9 Proven Flat Roof Leak Repair Tips

Emergency Roof Leak Repair

Flat roofs carry their own set of challenges, and it is just something that commercial building owners have to watch out for. Fortunately, in Southern California, rain is not as much of a problem as in other parts of the country. Still, good building maintenance requires a close inspection of roof systems so that you can be quick to respond when a flat roof leak repair is needed. Here are some tips that can prove helpful when a leak repair is warranted.


1. Addressing the Roof Type

You need to figure out what type of roofing system your building currently has so that you will know what material will be needed to fix it. Remember, if the flat roof is significantly damaged with a lot of leaks, you should be considering a larger solution. But if a patch job seems to be within your realm of capabilities, here is what you should know.

• EPDM (rubber) roofs: Supplies for rubber roof repairs, such as flashing, seam tape and glue, usually must be purchased from a roofing contractor rather than just a home improvement store. You can make repairs with rubber glue or peel-and-stick patches.

• Tar and gravel roofs: The hard part about leaks on these roofs is that they are difficult to trace. Once you find the problem area, just patch the spot with tar, mesh, and more gravel.

• Fiberglass roofs: Problem areas for these roofs include flashings and cracks due to expansion or contraction. Acrylic sealants are good for quick fixes, but a more permanent solution involves sanding the area, laminating a chopped strand mat into place, and letting it cure.

• Asphalt roofs: These are pretty durable, but a crack might need a paint-on barrier or, for a more significant problem, try fixing it with a layered-on patch or a liquid patching system.

2. Locate the Leak

Look for the source of your leak from inside the building. The water may have run along your roof through the leak and pooled in a different spot, meaning the leak may not be the spot that has the most water. Take a few measurements of the area where you suspect a leak relative to nearby walls. 


3. Examine The Roof

Take the measurements you made from the interior and begin looking for the leak on the roof. If no damage is apparent, look for any damage to the roof membrane near any flashing or vents on the roof. If you have to use a ladder to access the roof, make sure it is securely positioned on the ground. If your roof is too high or you feel unsafe, or if you simply cannot find the leak, you may need to call a specialist.

4. Remove Any Debris

Your roof may have debris that can obstruct your work or which can cause further damage. Carefully remove any foreign objects from the area near the roof leak before starting work. You’ll also be able to determine if your roof was damaged in a storm or if it is simply facing age-related wear and tear.

5. Dry the Area

Flat roofs often collect water, so be sure to dry the area you intend to repair before you begin to work on it. If you repair a hole and trap moisture underneath your patch, you could cause mold to grow under your roof. If large amounts of water are already running in between layers of your roof, you may need professional assistance.

6. Identify the Damage

Look for any blisters on your roof, which can indicate that water or air has seeped between the different layers of your roof. You will also want to check for cracks or alligatoring, which usually indicates long-term sun damage. The type of damage you have will determine which repair method is most appropriate. In cases of severe damage, it’s best to call a professional.


7. Cut the Damaged Area

If your roof leak is due to a blister, carefully cut through the damaged membrane and remove any moisture that may be present. You’ll need to cut away all damaged layers of your roof membrane, but be careful to not damage the roofing felt underneath. Make sure to thoroughly dry the areas you want to repair before moving on to the next step.

8. Apply Roofing Cement

Peel back the layers of the membrane you cut and apply roofing cement to the leak and to the entire section of the roof underneath the membranes you cut away. This will plug it and will also provide an adhesive for the flaps of the membrane to stick to. Press the membrane flaps to the cement to reseal the cut.

9. Nail it Down

Once you lay down the flaps of the blister, nail them to the roof to fully secure them in place and to seal the leak. Make sure you won’t be nailing any wires underneath or any other sensitive infrastructure. Cover the nails with more roofing cement to seal any holes you may create.



It can be very tricky to find the actual source of a roof leak. So if you don’t feel like taking these steps yourself you could contact a professional commercial roofing company that specializes in flat roofs. They should be able to assess your flat roof and provide you with a free estimate running down all your options to repair the stubborn roof leak. 

Though it doesn’t rain frequently in Los Angeles, the occasional downpours can unearth unseen or neglected leaks in your flat roof. It is difficult to pinpoint and address every leak. However, with regular flat roof maintenance, you can spot damaged areas on your roof before they become major problems. A complete flat roof replacement should be the last option after temporarily patching the leak or contacting a professional roofing company.

Central Roofing Company also provides professional application of acrylic and silicone roof coatings at a reasonable cost. Our expert roofing technicians are continuously trained on the most recent technological advances in materials and application techniques to provide the best service possible.

Instead of throwing away time and money with continuous, temporary flat roof repairs, let the professionals at Central Roofing Company install a long-lasting flat roof coating or conduct other repair services. Contact us today to learn what is best for your roof and how to best protect your roof against leaks.


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