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How to Repair a Flat Roof

Roofer applying roofing felt to flat roof

Flat roofs are becoming more and more popular for both ultra-modern homes and commercial buildings. However, flat roofs can harbor more water and debris than sloped roofs, making them slightly more prone to leaks. If you suspect your flat roof has a leak, read on to learn the basics of how to repair a flat roof. Then, reach out to a roofing professional who can assess your roof and make the necessary repairs.

How to Repair a Flat Roof

Step One: Locate the Leak

Your roofer will typically begin by locating the leak, often beginning from the inside of the home. That might involve using any visible potential leaks – areas with clear water damage, for example – as starting points. Your roofer will likely then scour your roof for any noticeable punctures, seam separations, blisters, and other membrane issues. Finally, they may examine your vent pipe boots, flashing, or vent caulk for further damage.

Step Two: Determine the Severity of the Leak

After your roofer identifies the leak in your roof, they will determine the type and severity of the leak. The assessment will inform their repair strategy. The following are common issues:

  • Small holes: Your roofer can likely repair minor damage quickly and relatively cheaply. This process might involve applying rubber sealant or a peel-and-stick flashing patch.
  • Membrane blisters: Blisters in your roof membrane may require a more thorough repair strategy. Your roofer will likely cut through the bubble formed on the membrane before using towels or a propane torch to dry the affected area. Then, your roofer will repair the material with roof cement, tar, or a peel-and-stick flashing patch. Some roofers may also secure the blister flaps with roofing nails.
  • Large rips and tears: Large damaged areas require an intensive repair strategy. Expect your roofer to remove damaged materials, creating a clean and dry surface for the patch. They will likely apply new rolls of membrane, which may or may not involve heavy-duty equipment like a crane. From there, your roofer will cover the seams between the old and new roofing materials with a specialty leak-proof seam tape.

Roof Repair vs. Roof Replacement

Make sure to work with a professional to determine if your flat roof requires a repair or a complete replacement. Failing to effectively treat the leak can result in thousands of dollars wasted. For this reason, we discourage DIY repairs on flat roofs. While experienced DIYers may have the right tools and materials to repair a flat roof, failure to repair a roof correctly can be catastrophic. Repairing an old, leaky roof is also likely a waste of money. Ultimately, flat roofs start to leak after about 12 to 15 years, and replacement is typically the only option at that point.


Flat roofs work well on both modern homes and commercial buildings, but they do need to be inspected regularly so that minor problems don’t grow into costly issues. Now that you’ve reviewed the basics of how to repair a flat roof, you know what to expect when you reach out to a professional. 

If you live in southwest Missouri, contact Taylor-Made Roofing for help. Our experts can help you explore flat roofing options, maintain an older roof, perform emergency repairs, complete tear-offs and recovers, and perform remodeling services. With over 20 years of experience in residential and commercial roofing, Taylor-Made Roofing is a company that you can trust with all of your roofing needs. Our family-owned business offers quality services, a reassuring warranty, and free estimates. For more information regarding roofing options, please give us a call at 417-326-8778 or contact us online. We look forward to hearing from you!

Fully licensed and insured, Taylor-Made Roofing is ready to take care of your roof.
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