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How To Fix a Flat Roof Leak: How to Repair, Patch, Tips, and More!

how to fix a flat roof leak puddle

A leaking roof is no one’s idea of a good day. Whether it is a slowly growing water stain in the ceiling, or an active drip every few seconds, any leak can cause expensive water damage if ignored. That’s why it’s best to learn how to fix a flat roof leak so you can stop any damage fast!

But how do you fix a flat roof leak? There’s a lot to cover, but we’ve done the research for you, so when you find a leak, you can jump into action. Read on to learn all about how to fix a flat roof leak.

When Should I Repair a Flat Roof?

Obviously, if your roof is leaking, it is in need of some TLC. But there are other signs to watch out for that can indicate that it is time for a flat roof repair.

  • Mold and Moss Growth – If you are noticing mold, moss, or algae beginning to grow on your roof, it’s a sure sign that moisture is not properly evaporating.
  • Water Pooling – While some water pooling after a rainstorm is normal, water pooling on your roof for an extended amount of time could be a sign that the structure of your roof is failing.
  • Water Stains – If you see water stains on your ceilings and walls, it’s a good idea to call in a professional to assess whether or not the leak is coming from your roof
  • Blistering – Blistering or bubbling on your roof’s surface means that your roof may no longer be adhering properly.

how to fix a flat roof leak wet spot

Why is My Flat Roof Leaking?

There are all sorts of reasons your flat roof may be leaking. All roofs eventually face some wear and tear from continued exposure to the weather. Hot, sunny weather causes roofing material to expand or dry out, while colder weather can make it contract. This can lead to cracks and warping, making a flat roof repair necessary.

If your area has recently experienced natural disasters, such as a tornado, hurricane, or hailstorm, your roof is vulnerable to extensive damage. Be sure to check it as soon as possible.

The truth, though, is that sometimes roofs just fail because of age. Most flat roofs will last an average of 10-20 years. As your roof ages, it is more prone to damage that can cause leaks. If your roof is within that age range, it may simply be time for a roof replacement.

How to Find the Leaking Area

If your commercial building has a flat roof, you are in luck! Leaks and damage are much easier to spot on a flat roof vs. a sloped roof. The easiest solution is to look directly above the spot where the indoor leak is occurring. If you cannot see any visible signs of damage, be sure to check the areas of your roof that could cause water to run off into this area. Despite the name, most flat roofs have a slight slope in order to allow water to run off.

Types of Flat Roof Materials

The type of flat roof repair you need will be highly dependent on its roofing systems and material. Here are some of the most common types of flat roof materials on the market.

how to fix a flat roof leak patching roof

Modified Bitumen

Modified bitumen is made of asphalt and fiberglass and installed in a multi-ply system.

Built-Up Roofing

A built-up roof has several layers of roofing material that are melded together with hot tile and then topped with stone.

EPDM Roofing

EPDM roofing consists of durable rubber that can be attached in a variety of different ways. This is typically one of the easiest types of roofing materials to install.

TPO Roofing

TPO consists of a single-ply roof membrane that is made out of rubber.

PVC Roofing

PVC is a single-ply roofing system that is known for being lightweight and increasingly popular amongst roofing contractors.

How to Fix Flat Roof Leaks: DIY

If your roof has a small leaking area that needs patching, it is possible that you can do it yourself. However, larger flat roof repairs or a full flat roof replacement is best left to a professional.

So, what’s a determined DIY-er to do? You can create a temporary fix to stop roof damage in its tracks!

Once you find the damaged area of your roof, take some time to clear the area of debris. You’ll want a clean surface in order to create the best possible fix. Carefully cut around the blistered area of the roof, and dry any moisture you find beneath it.

After you have peeled back all of the layers of the roof membrane, you can apply roofing cement to the leaking area. This will stop water from being able to enter your building for the time being.

The wet roofing cement will adhere to the membrane when you replace it. Make sure to press on it to ensure that it sticks. You will then want to nail the membrane to the roof to ensure that no water can get through. This temporary roof repair should help you prevent further damage until a professional can assess the problem.

How to Fix Flat Roof Leaks: Professional

When it comes to flat roof repair options, a professional roofing company is your best bet to ensure the problem does not happen again. Most roofs come with a warranty, and you may be able to get the necessary repairs without much cost to you.

A professional roofer will perform a roof inspection and advise you as to the next steps. If you do not need a full roof repair, they may suggest that you consider a roof coating.

A roof coating will help seal your roof to prevent further damage.

team installing and repairing flat roof

How Much Will It Cost to Fix a Leaking Flat Roof?

The cost of repairing a flat roof will vary greatly, depending on the state of your roof. A full flat roof replacement will cost between $5000-$15,000, depending on the size.

If only a roof repair is needed, then you can expect to pay $300-$1000.

The Best Way to Fix a Flat Roof Leak

Roof leaks are an inevitable reality of life, especially if you have an older leak. While DIY repairs can help slow the leak, it’s best to call in the professionals to ensure a proper repair is made so you can rest easy knowing your roof is working effectively.

At Anchorpoint Roofing, we take the stress out of caring for your roof. Our team of highly skilled professionals is here for you to ensure that your residential and commercial roofs are cared for. Contact us today for a free quote!

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