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4 Essential Steps to Fix a Leaking Flat Roof

Ponding standing water on a flat roof after heavy rain

Fixing a flat roof leak

In 2024, flat roofs are mostly water-resistant, with homeowners usually not having to worry about water damage. But flat roofs have not always had the best reputation, as in the past, they’ve been known to be more challenging to get rainwater to run off them.

However, with the involvement of professionals and innovative rubber materials, it’s possible to extend the life of flat roofs and preventing leaks altogether.

But if your current flat roof has not been installed to be watertight, or you’re noticing water pooling, then it’s likely that the water will work its way through the materials – which is why it’s especially vital to waterproof your roof and maintain them. But first, let’s walk you through the steps to repair your leaking flat roof, and then advise you on the best next steps to keep it dry!

Follow These Steps to Fix Leaks & Keep Your Roof Dry

Tips from roofing experts

Fixing A Flat Roof

Step 1:

Identifying the Source of the Flat Roof Leak

  • Carefully inspect the flat roof, paying close attention to signs of damage like cracks, tears, or gaps in your roofing material. Pay special attention to areas where water might accumulate or build up, like around drains, vents or flashing. This will prevent future leaking.
  • A hose can simulate rainfall so you can observe where water runs off and where water enters the roof.
  • Determine the extent of the damage. Involve a professional if you have to.

Step 2:

Clean and Prepare the Flat Roof Surface

  • Clean and prepare the roof surface for repair materials. If your roof material is EPDM, you can use our EPDM Membrane Cleaner (£11.99) to remove contaminants from the surface.
  • Remove debris, dirt and loose roof material using a brush or pressure washer.
  • Before repairing, ensure the surface is dry and free of moisture. This will allow the sealants and new materials to adhere properly.
  • Primers can be ensured to improve adhesion and ensure a long-lasting repair. Explore our EPDM Primer (£7.50).
  • 5″ Circular Patch (£7.50) designed to flash outside corners or to be used as a cover patch for small repairs.
  • 12″ Uncured Flashing Tape (£24.00) – ideal for flashing and waterproofing.
  • Flashing can prevent leaks on a flat roof and is typically installed around roof penetrations like vents and chimneys. See flashing products.
  • Adhesives and sealants from £9.00. See all.
roof cleaning image

Step 3

Apply Rubber Roofing Sealant

Using a rubber roofing sealant is a versatile and durable solution for repairing leaks in flat roofs, as it forms a flexible, waterproof barrier that withstands harsh weather conditions and temperatures.

  • Using a brush, generously apply the rubber roofing sealant to areas where the leak occurs. See professional kits.
  • Overlap the damaged area of the roof by several inches to create a watertight seal.
  • Allow the sealant to dry completely according to instructions, and proceed to the next step.

Step 4

Perform Regular Maintenance

The trick to avoiding a leaking flat roof is prevention and maintenance. You can prolong the life of your flat roof by performing regular maintenance checks to inspect for any signs of wear or damage.

Ensure the roof is clear and clean of debris to prevent water from pooling. Also trim any overhanging branches or any vegetation that could cause damage to the roof’s surface. Protective coating or sealants can also further enhance the waterproofing quality of your rubber roof.

Invest in quality roofing materials.

maintaining flat roof