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How to Fix a Leaky Flat Roof

[fa icon="calendar"] Sep 7, 2021 9:30:00 AM / by Krystal Coddington

Krystal Coddington

what to do about a leaky flat roof

If you own a commercial building in the Las Vegas valley, the odds are that it has a flat roof. While these are popular among builders and business owners due to their low cost and ease of maintenance, if you fall behind with your flat roof repairs, the roof could quickly deteriorate in the event of a major storm. Sometimes you may not know you have an issue until it’s too late and your leaky flat roof turned the inside of your building into a swimming pool.


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How to Tell You Need Flat Roof Repair

Flat commercial roofs have a finite lifespan. Over the years, the hot Las Vegas sun can break down roofing material that protects your building’s roof from leaks. Below are some ways to tell you need flat roof repair:

  • Repeated, extensive water pooling on the roof
  • Large tears, cracks, or rips in the roof or seams
  • Blistering and bubbling from adhesion failure
  • The presence of moisture and leaks inside the building
  • The pulling away of flashing from the corners of the roof
  • The presence of lichen, mold, moss, and\or algae
  • Damaged top coat

Some commercial roofs are made of materials that hide problems. It is best to call professional roofing contractors to address these unseen problems.


What to Do When Your Flat Roof Leaks in Heavy Rain

Nothing is quite as concerning as seeing a constant drip of water coming from your ceiling. This is a possibility if you neglect to repair your roof. As water flows from your ceiling during heavy rain, there is little you can do. But to limit the water damage, here are some ways to repair flat roof leaks:

  • Locate the source or location of the leak by checking the ceiling and attic to find the leak.
  • Put containers under the leak to catch the water. To keep your floor as dry as possible and safe to walk on, collect the leaking water in buckets and mop around the area regularly.
  • Call a commercial flat roofing repair company like The Original Roofing Company. Professional roof technicians will have the knowledge and equipment needed to quickly and temporarily stop the leak.

What Causes Flat Roof Leaks?

There are many causes of flat roof leaks. The common sources include the following:

  • Inadequate drainage. If your roof can’t properly drain water, it will pool. Over time, standing water can destroy roofing materials that make the roof susceptible to leaks.
  • An old roof. Older roofs are more prone to leaks as years of heat, sun, rain, and wind destroy the roofing material.
  • Damaged flashing. Improperly installed or damaged flashing leaves the corners of the roof exposed to the elements, including rain. Poor flashing can allow water to penetrate the roofing system.
  • Problematic roof membrane. Tears, cracks, punctures, shrinking, and blistering of the roof membrane leave the interior of the roof vulnerable to water damage and leaks.
  • Standing water. Water is heavy and even a small puddle of standing water can cause excessive strain, wear, and tear on your flat roof. These factors ultimately weaken the roof to the point where it can no longer stand up against leaks.
Open roof penetrations. Holes must be made in the roof membrane to accommodate vents, pipes, drains, and HVAC units. Over time, the gaps in these holes are no longer watertight. Water can seep into the membrane and the roofing system and cause leaks.

Where is your building’s roof in its life cycle? Take the free quiz today!


How to Temporarily Fix a Leaking Flat Roof

You may want to save money until you have the budget to invest in the necessary repairs for your roof, which means you’ll need to make some repairs of your own.

Find 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.

Get on 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.

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.

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.

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.

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.

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.

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.


Related: 6 Ways to Extend the Life of Your Commercial Roof


Flat Roof Repair Costs

The current average cost of flat roof repair is $600, with an average range of $250-$1,000. The costs will vary depending on the cause of the damage, the size and condition of the roof, the type of roofing material, and the extent of repairs. The cheapest repairs are around $50 for a small area with minor damage. Extensive damage over a large area of the roof can cost upwards of $5,000. Most professional roofing repair companies charge $3-$10 per square foot. Fiberglass roofs are the cheapest to repair while metal roofs are the most expensive.

It is important to know that if you have an emergency roof leak, expect to pay more for repairs. Many companies charge an extra $100-$200 for emergency repairs. Additionally, some flat roof repair companies have a minimum charge for emergencies.


Flat Roof Repair Option: Roof Coatings

Here in Las Vegas, roofs are constantly exposed to high temperatures that cause a gradual breakdown of the roofing materials. The weakening of the roof may not be noticeable until a rainstorm hits. If you’ve noticed a minor leak or other wear and tear on your industrial or commercial roof, you could simply patch the problem area for a temporary fix. However, you’ll need to repeatedly replace the patches. The leak may also worsen over time, leading to worsening damage and high flat roof repair costs. Alternatively, you could add a roof coating to protect against future leaks. The professional technicians from The Original Roofing Company can show you your flat roof repair options so you can protect your investment for as long as possible.

Instead of simply patching a leak, you may want to go a step further to fully protect your roof by getting a roof coating. This consists of a thin layer of synthetic material that can give your roof long-term protection from the elements. A roof coating can be painted on in as little as a day (or over the course of several depending on the size of your building) and does not require tenants to vacate during work. This flat roof repair option provides much more comprehensive coverage than a few repairs and costs far less than a full roof replacement.

In addition to stopping leaks, a roof coating can also drive down power costs by up to 50% since it will reflect more sunlight off of your building. A roof coating can extend the roof's life by anywhere from 5 to 7 years, which gives your business time to plan for a replacement. You can also claim a federal tax credit after obtaining a roof coating, which isn’t something available with full flat roof replacements.

While you can’t avoid every leak, with regular maintenance you can spot damaged areas on your roof before they become major problems. You should get a roof inspection to assess what the damage is to your commercial building to avoid a full roof replacement. Your building is a major investment and a working piece of capital, and your roof absorbs damage daily while protecting it. By conducting regular maintenance and inspections, you can be sure it will keep producing value for you for years to come. Whether it’s flat roof maintenance or repair, the professional technicians from The Original Roofing Company can show you your flat roof repair options so you can protect your investment for as long as possible.


Related: Reflective Roof Coatings: What Are the Benefits?


Get Flat Roof Repair From The Best Roofers in Las Vegas

Though it doesn’t rain frequently in Las Vegas, 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.

The Original 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 Original 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.


download the preventative roof maintenance checklist


Krystal Coddington

Written by Krystal Coddington