Comparing pitched roofs to flat roofs is like comparing apples and oranges. There are significant differences that in the types of roofing materials used. While shingles work well for steeper pitched roofs, flatter areas often single ply roofs. But flat roof leaks are a common occurrence in the roofing industry.

Flat Roof LeaksSince water does not stand on pitched roofs, leaks are often less frequent. But flat roof leaks often happen because water stands on them, especially without proper drainage. Sturdy single ply roofs are what is needed for these leak prone areas.

Flat roof leaks can become a big problem if the issue is not addressed immediately. Repairing or replacing single ply roofs can be done in a number of different ways. Each situation may require certain materials or methods to do the job properly the first time. The method and materials that you choose will depend on many factors, and these can include:

  • Cost
  • The location of the leak
  • The extent of the problem causing the leak
  • Roof size
  • Water damage already present
  • Structural damage
  • Warranty offered
  • Preferred materials

Before you can decide which way to go in order to stop and prevent leaks with your flat roof you need to understand what your options are. This will help you evaluate each possibility and find the right one for your specific roof, your individual budget, and your unique circumstances. The right answer for one situation may be the wrong solution for another situation.

Identify what is Causing Your Flat Roof Leaks

The very first step, as soon as you realize that you have flat roof leaks is to identify where the water is getting in, and this is not always easy. You may need to call in a roofing contractor with experience in your type of roof to pinpoint the cause of your leaks. Until these issues are identified, they cannot be repaired or resolved.

Water pools at the edges of the roof before flowing down the drains, and even a tiny gap in the flashing can allow leaks.


Should You Repair Single Ply Roofs or Replace Them Instead?

Single ply roofs that have flat roof leaks may require you to replace the roof rather than repair it in some cases. A professional roofer will be able to assess your specific roof and situation and recommend the best way to address your leaks and fix them. A very minor leak from a small hole may be a DIY project if you are handy, but hiring a professional is usually the best choice.

What Are Your Material Options with a Flat Roof?

If you have flat roof leaks and a replacement is called for then you have a number of options when it comes to the materials that will be used. There are several choices of material with flat roofs. We have listed three of the more popular systems for flat roof leaks.

Built-Up Roof (BUR) – Built-up roofs have been around for more than a century. They are often referred to as tar and gravel. Several layers of roofing material are laid down and sealed with hot asphalt or tar.

The asphalt or coal tar is heated in a kettle or tanker and then applied by mop or mechanical spreader.

Source: National Roofing Contractors Association

Rubber or EPDM – EPDM stands for ethylene propylene diene monomer. It is usually available in white or black. It is a single ply roofing membrane. It requires little maintenance when applied correctly.

Firestone RubberGard EPDM remains highly flexible even at temperatures down to -45°C, enabling year round installation. The membrane can also elongate over 300% to accommodate building movements and temperature fluctuations.


Modified Bitumen – This is another proven solution for flat roof leaks. It is made from a combination of a variety of solvents, modifiers, and asphalt.

A roof system composed of a built up roof membrane with 2 plies or 3 plies and a polymer-modified bitumen membrane cap sheet is commonly referred to as “hybrid” system.


Modified Bitumen

What are Green Roofs?

If you are experiencing flat roof leaks and you are considering a complete replacement, one possible choice is a green roof. Although these are not considered single ply roofs because of all the additional layers involved. Green roofs allow you to grow plants on the top of the roof but special moisture and vapor barrier layers are required and these roofs can be very expensive.

Which Flat Roof Repair Method for Leaks is best for You?

Once you notice flat roof leaks, it is important to find out what is going on. If there is simply a small breach in rubber roofing then repairs may be inexpensive and the right choice. If your roof is older and in poor shape then a full replacement at a higher cost may be necessary. Each case is unique, with different factors and different materials involved.

How have you fixed flat roof leaks in the past? Would you make the same choices today?

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