Many elements of a flat roof present leak potential if they were installed improperly or because the system is aging out. When your commercial flat roof fails at its job, you have to take time out of your busy schedule to find the source of the leaks. Worse, you may need a whole new roof, news that few building owners want to hear. What could cause the leaks?
If the roof was built without enough of a pitch to let water flow quickly to the drains — or building settlement has altered the pitch — it will pool up in places. Standing water can eat away at asphalt-based roof systems, especially at the seams.
Even membranes impervious to standing water can develop weak seams over time. Sun, wind and hail do their utmost to pull apart exhausted overlaps.
Punctures in Membrane
Wind-borne debris and too much foot traffic can puncture a membrane roof. Dropped tools, gravel stuck in boot treads and flying tree limbs can cut into EPDM, TPO, PVC and APP (modified bitumen) cap sheets.
Cracks in Tar
Built-up, or tar and gravel, roofs tend to develop cracks when the roof has seen better days. If most of the gravel has shifted to the perimeter of the roof, the tar takes a heavy UV assault and dries out. Shrinking as it dries, crevasses open up and let water in.
Parapet Walls and Cap Metal
Many flat roofs have a parapet wall. Membranes run up the walls, and coping metal covers the exposed edges. Wind can dislodge the metal, allowing rain to work its way between the membrane and the wall.
In some building designs, the parapet walls are stuccoed with the rest of the exterior. If the stucco cracks, it can allow water penetration, which, technically, isn't a roof leak. These types of leaks can be tough to diagnose.
HVAC Units and Other Protrusions
Making your heating, ventilation and air conditioning units watertight where the vents and electrical lines run down into the building requires quite a few careful laps and small membrane pieces. Any of these can shrink and pull away as the roof ages. Occasionally, HVAC units can take on water inside and rust out the pan that should prevent leaking.
If the drains that should keep water flowing off the roof get plugged with leaves and dirt, the water can back up and create a pooling situation. When the drain system includes openings in the parapet wall (scuppers) with exterior downspouts, the water backed up in the downspout can seep under the roof's waterproofing system at the outside edge of the scupper.
If your commercial roof begins to leak, you need flat roof specialists. We have the expertise to troubleshoot leaks and make lasting repairs to serviceable roofs. If a new roof can't be avoided, we'll go over all your options and help you find the best solution to fit your goals and budget. Call us at MG Roofing, Inc. today to get started.