Watch Your Flashing!

Written by DAVID TERRELL on . Posted in Commercial Roofing

Terrells Roofing OKCMost of the time when I’m talking with architects on new projects or property managers on reroof jobs, the conversation is about the best roof surface for the particular job.  While that is important, I want to suggest that almost as important is the flashing that is done to finish the job off.  Here’s why. All buildings settle.  Over time that settling will be more in some parts than in others.  This will cause cracking in the buildings foundation, which affects the roof envelope.  Any interruption in the roof field that is not properly flashed may open the building up to leaks.  To protect our customer’s roofing investment, we properly install flashings in each of these critical areas:
  • Wall parapets and other vertical surfaces
  • Edge details and gravel stops
  • Expansion and control joints
  • Roof penetrations.  That is, connections for vents, skylights, roof drains, and equipment
  • Water conductors:  built in gutters, alleys, and scuppers.
Flashings are the area of the roof responsible for the majority of the problems that might be encountered during the lifetime of the roof.  Flashing’s function is to provide a watertight seal between roofing materials, roof projections, and roof sections.  It should be designed to last at least as long as the materials used in the field of the roof.  In round numbers, close to 90% of leaking problems that occur do so in or around flashings.  There are several causes. Sagging refers to the condition in which the material that was used to create the flashing slides down.  This can be caused by an insufficient number of fasteners being used, too much adhesive is applied, or not enough adhesive is used. Another potential problem is seam/lap leakage.  This occurs when the joints between different types of materials allow water to enter through the seams.  Seams can also open between layers of roof materials.  Flashings in these applications should be designed to divert water away from the flashing toward a drain. The most significant source of flashing failures is post construction damage.  Activity on the roof by masons, window washers, or other workers who inadvertently kick or drop tools onto flashing can break seals.  Often this isn’t noticeable until a leak develops and water begins to enter the building. At Terrells, our commercial team is well aware of the potential breakdowns that can occur over time with flashings.  We monitor all flashing materials, installation procedures, and adhesives very carefully during the job.  We also return regularly for several months after a job is completed to double check that all flashings are performing as designed.  For any buildings where we are involved in ongoing maintenance and inspections, the flashings are a regular and important part of our work. To speak with one of our commercial roofing specialists, please call Terrell’s at 405-799-7700.