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Where the Rubber Meets the Roof

EPDM and TPO offer manufacturers a number of options when it comes to RV roofing.

A lot of people enjoy the RV life because it lets them get away from it all, while taking a little slice of home and the familiar with them.

Of course, that little bit of home also comes with many of the same concerns and issues a fixed address entails – plumbing, air-conditioning, even the roof. In fact, unless that RV is a six-figure motorhome, there’s a possibility the roofing material is the same for both abodes.

The good news for owners is that whether their roof is made of EPDM or TPO, it’s going to be a lot easier to maintain and repair than the one on their stationary residence. That may not be such a good thing for dealers, however, considering their most-likely involvement in the process will come from selling materials and offering advice.

Dicor President Gregg Fore stands in front of rolls of roofing materials that his company supplies to RV manufacturers. Dicor and Alpha Systems, both based in Elkhart, Ind., are the primary providers of rubber roofing materials to the RV industry.

Raising the Roof
When it comes to raising the roof on a standard RV, both EPDM (ethylene propylene diene monomer) and TPO (thermoplastic polyolefin membrane) are tried-and-true products, and both are big improvements over the aluminum roofs that were at one time an industry standard.

The more-mature product is EPDM. First developed in the 1960s, it made its initial appearance on RVs in the late ‘70s, according to Gregg Fore, president of the Elkhart, Ind.-based Dicor Corp., one of two companies that provides membrane roofing materials to the industry.

“Originally, almost all EPDM membranes were black, and on the commercial side of roofing they’re still primarily black,” Fore says. “The construction and use is entirely different than it is on RVs, not only because of heat management, but because I don’t think anybody wants a black roof.”

If anything, the RV industry helped lead the way toward lighter-colored EPDM roofs, which are gaining in popularity in commercial and residential uses because of the same heat-management issues.

Today, the EPDM roofs used on RVs come in a few colors, although not a huge color spectrum.

“Over time, different color ratios have developed, based on the different RV manufacturers’ desire to match the coloration of their units,” says Fore. “There was a time when we did a tan and when we did a gray. Now, we have a product called ‘dove gray,’ which is a lighter gray with a blue tint that in the sunlight looks more white.”

David Smith III, sales manager of Alpha Systems LLC, which is also based in Elkhart, Ind., and is the other leading supplier of membrane roofing materials to the industry, says his company has its own EPDM white, and is looking at a beige match, as well.

The story is similar for TPO, which arrived on the scene a little later. As its name suggests, it’s a plastic derivative, with all the positives and negatives that implies.

Originally used in the automotive industry for car roofs, its problems out of the box included severe coloration issues, including difficulties handling paint. Today’s better plasticizers have negated a lot of those concerns.

“In the TPO, we carry a gray and a beige, as well as white,” says Smith. “And, if there’s a situation where you want a different color, we have a painting procedure where somebody could take it to a body shop, use the recommended primers and have it painted whatever color they wanted.”

However, there’s a good reason for going with the white, Smith adds. Even with a gray or tan roof, sitting on a dealer’s lot that unit may be as much as 10 degrees warmer than a unit next to it with a white roof.

“If it’s that much hotter, you can feel the difference,” he says. “There’s no question it catches the attention of people who are concerned about cooling.”

In addition to being one of the leading suppliers of OEM roofing materials to RV manufacturers, Dicor is also a major provider of materials to patch and seal damaged roofs.

Weighty Issues
If heat issues have driven many OEMs to the lighter colored products – be they EPDM or TPO – there are other reasons that make the two products attractive to the industry. Certainly a big one is cost. The other popular roofing material on the market today is fiberglass, and Fore says that’s easily understood when people express the desire to have the roofs of their units match the walls. However, that comes at a cost – literally.

“Fiberglass is both heavier and more expensive,” says Smith. “If you’re buying a $350,000 motorhome, you can afford to put a more-expensive roof on it. If you’re buying a $15,000 travel trailer, you probably can’t.”

Fore estimates a fiberglass roof is about three times more expensive than a membrane one, and he says the fiberglass isn’t without its problems, too. A big one is thermal expansion and contraction.

“The fiberglass used on roofs is so thin that if it gets stressed in installation – which you may or may not know about – it can develop hairline cracks because of its stiffness,” he says. “It appears to work best on flat-topped motorhomes.”

The reality is that fiberglass doesn’t have the elasticity that allows it to take compound curves very well, creating almost impossible installation problems, especially on towable units.

It’s that elasticity that gives EPDM its edge for some designs over TPO.

“TPO has more thermal expansion than EPDM,” says Dicor’s Fore. “That means it’s not as pliable as EPDM, making it more difficult to install, although not in all applications. Some of that has been minimized over time with chemistry. They both perform weather-wise very well.”

However, Alpha’s Smith notes that TPO does have a different attribute that gives it a leg up over EPDM in one area: overall operating costs.

“There are some weight differences,” he says. “TPO is about half the weight of the EPDM. You can save about one pound-per-lineal-foot, which translates into gas savings. You might not see it up front, but you will on down the road.”

For all those reasons, the choice of roof material used on a particular design rests with the OEM and not with the RV buyer.

OEM roofing materials are available in a number of color options, including gray, beige and tan. Still, white tends to be the most popular color selected by RV manufacturers.

“It’s definitely a matter of the OEMs saying, ‘This is what we buy for this model,’” says Smith. “The end user isn’t going to dictate what’s on the roof. However, some manufacturers use EPDM on some models and TPO on others; it depends on what their design needs are.”

Fore says there are a few manufacturers who will roof depending on a dealer’s preference.

“They’ll use either fiberglass or TPO, based on what the dealer orders – at least on some units,” Fore says. “A lot of times, though, people don’t get the choice.”

And, he adds that most buyers don’t know what sort of a roof system they’re getting until either the dealer uses it as a selling point on the lot, or the new buyers sit down to read the warranty, although the warranties for both EPDM and TPO are currently 12 years.

“Today, the warranties for all the roofing materials (including fiberglass) are probably comparable,” Fore says.

Option/Not an Option
So, beyond using it as a selling point, where does that leave the dealer when it comes to these systems? Despite that 12-year warranty, Fore says there are a lot of situations where a new roof – or roof repair – is needed.

“Certainly, selling to the OEMs is the larger part of our market, both for EPDM and TPO,” he says. “However, probably 15 years ago, we determined there was a reroofing market that comes from a lot of places.”

Initially, Fore says a part of the replacement market came from people with older, aluminum roofs that were damaged, often by weather. Today, there are still accidents, and people who don’t take care of what they have.

Alpha’s Smith estimates that probably 95 percent of previous roofing problems have been eliminated from today’s systems. Occasionally, an issue will come up with installation.

“We do audits as a company at the manufacturing plants, and Dicor does audits as a company,” he says. “These things aren’t always installed in the same way.”

While an errant tree branch can sometimes be to blame, both Fore and Smith agree that the biggest culprit post-manufacturing is lack of maintenance by unit owners.

“Once the consumer buys a unit he should plan on getting up and checking the sealant a couple times a year,” says Smith. “I’ve seen bugs get in there and really pick away at it.”

“Every product is going to react differently once it’s exposed to the elements, and people take their RVs into a lot of different environments,” says Fore. “However, a lot of maintenance is just simple cleaning on a regular basis.”

And, when Fore says “simple,” he means just that. Although both companies offer cleaning products, the easiest approach to roof cleanliness is plain old soap-and-water.

Smith, in fact, says nothing stronger than a product such as Murphy’s® Oil Soap should be used on an RV roof, although Fore says something a little harsher might be needed if the unit is in environments where the air collects a lot of pollutants.

“The caulking is primary,” says Fore. “That should be checked a couple times a year. As for the cleaning, some people probably never clean it. And, some of these units are parked in a campground under trees all year, and then they wonder why the roof is dirty.

“There’s no firm measurement you can give to everybody, but owners need to take a common-sense approach.”

Trees aside, Smith says the other best thing RV owners need to be told about their units is to store them in a covered location — if possible.

“If there’s a crack in the skylight or you rip the roof and don’t know it and it sits under snow all winter long, you’re going to have a serious problem when you pull out in the spring,” he says.

Of course, maintenance isn’t going to keep a roof going indefinitely, and for times when problems arise, “I always recommend taking it to the dealer,” Smith advises. “Not that the dealer needs to fix it, but he can point the owners in the right direction and make sure they have the right patch kit. And, that way they can make sure there’s no damage outside of just what they can see.”

He adds that if the entire roof needs to be replaced, it still isn’t a complicated process, although a dealer might be better off doing the work because of the need to take off vents and other items.

Fore agrees. He says while the work isn’t difficult, a dealer might be in a better position to identify places where the roof might be pulling loose, for instance. Dicor operates a customer service hotline for both dealers and RV owners, and if there are any questions about how to best approach a problem, the company would appreciate a call.

“We’d rather talk to them before they do it their way and want us to fix it,” Fore says. “And, we’d like dealers to tell their customers that – just as with everything else they own – when it comes to the RV roof, maintenance is not an option.”

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