An RV rubber (EPDM) roof doesn't need special tools to keep clean, but it does need the right cleaner. The wrong one can make the membrane swell and pull away from the deck. This guide follows Dicor's FAQ, product directions and roof care handbook: how often to clean, how to do it, what to use on tough stains, and what never to put on a rubber roof.
How often
Dicor's advice ranges from "at least twice a year" in its roof care handbook to "at least 4 times a year" with a medium-bristle brush in its FAQ, which is specific to EPDM roofs. The handbook's section on black streaks also recommends three to four times a year. If you park under trees, by the sea or on dusty roads, lean toward the higher number: Dicor's handbook points out that a shady spot under trees is where bird droppings, mulberries, pine sap and debris collect.
What never to use on a rubber roof
Dicor's FAQ and handbook are consistent on this:
- No cleaners or conditioners containing petroleum distillates. EPDM is made with petroleum products and reacts by swelling and sometimes discoloring. If it swells enough, it loosens from the substrate.
- No harsh abrasives.
- No citrus-based cleaners.
- Nothing that smells "fruity" or "flowery". Dicor says those scents attract birds, bees, squirrels, raccoons and other critters.
Dicor also warns that fruit, tree sap or harsh environmental fallout left on the roof for a long time can cause stains that won't come out. That is another reason to clean regularly.
What you need
- Dicor Rubber Roof Cleaner, which Dicor formulated for EPDM, TPO, vinyl and fiberglass. It comes as a 16 oz concentrate, a 32 oz trigger spray and a 1 gallon refill. Dicor says its water-softening agents fight hard-water spotting.
- A medium-bristle brush. Dicor's handbook recommends medium bristles for roofs. Dicor's wash brush with squeegee and 5-sided wash brush head are soft-bristle heads for general exterior washing.
- The Dicor telescopic extension pole, which reaches up to 9 ft and takes a garden hose, so you can work from a ladder.
- A hose or a pressure washer with a wide-pattern nozzle, not a concentrated stream.
- Plastic sheeting and masking tape for the sidewalls.
- Dicor Roof-Gard protectant for the finish (optional).
Step by step
- Mask the sides. Dicor's handbook recommends masking the sidewalls and caps from the roof edge down, because the rinse water carries cleaner and dirt down the sides and can leave streaks or damage graphics. If you don't mask, rinse the sides thoroughly afterward.
- Sweep or blow off loose debris.
- Work in small sections. Dicor suggests a 3 ft x 3 ft area at a time. Rinse it with a hose or wide-pattern pressure washer and let it drain.
- Spray on the cleaner and scrub in a circular motion with a sponge, medium-bristle brush, wash mitt or cloth.
- Rinse and move to the next section. On the roof, Dicor's pattern is to start in one corner, work across, step back, work across again, and so on toward the other end, so you are always moving away from the clean, wet area. Working in small areas also means you can do the whole job from a ladder or scaffold.
- Let it dry completely. Repeat on any area that still looks dirty.
Tough stains
| Stain | What Dicor suggests |
|---|---|
| Mold and mildew | Dicor's Mold & Mildew Remover contains bleach and is labeled for RV roof membranes. Spot test first, spray, wait a few minutes, wipe and rinse thoroughly, and keep it off the sidewalls. Dicor's FAQ notes nothing in the membrane itself promotes mold; it grows on dirt and organic matter. |
| Mold or mulberry stains that remain | The handbook says bleach or a bleach-based cleaner can remove them, and that a diluted 3% hydrogen peroxide solution is another option, but overuse of either can damage the rubber and the runoff can damage graphics. Use only as much as the stain needs. |
| Tree sap | First try ice: chilled sap often loosens enough to peel off. If that fails, the handbook allows mineral spirits with a big caution: never pour it on the roof. Put a small amount on a soft cloth, scrub only the stain, and wipe it up with another cloth. |
| Black streaks on the sides | Dicor's handbook says rubber roofs do not cause black streaks; they come from airborne pollutants washing off the roof. Cleaning more often is the best prevention. Dicor's Black Streak Remover is labeled for fiberglass, vinyl, aluminum and painted metal: spot test, spray, wait 30 to 60 seconds, wipe, rinse and towel dry. |
Protect it afterward
Dicor's FAQ says a Brite-Ply EPDM roof is supposed to oxidize: over a dozen years it may lose about 10% of its thickness to oxidation, which is normal. The chalky powder is the result. A UV protectant slows it and makes it harder for dirt to stick. Dicor's directions for Roof-Gard:
- Clean the roof first with Dicor Roof Cleaner and let it dry.
- Work out of direct sunlight, in 3 ft x 3 ft sections.
- Spray it on and spread it evenly with a soft cloth or sponge mop. Then let it air dry.
- One quart treats an RV up to 40 ft.
- For maximum UV protection, reapply every 3 to 5 weeks or after every cleaning.
Dicor's catalog says Roof-Gard contains no silicone, waxes, glycerine or petroleum distillates, and describes it as for all RV roofs, including rubber, vinyl, PVC, TPO and fiberglass. Our Dicor roof care kit pairs the cleaner with Roof-Gard.
Check the seals while you're up there
A clean roof is the best time to look at the sealant around vents, skylights and edges. Cracked, brittle, loose or curled sealant is where leaks start. See how to reseal an RV roof by roof type and patch, tape or sealant for small tears.
Safety
Dicor warns that a wet membrane can be extremely slippery. Its handbook recommends doing the work from ladders or scaffolding where you can, and having a service center clean the roof if you're not comfortable up there.
FAQ
Can I use Dicor Rubber Roof Cleaner on a TPO or fiberglass roof?
Yes. Dicor lists it for EPDM, TPO, vinyl and fiberglass.
Do I need Roof-Gard?
It's optional. Dicor says it helps fill the pores of the membrane, keeps the roof cleaner and adds UV protection.
Can I pressure wash a rubber roof?
Dicor's handbook suggests a hose or pressure washer with a wide-pattern nozzle for rinsing. Its Cleaner/Activator directions go further, calling for at least 2,000 psi with a 15 in spray pattern and the tip within 12 in of the roof. Either way, use a wide pattern, never a concentrated stream.
Where can I find everything?
All of it is in our Dicor collection. Found it cheaper? We'll beat it.