So you've gone and done it: You bought a rig with a rubber roof. No more annual seam sealing! No more worries about leaks! A life of ease and comfort! Right? Well,--almost right. EPDM rubber roofs on RVs are like butter on sliced bread. But even then, there's still a little bit of maintenance to be done--and a lot of hype on how to do it. We hope to give you the low-down on what's high-up.
Clean It Up
Considered by the industry to be a "most versatile and long lasting" material, EPDM (Ethylene Propylene Diene Monomer) has become quite fashionable for a roofing material on RVs. And they may have something. EPDM has been used in the building industry for nigh unto three decades, and has proved itself a worthy contender in the race to keep the rain out. And put over the top of a plywood deck, an EPDM roof has strength, and the ability to resist delamination, pitting, or seam splitting, which has been one of the banes of RV maintenance.
One thing that rubber roofs aren't however, is maintenance free. True, there's no need to coat seems, or the entire roof, in the annual fight against sunlight or leaks. But EPDM does want a little of your attention, and in doing so, you'll pay yourself dividends.
The simplest rule for a rubber roof owner: Keep it clean. Count on rubber roof cleaning as a quarterly affair: Four times a year bring out the bucket of soapy water, a hose, and a medium bristle brush.
"Soap," you ask--perhaps incredulously. Yep, simple soap and water are all that you'll really need for the typical quarterly cleaning. To avoid voiding your warranty, make sure it's not an abrasive soap--keep the Comet in the closet. Rinse down your roof with a garden hose, then scrub down with that medium brush and plenty of suds. Now a good thorough rinse down with the garden hose and you're done with the wash-down.
"Ah, but I've got tree sap on my roof! Soap and water'll never handle that!" Okay, maybe there are a couple of stains. Here's where caution--and mineral spirits--come in. Pour mineral spirits on a rag--NOT DIRECTLY ON THE ROOF--and carefully scrub the affected area. Scrub only enough to get the stains out. Don't use any other type of citrus cleaners or other petroleum distillate products.
Check It Out
After a good dry-down, CAREFULLY ascend and check all caulking, looking for surface cracks, or any areas where the caulk is pulling away from the roofing material. If you find any areas that need attention, you'll need the appropriate caulking material. What's appropriate? Self-leveling butyl rubber caulk, NEVER SILICONE sealants of any sort.
"What's wrong with silicone?" After "apparently" curing, silicone rubber sealants have an awful falling out with EPDM roofs. They simply peel away in strips, leaving the owner with a false sense of security, and a place for water to find its way in. Butyl rubber sealants, on the other hand, have the stick-to-itiveness required for the job.
Should you find your caulking is "cracking up" literally, then apply a thin layer of butyl rubber caulk over the cracked sealants. Here is where the "more is better" philosophy is dead. Use the least amount of sealant as you can, and remember that a 1/4" bead of sealant will level out to a 1/2" wide patch.
If the caulking is actually pulling away, resist the temptation to take a handy putty knife after it. Instead, lift the loose end of the sealant with your fingernail and pull away until you can't pull any more away. Now clean up the area with mineral spirits or rubbing alcohol (once again, applied only ON a rag). After thoroughly drying, reseal the area with butyl caulk.
Fixing Damage
While rubber roofs are fairly tough, a misplaced tree branch can put nasty little holes in the roof. Panic not, most EPDM rubber roof damage can be repaired by the owner. Dicor Corporation, a major EPDM roofing distributor to the RV industry, produces two repair kits. For smaller repair areas, a "peel and stick" kit makes repairs a snap. You simply cut repair material to overlap the damaged area, peel off the backing, stick it down, and then feather in lap cement using a tool included in the kit.
The Dicor kit for larger damage includes a piece of rubber membrane 3' x 3'. Here the process is a little more complicated, but not impossible. The material is cut to size, and roofing adhesive is applied and "flashed," somewhat like what you did when you repaired your old bicycle intertubes. No, George, keep your matches in your pocket, this stuff's really flammable, and you just have to let the air "flash it." After the adhesive is ready, you apply the membrane, and seal it down with lap cement. Both kits include complete instructions, and a phone number to call for advice.
What About After Market Products?
An RVer's curse, somewhat akin to "your mother wears combat boots," must be "your rig has black streaks!" Ah, those cussed black lines that run down the side of the roof. From where do they come, and how can you cope with them? To simplify guilt establishment, point the finger at the sky, and then at yourself. "Atmospheric dirt," which probably includes air pollution, is a chief cause of black streaks on white rubber roofs. Couple an accumulation of the atmospheric dirt with a failure to wash down your roof often enough, and that old black magic--er--black streak problem, occurs.
You may have heard of various aftermarket nostrums "guaranteed" to stop black streaks. For that matter, there are whole classes of roof potions to "protect against UV damage," etcetera, etcetera, that leap up at us from the shelves of RV suppliers. Don't buy a bill of goods.
First, EPDM is NOT susceptible to ultraviolet light damage.
Second, that white powdering is normal--call it oxidation. If you wash your roof every quarter, you'll see less of it.
Third, and perhaps most important, some aftermarket products can actually damage--and likely void the warranty of--EPDM roofs. ANY product that contains petroleum distillates (which may be cleverly hidden behind other verbose sounding words printed on the label) can damage EPDM. Swelling and loss of adhesion is not uncommon for EPDM roofs saturated by petroleum distillates.
Still, how do you know if the 'product of choice' has any of those EPDM bogeymen? Ask the maker for a Material Safety Data Sheet. Run your eye down to the section headed "hazardous ingredients." If there are any "petroleum distillates" listed here, then the use of that product should be out of bounds.
Okay troops: Bucket, ladder, brush and hose at the ready. Check out the calendar. If it's been three months or more since your last roof cleaning foray, set the feet to moving! You'll never have to listen again to the taunts of "Your RV has black streaks!"
