Four Common BUR Asphalt Roof Leak Sources

The way an asphalt roof wears — the bumps and wrinkles it bears — can show a lot about why it is failing. Each type of failure — blisters, splits, and punctures — typically results from a specific cause. Poor design, for example, can lead to splits and debris can cause punctures. Understanding the causes of the most common types of roofing problems can help facility executives prevent the errors that too often shorten the life of the roof.

1. Blisters. Bubble-like or long, thin raised areas on the roof are called blisters.They occur when a gas, usually water vapor, is trapped within the roofing system either between the plies or between the plies and the insulation. The heat of the sun during the day causes the gas to expand. The expansion of the gas creates a pressure within the system that pushes the plies apart, resulting in the blister.

Blisters would not occur if there were not some reason for moisture in the membrane. Two common causes are applying the roof to a damp substrate, as during a re-cover, and applying wet materials, such as felts, that have absorbed dew or rain on the edges. The moisture that causes blisters can often be traced back to another problem: improper storage of insulation which allows water to soak through holes in shrink wrap or at the bottom of the stack where shrink wrap doesn’t cover. Moisture can also get into a roof installed in the presence of rain or dew.

2. Splitting. The most common splits occur when a metal accessory is flashed with a membrane material. As the temperature changes, metals and membranes expand and contract at very different rates. Because the membrane generally cannot move as much as the metal, it will eventually fatigue and crack when it is adhered to metal. This problem is not as common with single-ply membranes being there is better expansion and contraction capabilities, but it is common in asphalt systems. Splits are not limited to flashings, however. As most roofs age, they become more brittle and less resilient. This means that they become less resistant to movement from common sources such as temperature changes, foot traffic, and substrate movement. Because the roof cannot flex or stretch as well as it did when new, it cracks.

3. Punctures. The most preventable failure symptom, punctures, usually occur because of carelessness on the part of people visiting the roof: HVAC technicians, window washers, painters, maintenance staff, smokers, and tenants. Punctures can also occur because of debris left, blown, or tossed on the roof. They may appear as tears or holes and allow direct water intrusion. Since Tropical Storm Debby, RAMCON has repaired more than 637 punctures to roofs, 99% of which were preventable.

Chances are, if you have a Built-Up, Asphalt or Modified Bitumen roofing system, you have experienced some (if not all) of these issues. Give us a call and we’ll perform a detailed, thorough review of your roofing system at no expense and make sure your roof is ready to battle Mother Nature.