How To Identify, Prepare, And Repair A Leak In Your Flat Tar And Gravel Roof

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If your commercial building has a flat tar and gravel roof, making repairs and maintaining the roof can be a simple process for you to handle by yourself. Unfortunately, this type of roof is also more likely to acquire leaks. Here are some instructions to help you identify, prepare, and repair a leak in your flat commercial building roof.

Locate the Leak

To locate a leaking area on your flat tar and gravel roof, there are many clues you can look for around the surface of the roof. A leak inside your building may not always indicate where on your roof the leak is originating from, as the leaking water can come through your roofing material, then travel a distance between the materials and appear inside as a leak in a different spot. 

It can be easiest to look for low sloping areas on your flat roof, which will allow water to pool and could indicate an area where the water is entering. As water collects in the lowest spot of your roof, it is not draining from your roof properly and can lead to a leak. Siphon up as much of the water with a shop vac or other water pump, or mop up the water with some old towels. Once the water has been removed, you can inspect the area for the water leak's entry spot.

Besides keeping your business cool in the summer and warm in the winter, the gravel layer of your roof protects the underlayment of bitumen and tar. If an area on your roof is missing gravel, the sun and weather can damage the exposed roofing layers and lead to leaks, so check any gravel-free areas for any cracking, peeling, bubbles, or other type of damage.

If you have not found the source of your leak, use a rake or a broom to sweep aside as much gravel as possible to check other areas of your roof. Look for any areas where the roofing material is showing signs of damage.

Prepare the Area

Once you have determined where the water is leaking into your building's roof, you can prepare the damaged section for repair. First, rake or sweep away any loose gravel, if you have not already done so.

Clean the surface area around the damage with a wet cloth to remove any dirt and debris that can prevent your repair patch from adhering. If you are dealing with a bubble in your roofing, cut an X into the roofing layer to open up the bubble. Mop up any water inside the bubble and wipe off any dust and dirt inside and on the outside of the damaged area. Open the cut X to allow the inside of the X to dry completely.

Coat primer over the damaged section with a brush to prepare the area. The primer adds necessary oils back onto the roofing membrane to help it accept patching compound more successfully.

Repair the Leak

Now you can complete the repair and patch the leaking roof section. To repair inside a roofing bubble, apply roofing cement into the bubble pocket and press the opening to the bubble closed. Apply an additional layer of roofing cement over the top of the X-cut and extending approximately two inches beyond the edges of the cuts.

If you are repairing a hole in the roofing membrane without a bubble, cut a piece of roofing material two inches larger than the hole to create a patch. Apply roofing cement over the hole and two inches around it, then press the patch onto the repair.

Be sure to replace the gravel back onto the repair section before the roofing cement sets. This will help protect your roofing membrane from any additional sun and weather damage.

If you have completed these repairs and several months later continue to have the same problems or more severe problems, it can be helpful to call a professional commercial roof contractor to replace your roof or complete more advanced repairs for you.