Rubber roofs, sometimes technically referred to as EPDM roofs, are a common choice for low-sloped commercial and residential roofing systems. EPDM roofs have a long service life (up to 20 years), are safe to install, and are easy to maintain should leaks occur and require repairs.
1. Know which products to avoid.
To effectively repair a damaged area of an EPDM roof, you must select the right repair materials and handle the preparation and execution properly.
If the repair is sloppy, it may compromise the roof system leading to a reduced life expectancy and premature failure of the roof system.
Because EPDM roofs are composed of a synthetic rubber membrane, they are not compatible with asphalt-based repair products, like roof cement or asphalt-based coating materials. Do not use these materials to repair a rubber roof.
Using asphalt products can have terrible effects on EPDM roofing systems. If you or a contractor mistakenly use these products, the section should be cut out and replaced. If the repair is large enough, the entire system may need to be totally replaced.
2. Properly prep the roof surface.
The first step to repairing a rubber roof is properly preparing the roof’s surface.
EPDM roof systems have carbon within the membrane, and as the roof ages, the sheet develops a carbon film. This film, along with dirt and other debris, needs to be cleaned from the surface of the repair area to ensure the patch sticks to the membrane.
Clean the repair section
Pick a cleaner and wash the patch area, cleaning well beyond the area where the patch will be applied. Scrub away the oxidation from the surface, then wipe the surface down to remove all traces of moisture.
All dirt, oxidation, and carbon residue must be removed to allow the patch to stick properly to the membrane. Cleaning the surface properly will improve the patch’s lifespan.
3. Measure and cut the patch.
As the old adage says, measure twice, cut once.
1. Measure the roof patch before applying any primer.
2. Outline enough material to extend at least 2 inches beyond the damaged area in all directions.
3. Cut the patch to size, and clip or round off any corners to avoid any sharp edges that might be caught and lifted by high winds, debris, or foot traffic.
4. Prime the repair area.
Apply a thin primer coat to the area where the patch is going to be applied, either with a paint roller or paintbrush.
Use a liberal amount of the priming agent, getting well past the edges of where the patch will be applied.
5. Install the repair patch.
There are 2 common repair options for rubber roofs:
- Non-pressure membranes — require separate adhesive
- Pressure-sensitive membranes — have adhesive pre-applied to the underside of the membrane
Non-pressure roof repair patch
Use an EPDM adhesive to adhere the patch to the roofing membrane. Only use an adhesive designed for EPDM roofs.
Apply the adhesive to the underside of the patch and to the outline of the repair area. Allow the adhesive to dry slightly, and carefully place the patch over the repair area. Once the patch is positioned properly, use a steel roller to firmly set the material. Apply EPDM lap sealant around the edge of the patch to protect against water penetration.
Pressure-sensitive roof repair patch
Remove the film backing and firmly apply the patch to the repair area. Use a steel roller to evenly flatten the patch material and press out any trapped air. Apply EPDM lap sealant around the edge of the patch for additional protection against water penetration.
6. Hire a qualified commercial roofer.
Flat roof leaks require challenging repairs. If not performed correctly, minor problems could lead to major financial headaches.