My Roof is Leaking!
“Help! My commercial roof is leaking!” As leaders in the silicone roof coating industry, we get this call quite often! Thanks to our nationwide network of Certified Licensed Applicators (CLAs), we can typically offer a solution pretty quickly. If, however, you want to do some troubleshooting on your own before calling a contractor, this article is for you. We will go through each roof substrate and discuss some common issues that could lead to a commercial roof leak. This article works as a complement to our roof inspection checklist found here. Between these two pieces, you should be able to address any roof leaks with much more knowledge.
Note: Since ponding water is a potential problem for all flat roofs, we won’t be going in depth about it for every substrate. The flatter the roof, the higher the chance that water will find a low area and begins ponding. Standing water becomes a problem if it’s still there 2 days after the last rainfall. If you already have ponding water on your roof, reach out to your Regional Manager and they can connect you with one of our certified contractors!
Roof Leaks on Single Ply and EPDM Membranes
Single Ply substrates are easily susceptible to tears and punctures. And as with all seamed substrates, they are prone to damage at the seams. Comprehensive inspections throughout the year should be able to catch serious damage before it occurs, but this is not always the case. Additionally, when work is done on the roof (servicing HVAC units or skylights, etc.), damage can occur. To assess possible damage to your single ply roof, first look for failed seams.
On a very aged system, you may also find scrim showing through. This is especially common on EPDM roofs and is typically caused by shrinkage. Shrinkage comes from the expansion and contraction of the substrate which can pull away from the flashings at curbs, parapet walls, and penetrations. Ultimately, these cracks will allow moisture in.
Another concern with almost all flat roofs including TPO/PVC/EPDM is hail damage. PVC and TPO can withstand hailstone impact up to 1 ¾ inches in diameter. But, if you have an aged TPO/PVC membrane, even smaller hailstones could cause fractures. An EPDM roof in fairly good condition can withstand hailstones up to 2 ½” in diameter since it is a flexible thermoplastic membrane. No matter the membrane, however, be sure to inspect your roof for damage after every major hailstorm to ensure there are no punctures that could allow water into your building.
Roof Leaks on Modified-Bitumen Roofs and BUR
Roofing Contractor Magazine outlines some common points of concern for mod-bit substrates: “In bituminous systems, voids can be created by improper adhesion during application, improper mopping viscosity, moisture in or on the felts, unfilled insulation joints, coverage of loose or trapped material particles, and distorted insulation or metal materials.” In other words, there are a lot of pieces that comprise mod-bit and BUR substrates so there are more things during installation that can go awry.
Along with the normal issues found on roofs with seams, BUR substrates are prone to alligatoring and cracks due to shrinkage caused by the UV rays. If you notice alligatoring on your roof, don’t fret. Our SL 800 Surface Leveling Coating is designed specifically for roofs with unusual surfaces. This low-cost silicone goes on thick, before the topcoat to ensure a watertight and seamless PM Silicone topcoat.
When performing inspections or repairs on your roof, make sure you keep safety in mind. Some roof substrates are very slick when they are wet so be sure to wear non-slip shoes and inspect the roof for wet spots before beginning the inspection. Make sure to also keep an eye out for skylights on the roof. If the roof has non-raised skylights, you can fall through them if not careful. If your roof does not have parapet walls, make sure you are staying at least 6 feet from the edge if you do not have a harness system on. There are countless safety issues to keep in mind when inspecting a roof.
Always make sure to abide by OSHA standards when on a roof to ensure your safety. For more safety guidelines, you can find our Roof Safety Checklist here. For more questions you can contact your Regional Manager who can have a CLA come out and look at your roof for you.
Whether it’s trouble with a leaky roof or questions about restoring your roof we are here to help! Call our office at 812.944.7803 and you can speak directly to a technical director or get connected to your local PM Regional Manager. In part two of this series, we will be discussing roof leaks on metal and spray foam substrates and some other common causes of water in the building. You can find that blog here.