David Contreras, owner of DC Roofing of Arizona, has been roofing in Tucson since 2011, and he personally walks the Green Valley roofs we estimate. EPDM is a black or white synthetic rubber roofing sheet used on flat and low-slope roofs. It's tough, it stays flexible in the heat, and when it leaks the cause is usually small and specific: a seam, a flashing detail, or a patch made with the wrong product. This page covers how to recognize an EPDM roof, why the most common patch makes things worse, where leaks start, and how we decide between repair, coating, and replacement. We're licensed, bonded, and insured (ROC #328733), with $1M per occurrence and $2M aggregate in general liability coverage.
Is Your Flat Roof Actually EPDM?
A lot of people call any flat roof a "rubber roof." Knowing what you really have matters, because each type is repaired differently. According to the EPDM Roofing Association, EPDM comes in black, gray, and white, in thicknesses of 45, 60, and 90 mils, and its seams are sealed with liquid adhesive or special tape. Here's how it compares to the other flat roofs we see:
- EPDM: large sheets that feel like a heavy inner tube, usually black, with overlapping seams glued or taped together
- TPO: usually white, smoother and stiffer, with seams welded together with heat
- Foam: a sprayed, slightly bumpy surface under a coating, with no seams at all
- Built-up or gravel roofs: layers of felt and asphalt, often with gravel on top
If you can't tell from a ladder, that's fine. Please don't walk on a flat roof to find out. We'll identify it during the inspection.
The Patch That Makes EPDM Leaks Worse
The most common EPDM "repair" we run into is black roof cement or tar smeared over a leak. It looks like a fix. It isn't. EPDM manufacturers warn against using petroleum-based products like asphalt roof cement on their membranes, because asphalt products aren't compatible with EPDM rubber and can degrade it. The patch may slow the leak for a while, then fail, and now the area around it has to be cleaned up or cut out before a real repair will stick.
A proper EPDM repair stays inside the EPDM product family: the area is cleaned, primed with an EPDM primer, and covered with EPDM tape or a membrane patch that extends well past the damage, with the edges sealed. It's not complicated, but every step matters, and skipping the primer or working on a dirty surface is how patches lift.
Where EPDM Roofs Leak
EPDM itself rarely wears through in the middle of the sheet. Leaks start at the edges and the details:
- Seams. Older EPDM roofs used contact cement at the laps. Years of daily heating and cooling can loosen it until an edge lifts.
- Wall and parapet flashing. Where the membrane turns up a wall, water gets behind loose flashing and runs down inside.
- Pipes, vents, and cooler curbs. Every hole through the roof is a place to seal, and evaporative cooler curbs are one of the most common leak sources on flat roofs around here.
- Punctures. Branches blown onto the roof during a monsoon storm, or a dropped tool from another trade, can poke through.
Because the ceiling stain is often a few feet from the actual hole, David traces the leak on the roof, not just from inside the house.
Repair, Coat, or Replace
If the leak is one seam or one flashing detail on a roof that's otherwise sound, repair it. Our repairs carry a 2-year labor warranty, and we'll tell you straight when a repair is all you need.
If the membrane is still well attached but tired, a reflective coating can extend its life. EPDM needs its own cleaning and primer step before a coating will stick, and we test adhesion before committing to the whole roof.
If the rubber has gone brittle, seams are failing in several places, or the insulation underneath is wet, it's time to replace it. At that point we'll price both a new EPDM roof and a white TPO roof so you can compare. Flat re-roofs typically take two to four days and carry our 5-year labor warranty. Our EPDM roofing page goes into installation details.
A Note for Green Valley Homeowners
Whoever you hire, ask for their license number first. A licensed contractor's ROC number is the one detail any property owner should have in hand before work starts. Ours is #328733.
Green Valley is unincorporated, so permits go through Pima County. A seam repair doesn't need one. If a replacement turns up rotted decking that has to be rebuilt, that's structural roof work, which the County lists as needing a permit. And if climbing a ladder to check a flat roof isn't something you should be doing, don't. A free inspection is what we're here for, and every project we complete comes with free annual inspections after.
FAQ: EPDM Roofing in Green Valley
Can I patch my rubber roof with roof cement from the hardware store?
Please don't. EPDM manufacturers warn against petroleum-based products like asphalt roof cement on their membranes because they aren't compatible with the rubber and can degrade it. The patch tends to fail, and then it has to be cleaned off or cut out before a proper EPDM repair will bond.
How do I know where my EPDM roof is actually leaking?
Usually you can't tell from inside. Water travels under the membrane and along the deck before it shows up as a ceiling stain, so the hole can be several feet away. David traces it on the roof, starting with seams, wall flashing, pipes, and cooler curbs, which is where most EPDM leaks start.
Is it worth repairing an older EPDM roof?
Often, yes. If the rubber is still flexible and the leak is in one seam or one flashing detail, a repair is the right call. If the membrane is brittle, seams are failing in several places, or the insulation underneath is wet, repairs turn into a cycle and replacement makes more sense. We'll tell you which one you're looking at.
Can you put a white coating over black EPDM?
Yes, if the membrane is sound and well attached. EPDM needs a specific cleaning and primer step before a coating will bond, and we test adhesion on a small area first. A coating won't fix a membrane that's already failing, so any repairs come first.
If I replace my EPDM roof, should I go back to EPDM?
Not automatically. White TPO reflects far more sun than black EPDM, which matters in this climate, while EPDM can make sense on some budgets and roof layouts. We price both so you can compare them side by side.
Do I need a permit for EPDM roof work in Green Valley?
Green Valley is in unincorporated Pima County, so permits go through the County. A repair doesn't need one. Pima County lists structural roof work as needing a permit, so if a replacement involves rebuilding rotted decking, that part may. We check the current rules before work starts.
What warranty comes with EPDM work?
Repairs carry a 2-year labor warranty, and flat roof replacements carry a 5-year labor warranty, plus the manufacturer's warranty on the materials. Every project we complete also includes free annual inspections.
