How Do I Fix Concrete Roof Leakage?

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16 November 2021 - 11:33, by , in Roofing, No comments

Concrete roof leakage is common as the concrete surface is more susceptible to scaling, cracking, crazing , spalling or many issues due to various wear and tear it is exposed to.

A concrete roof leak eventually occurs when the concrete is porous and permeable. This may be due to poor quality concrete or construction, or to any other severe structural damage. 

This article takes you through the procedure you must follow to fix a concrete roof leakage.

How to Fix Concrete Roof Leakage?

Step 1: Roof Inspection

There are many reasons why concrete roofs leak. To prevent further problems, it’s essential to identify the root cause of leaks and fix them. A roof inspection includes:

  1. Looking for ponding water
  2. Inspection of plumbing lines
  3. Check sides of the building roofs, corners, drainage pipes, etc
  4. Cracks in the concrete surface

In some cases, leaks are not visible to the naked eye. Permeable concrete can lead to a leak at another point if there is a drainage issue or water collects at one point.

Step 2: Call a Professional

Concrete roofs being one of the important parts of any building structure, it is always advised to contact a professional who has expertise in checking the leaks and its main cause. You can surely do your homework on finding the roof leakage issues. But when it comes to going into detail or in a more complicated situation, we cannot figure out the issue, then professional advice is the best choice.

Step 3: Repairing the Leaks

Once all internal causes of leaks like issues with plumbing lines or drainage issues exist, then it needs the first fix. After which the porous or cracked concrete roof must be fixed.

Before performing any method, the entire roof surface must be cleaned using a pressure washer. 

There are several methods that can be employed to repair cracks in concrete roofs, which are enlisted one by one. 


  1. Sealing the cracks using mortar or roof cement.  The cracks in concrete roofs can be filled using mortar or roof cement followed by a roof primer. Once dried, an elastomeric sealant can be applied over the cracks, holes, corners and other damaged areas. A second coat is advised to reinforce the sealant.
  2. Sealing the Concrete Roof Cracks Using Epoxy Resin or Acrylic resin
  3. Sealing the Concrete Roof Cracks Using Silicate-Based Sealant
  4. Sealing the Concrete Roof Cracks with expansion and construction joints using non-sag polyurethane sealants.
  5. Sealing using plasters or screed of 1:1 to 1:4 ratio mixed with waterproofing admixtures

Step 4: Waterproofing 

There are several methods to waterproof the roof surface. All concrete roof repair must be concluded with waterproofing on the entire roof surface, regardless of where the leaks are found.

Concrete roof waterproofing methods include:

  1. Application of elastomeric sealant
  2. Application of Bituminous or coal tar layer
  3. Installing waterproofing tiles and marble slabs using water seal joints
  4. Applying waterproofing layers or membranes

The figure below shows the typical cross-section of a concrete roof with proper waterproofing and sealants.

Step 5: Maintenance

Lastly, we not only need to stop concrete leakage but also prevent it from happening again. Regular roof maintenance is the only way to accomplish this. We recommend it at least twice a year. Commercial roofing providers should monitor and study concrete roof structures to find solutions to leaky concrete roofs.

Concrete roofs being a massive and important structure of a building, it is not advised to conduct any repair activity on it as a DIY project. But you can surely perform under the consent and supervision of a roofing specialist. Be safe while doing so, as professionals have license, skills, and equipment to operate, work and perform the task in a much easier, and excellent way.

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