they are performing on other rooftop building equipment.
Ignored or Deferred Maintenance
There is a sound reason that every single commercial roofing system manufacturer requires that a roof be regularly maintained in order for a warranty to remain in force. During a preventive maintenance visit, many issues can be addressed and roof weathering and performance issues can be identified prior to a leak developing and the seeds of premature failure planted. The typical scope of work performed during a maintenance call includes:
- debris removal at drains, gutters, downspouts, etc. to ensure unimpeded water flow.
- deteriorated caulking repaired at penetrations, flashings, and pitch pans.
- laps, seams, and flashing details probed and inspected with identified deficiencies addressed.
- patching of cuts and holes found in the roof membrane field.
- Inspection of rooftop equipment for damage and water access points.