Why Commercial Roofs Fail

May 18th, 2017


Roofs fail for three primary reasons.

1.Improper Materials
Generally this is the least common reason for failure. Most roofs are installed with proper materials that are specified by an architect, roofing consultant, roofing manufacturer, or qualified roofing contractor.  There are instances where improper materials are the reason for failure. Most often improper materials are installed when an inexperienced building owner “researches” roofing products himself.  It is commonplace to find a building owner contacting “sales motivated representatives” of second or third tier manufacturers who specialize in marketing… and who are limited to the range of products that they offer to sell.  For example there are many coating manufacturers who market “miracles” in a can. Owners are told that this product can be applied over almost any substrate and ultimately fix a leaking roof long term.  Most times the product is overpriced and at best provides a temporary solution to the problem.

2.Improper Installation
Not all roofing contractors offer the same level of experience, installation quality, or business ethics. For the most part, when the proper materials for the roofing project are specified, the finished quality of the actual roofing installation does range considerably between contractors. There are many variables that affect the quality of the roofing installation.

  • Weather is a daily concern in almost every roofing project…and roofing decisions based on weather forecasts are made daily. These decisions can have a dramatic effect on the finished roof quality. Moisture entrapment created during construction of the roof is a leading cause of premature roof failure.
  • Detailing…how a contractor performs various small, but extremely important “flashing” details… are ultimately critical in making the roof weathertight. Many times this important detailing is often overlooked or not really understood. Many important roof details can be missed or treated with “short cuts” and their mistreatment over the life of the roof creates a premature roof failure.
  • Integration of building components like HVAC units, roof drains, vents, windows, roof slopes, parapet walls, changes in building elevations, stairs or pathways of access, exposures to wind or potential wind damage; each can independently affect or cumulatively combine to affect the performance of the roof and cause premature roof failure.

3.Improper Owner Maintenance
The environment in which a roof is placed is incredibly dynamic.  The effects of wind, rain, ice and snow, extremes in temperature, etc. all put stresses on the waterproofing capability of every roof almost every day.

Winds can damage not only the roof’s attachment to the building, but wind borne objects like panels blown from HVAC equipment, limbs from trees, stored pallets or equipment on the roof are all potential objects that commonly damage roofs.

Weather Conditions

Rain continually tests the roofing water tightness.  Factor in tree seeds, autumn leaves, and other organic debris that often end up clogging roof drains or gutters…and the problem is exacerbated. When drains are not free flowing, water floods the roof surface and rises above flashing heights and causes water entry and severe leaking.

Ice and snow build up on roofs adding significant loading of the structure. Movement of this ice and snow on the roof damages roof flashings, pushes equipment off its curbing, and scours the roof surface.

Extremes in temperature occur annually. Brutal heat and frigid cold put extreme stresses on the materials that comprise a roof system.  Less understood… we experience 75-100 freeze-thaw cycles (FTC) annually.  The effects of this freeze-thaw activity is most vividly seen and experienced in the destruction of our paved roads in the manner of “pot holes.”  Roofs too experience similar damage inherent in freeze-thaw cycling.  However, the damage to the roof is almost microscopic in size compared to the visible damage done to pavement.  The resulting damage to a roof created by the (FTC) is manifested in blistering, splitting, and tearing…all of which can allow great amounts of water to enter the roofing system…and the building.

All four of the above “elements” in weather are reasons enough for any building owner to be constantly vigilant as to what is happening on his roof.

Besides the “natural” deterioration that a roof faces due to the elements there are occupant created issues. A myriad of leaking develops on roofs from foot traffic, roof top equipment servicing, window washing, equipment additions, new venting through the roof, additions of safety equipment, sky lighting, and solar installations…none of which is directly related to the intended performance of a roof.

Unfortunately what is “out of sight”…is most often “out of mind.”  Areas of the roof that are weathering or experiencing incremental damage often are ignored and nothing is done to correct the small problems.  It is not until the small problems become large and increasingly inconvenient that anything is done.  Then …all too often…the inspection and repair is done by someone other than a roofing professional trained to survey, detect, and repair “typical” problems that exist on almost every roof to some extent.

In general, lack of attention and maintenance of a roof is very often the precipitous cause of the majority roof failures.  It is an unequivocal fact that a well maintained roof will enable a typical roof to last longer—and on average, the life of a roof can be extended 25% longer through regular maintenance.