How to Repair a Rubber EPDM Roof

Rubber EPDM (ethylene propylene diene monomer) roofs are a popular choice for flat and low-slope commercial and residential buildings. EPDM is lightweight, durable, and relatively inexpensive. However, like any roof, EPDM roofs are subject to wear and tear over time and may eventually need repairs. Knowing how to properly repair an EPDM roof can save thousands of dollars in replacement costs.

Assessing Damage on an EPDM Roof

The first step in repairing an EPDM roof is thoroughly inspecting it to identify any problem areas. Look for:

Cracking or blisters in the EPDM membrane
Loose, open, or improperly sealed seams
Punctures from falling or wind-blown debris
Evidence of ponded water due to poor drainage
Exposed underlying materials due to wind damage or loss of ballast
Damage around roof penetrations like vents, skylights, etc.
Deterioration and cracks in flashings
Mineral buildup due to ponding water

Carefully inspect places where water could enter through the roof, like drains, edges, seams, and penetrations. Probe any suspect areas with a screwdriver to check for soft, damaged spots. Mark any issues to be repaired.

Cleaning and Prepping an EPDM Roof Before Repairs

Once you’ve identified necessary repairs, the roof surface must be cleaned. Sweep away any loose debris. Use a general cleaner or diluted bleach solution to remove dirt, residue, and mineral deposits. Avoid oil-based products that could degrade the EPDM. Rinse thoroughly.

The roof should be dry before starting repairs. Allow 1-2 days of sunny weather beforehand. Heat from the sun can also make the EPDM more pliable and easier to work with.

Repair supplies like adhesives, tapes, patches, etc. should be set up in a central location to avoid repeatedly climbing on and off the roof. Have clean rags, a utility knife, scissors, and other tools on hand.

Repairing Seams and Patching Holes in an EPDM Roof

Loose or improperly sealed seams are a major source of leaks in EPDM roofs. Here’s how to repair them:

With a wire brush, buff 1-2 inches of the membrane on both sides of the seam. This improves adhesion.
Apply a primer to the buffed area and let dry completely.
Roll a 2-4 inch wide EPDM primer tape centered over the seam. Apply firm pressure to bond it.
Apply a 3-4 inch wide EPDM cover tape over the primer tape, also centered on the seam. Smooth any air pockets.

For small punctures less than 1″, carefully clean the area then apply a round EPDM patch using bonding adhesive, smoothing out any air bubbles.

For larger holes, cuts, or cracks:

Clean and buff the area surrounding the damage.
Cut an oval or round EPDM patch slightly larger than the hole.
Apply bonding adhesive to both surfaces and let tack up.
Firmly press the patch in place over the damage.

Repairing Flashings on an EPDM Roof

Flashings provide the waterproof barrier where the roof meets walls, vents, drains, and other penetrations. Cracks here can lead to leaks, so flashings must be maintained.

Thoroughly clean the flashing and surrounding EPDM membrane.
Apply primer then bonding adhesive to both surfaces.
Cut a piece of EPDM sheeting slightly larger than the damaged area.
Once adhesive has tacked, firmly press the patch into place.
Use a hand roller to smooth out any air pockets or wrinkles.

For long cracks, apply a covering EPDM flap in the same way after priming and applying adhesive on both sides of the crack. Seal the edges.

How to Repair EPDM Roof Ballast and Insulation

EPDM roofs are held down by ballast like gravel, pavers, or rubber mats. Wind or storms may shift this over time, exposing the roofing membrane. Repair any sections where underlying materials are visible by:

Sweeping loose ballast back into place if possible.
Setting any displaced insulation or recovery boards back in their proper positions.
Replacing ballast that has blown away completely. Use the same type and amount specified by the roofing manufacturer.
Check for tears, gaps, or damage in the EPDM caused by wind-blown debris. Patch any holes or separated seams you find.

Make sure roof insulation boards fit snugly together. Relocate or replace any sections that are waterlogged, compressed, or damaged.

Repairing Roof Penetrations

Proper sealing around vents, pipes, skylights, and other roof penetrations is crucial. Leaks often form here due to damage, deterioration, or improper installation. To repair:

Remove old flashings, sealants, and termination bars around the penetration. Clean the area.
Prime and apply bonding adhesive to the base of the penetration and the surrounding EPDM roofing.
Cut a piece of EPDM at least 12 inches larger than the penetration base.
Set the EPDM in place over the adhesive and fold up the sides.
Firmly press to bond and eliminate any air pockets.
Secure with a termination bar bolted into the penetration base.
Apply sealant around edges for a watertight seal.

Check that water flows away from roof penetrations. Add or improve crickets and saddles if needed.

How to Repair EPDM Roof Drains

Clogged, leaky, or improperly installed drains can lead to water ponding and roof damage. Here are tips for fixing them:

Clear any debris from the drain bowl and pipe using a auger, plunger, or water jet.
Check connections for cracks or detachment from the roof or downpipe. Reattach and seal any loose joints.
If the drain bowl is badly damaged, replace it. Set the new bowl in roof adhesive and bolt it in place.
Cut back surrounding EPDM membrane if deteriorated. Prime and adhere a new EPDM patch.
Make sure roof slopes encourage water flow to drains. Add or improve tapered insulation around the drain.
Install overflow drains near existing primary drains as a backup drainage system.

Tips for Long-Term EPDM Roof Repair and Care

Inspect the roof 2-4 times per year and after major storms. Spot repairs promptly to avoid bigger issues.
Have a professional inspect and tune up the roof every 3-5 years. This can extend the roof’s lifespan.
Keep the roof clear of debris that could clog drains or abrade the EPDM surface.
Avoid unnecessary foot traffic which can damage roofing components.
Keep nearby trees and vegetation trimmed back to prevent leaves and debris from accumulating.
Install screens in drains to keep them from clogging with runoff gunk.
Improve drainage and flatten ponding areas with tapered insulation boards.

With proper care and maintenance, an EPDM roof can last over 25 years! Knowing how to repair common issues will keep your roof going strong.

Frequently Asked Questions About Repairing EPDM Roofs

What are some common problems with EPDM roofs?

Some common EPDM roof problems include seam and flashing failures, punctures, poor drainage leading to ponding water, loss of ballast exposing the membrane, and leaks at penetrations. EPDM can also become brittle and crack over time.

What tools do I need to repair an EPDM roof?

Basic tools for DIY EPDM roof repairs include a utility knife, scissors, wire brush, hand roller, general household cleaner, rags, a broom or blower, and a cordless drill with bits. You’ll also need materials like EPDM primer, tape, patches, and bonding adhesive.

How do I know when an EPDM roof needs full replacement?

If the EPDM surface is very brittle or has extensive cracking and damage, or if repairs would be very difficult or extensive, full roof replacement may be needed. An experienced roofer can assess the condition and expected lifespan during an inspection.

Can I layer new EPDM over an existing EPDM roof?

Adding a new layer of EPDM roofing over an older EPDM membrane is not usually recommended, as this adds weight and can trap moisture. It’s better to completely remove and replace deteriorated EPDM roofing.

How much does EPDM roof repair cost compared to replacement?

The cost to repair an EPDM roof varies greatly depending on the repair needed. Small punctures may cost $100-500 to patch, while re-sealing many seams or replacing large sections could run $5-20 per square foot. Full roof replacement ranges from $4-8 per square foot installed.

Conclusion

Performing repairs as soon as issues arise is key to maximizing an EPDM roof lifespan. Look for common problems like seam failures, punctures, poor drainage, and flashing leaks. With the right materials and some DIY know-how, many EPDM roof repairs can be completed at a fraction of full replacement cost. Address problems promptly and make regular maintenance a priority for lasting value from your EPDM roof.