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We are experts at flat roofs specializing in flat roofs and flat roof repairs. Using the proper products can make the difference between a successful repair and one that does not accomplish its goals.

Are you looking for a way to repair a flat roof? One can have many different types of flat roofs, so knowing how to repair and maintain them is vital. A repaired flat roof can help ensure your property stays safe and secure by keeping out the elements. To help you understand the repair process, this guide will discuss the steps required to assess the issue, what materials to use for the repair, and essential information regarding safety and longevity.

Assessing the Damage

The first step to repairing a flat roof is to assess the damage that needs to be addressed. Different types of repair will be required based on the severity of the injury. A common issue is a tear in a membrane roof, which can happen when a roof is exposed to stress, particularly in harsher weather climates such as wind and hail storms. Other issues to look for include cracks, holes, and standing water on the roof. Once the source of the leak is identified, the repair process can begin.

Preparation for Repair

Once the source of the damage is identified, preparation is an essential step in the repair process. To ensure that the repair is completed correctly:

  1. Clear the roof of debris and remove any furniture or other materials in the way.
  2. Ensure all nails, screws, or any other exposed fasteners are removed.
  3. Clear the gutters and drains around the flat roof to reduce the risk of further damage caused by water buildup.

Types of Flat Roof Materials

Before finding the right repair materials, it is essential to identify what type of material your flat roof comprises. The most common materials used in flat roofs are EPDM rubber or modified bitumen membranes, which require different types of repair. Modified bitumen membranes are typically installed over an existing roof. In contrast, an EPDM rubber membrane is a single sheet of waterproof material, generally established as a self-adhesive or mechanically fastened sheet.

Choosing the Right Fasteners for Repair

When repairing a flat roof, it is vital to use the correct fastener for the job. Using the wrong buckle can result in an unstable repair that may fail. One should use either a mechanical fastener or a sealant with modified bitumen. Regarding the adhesive, a minimum 90-degree overlap should be used to ensure that the repair is secured, and it is essential to use spray-applied glue to provide the entire area is waterproofed.

Installing the Membrane for Repair

If the flat roof has been covered using either rubber or modified bitumen, the repair may include the installation of a new membrane. For an EPDM rubber membrane, use unique contact adhesive or string rubber cement to adhere to the new sheet. Care should be taken to ensure the sheet is laid over the entire repair area with no wrinkles or air bubbles trapped within the membrane. Finally, ensure the edges are secured for at least 3 inches up and 3 inches back from the damage.

The repair for a modified bitumen membrane is slightly more complex as the sheet is typically installed over an existing roof. If needed, a professional may be necessary to complete the repair correctly. Begin by arming the edges of the damage with further insulation material, such as foam or polystyrene sheets. The new membrane must be completely flat with no ridges, and correct fastening materials can follow.

Sealing and Caulking the Repairs

Once the repairs are completed, any exposed seams should be properly sealed using a specialized rubberized fabric. This process involves bonding the membrane with hot air and a torch. The sealant should also be applied to the roof surface as it helps to protect the decking from the weather and other elements that the roof will be exposed to. This also helps to form a tight seal to keep moisture out and prevent any issues from developing.

FAQs About Repair A Flat Roof

Q. What kind of flat roof membrane is most commonly used?

A. EPDM rubber and modified bitumen are The two most commonly used flat roof membranes.

Q. How often should I repair a flat roof?

A. It is suggested that annual inspections and repairs should be completed on a flat roof, and extra reviews in harsher weather climates are reported in the area.

Q. What kind of fasteners should I use to repair a flat roof?

A. Mechanical fasteners should be used to secure modified bitumen membranes, and an adhesive should be used to secure EPDM rubber membranes.

Q. Do I need to seal the overlap between the new and existing membranes?

A. Yes, it is essential to use a specialized rubberized fabric to bond both the new and existing membranes with hot air and a torch to create a tight seal.


Repair a flat roof can be a daunting job, but with the proper preparation and materials, it can be done relatively quickly. Identifying the type of flat roof membrane you’re working with and using the correct fasteners are important steps during the repair process. Additionally, sealing off the affected area afterward can help extend the life of your roof and keep you safe from the elements.