DIY Rubber Roof (EPDM) Repair — Learning To Fix Your Flat Roof

DIY Rubber Roof (EPDM) Repair - Learning To Fix Your Flat Roof

In this guide, we cover the newer method of rubber roof repair, using Peel & Stick + EPDM Primer method, which offers much better results than the older method of using splice adhesive. However, there might be a complicated repair situation on your roof that goes beyond the scope of this DIY guide.

With all our experience with flat and rubber roofing, even we sometimes run into these complex and unforeseen scenarios, which take considerably more time and flashing materials than we had initially anticipated, and basically test our skills in flat roof repair. We find that such cases are beyond the skill and knowledge level of most roofers and even advanced DIY homeowners. If you feel that your roof has one of these complicated cases, we recommend that you hire a professional to fix your rubber roof.

Before You Begin Your Rubber Roof Repair

First the following conditions should be met:

1. Ambient (outside) temperature MUST be 40 degrees F or higher otherwise the primer will either freeze or the bond will not be as strong as it is intended to be, thus your patch will leak prematurely.

2. Repair surface MUST be dry when you apply primer and patch otherwise the patch will not hold.

3. Before applying the patch, you must thoroughly clean the repair surface, remove any and all debris, dirt, any tar or other sealants / caulking that might have been applied.

4. It is recommended (but not necessary) in certain situations to also remove old lap caulk, before applying the new patch.

Here is what a rubber roof repair looks like on a real roof not in perfect factory conditions

Repairing Your Roof: Step-by-Step

RUBBER ROOF REPAIR VIDEO: How to apply rubber roof patch to an outside corner on a REAL roof (10 minutes long):

Step 1 Locate the Leak

Generally, a field sheet of rubber roof will not leak, unless there is a hole in it, and you can typically see these holes, when you remove all dirt and debris off the roof. Therefore, look for leaks in other not so visible spots.

Most leaks occur in common spots low spots on the roof, where water pools after rain. If you have a seam running through one of these low spots, there is 95% chance that there is a leak. Use a probe or even a nail, to test the seam for any voids / openings. Other spots include inside / outside corners, such as chimney / skylight curbs, or roof to wall connection or pipe flashing, etc.

Step 2 Prepare Roof Surface:

Once you locate the source of a leak, remove all dirt and debris, and using EPDM cleaner (do not use gasoline), clean the surface area thoroughly. Use a dish brush, if the dirt does not come off easily, and pour a little more cleaner over the surface area to clean it better. Once you clean the surface, use another clean rag and a little EPDM cleaner for the final thorough wipe of the repair area. Let the cleaner dry.

Step 3 Apply EPDM Primer

using a simple paint brush, apply a good (but not too thick) coat of EPDM primer, making sure it extends at least 2 beyond the edges of the patch that you are going to apply. Spread the primer evenly, so that you dont have too much in one place and not enough in the other. Make sure you dont have thick puddles of primer, as it will not completely dry, and your patch will not properly adhere.

Once you apply the primer, let it dry for about two-three minutes, depending on the weather, temperature, and how thick of a coat youve applied. Once you think the primer has dried do a tack and pull test.

Touch the center of primer with a clean, dry finger, and pull your finger off. If the primer does not stick to your finger, its ready for the patch to be applied. If you pull some primer with your finger, let it dry for another minute, and repeat the test.

Note: Primer must be dry before you apply the patch otherwise it will fail to adhere properly!

Also, if you applied primer over old glue (which is visible on a rubber roof) or some other sort of adhesive or sealant, which means you did not completely cleaned off the roof surface, the primer will dissolve this old sealant and it will take much longer to dry, before you can apply the patch. Do not add more primer over this spot. However, you might need to re-apply the primer to the area around such a spot, as the primer should not dry for too long.

Ideally, you should completely remove any such spots of old glue / sealant, and the rubber surface should be completely free of any foreign materials for best patch adhesion. You may use a plastic or metal scraper to scrape this old material off the rubber. Use additional cleaner and a brush for better results. Also, be careful if you are using a metal scraper,as not to tear / puncture the rubber membrane.

Step 4.1 Apply the Patch To a Flat Area

If you are applying a patch to a flat area (i.e. no inside or outside corners or other imperfections), this process should be very easy. Make your patch so that it sticks about 2-3 beyond the hole in the roof, and round off the corners with scissors. Once you confirm that the primer is dry, remove the film / paper off the back of your patch and slowly apply the patch to the roof surface, making sure you do not trap any air, so that you dont create any bubbles / air pockets between the patch and rubber membrane. Work your way out from one edge of the patch to the other. Once the patch has been placed down, roll it in with the silicone roller, with moderate pressure. Make sure you roll in the edges of the patch especially well.

Step 4.2 Apply the Patch To an Outside Corner:

Outside corner flashing video #2 filmed in studio by Rubber Roof Manufacturer

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