Roofs

Rubber Roofs - by phred Tinseth

Dicor Corp. makes most of the EPDM (Ethylene Propylene Diene Monomer) material used in so-called rubber roofs. (Dicor calls it Brite-Ply.) Literature is provided with new RVs. Most people never pay attention to it, if the dealer even bothers to pass it on. Used RVs also seldom have the information.

A critical point:

It is critical that no petroleum-based solvents, harsh abrasives, or citric-based cleaners be used on rubber roofs. Doing so can cause irreparable damage. (And seems to be the real cause of most roof complaints, followed closely by sloppy installations.,)

Petroleum-based solvents are especially damaging. They can penetrate the membrane and dissolve the adhesive underneath. The result can be bubbles or even large, loose patches.

Bubbles:

Bubbles should generally be left alone, unless there are a great many of them, which indicates a more serious problem (like extensive use of petroleum products or a poorly installed roof).

Photo by RVCG Staff Photo by RVCG Staff

Dicor makes the material. They do not apply it to the RV. The RV manufacturer (in some cases RV dealers) do that. The EPDM membrane, as supplied by Dicor, should last 30 or so years (possibly longer than you will), if properly installed and taken care of.

Most blisters are small, few in number, and are only cosmetic. Since they are on the roof, they are not all that visible. Cutting slits or poking holes in them and injecting sealer or caulking can lead to water leaks and further damage. If they are left as is and not carelessly torn, you are usually better off.

If you insist on fixing bubbles (and you shouldn't), make sure you use only sealers that specifically state: butyl rubber caulking/sealant. There are a lot of sealers, caulks and care products that have something like "Okay for rubber roofs" on the label. Do not accept that as a fact.

Insist on butyl rubber ingredients for sealers and caulking.

When attempting to fix (flatten) bubbles, don't just start cutting away. Get some disposable medical syringes from a pharmacy. Load one with some of the butyl rubber sealant, carefully inject some and carefully massage the bubble. Once it's flat (this can take a lot of massaging - hey, I warned you), put a piece of cling wrap or wax paper over it and put a weight on it until dry. You might or might not be successful.

One place you can successfully use the butyl rubber sealant is at the edges of the roof membrane. Roof vents, plumbing vent pipe holes, roof edges under trim strips, air conditioner openings, etc., are all subject to loosening at the membrane's edges. (This is often caused by a sloppy installation.)

Refrigerator roof vents are especially troublesome. Installers often cut the opening through the membrane rather casually. They then fold it over the edges of the vent hole and don't adequately secure it. Over time, and with the heat that flows up through the vent, air flow can be restricted (and it doesn't take much to cause the all-too-common complaint that the reefer isn't cooling properly).

RV manufacturers frequently do an absolutely lousy job of installing refrigerators. Poor ventilation is (experts say) the primary cause of refrigerator failures. I recently heard of a refrigerator ruined because the manufacturer simply cut a hole in the roof over a reefer and let the rubber-covered plywood drop on top of the reefer. No venting equals no reefer. You might want to see what's really under your roof vent.

Maintaining the rubber roof:

  • Mild dishwashing detergent should do the job unless you're parked under really grody trees. Use a mild-bristle brush. Do not use harsh abrasives or a stiff brush. A sponge is okay for scrubbing, but a brush is needed when rinsing. (Using a sponge when rinsing just smooshes the dirt around and doesn't get rid of it.)

  • Full-strength household bleach is good for stubborn stains (but don't slop it all over, or it will run down the sides and mess up your wax job).

  • Dicor makes a safe cleaner. Their RC100 Dicor Synthetic Roof and General Purpose Cleaner works and attacks stubborn stains when used full strength.

  • Mineral spirits can help with stubborn stains, but you can't spread it over large areas and must work very fast (spot clean and flush it off quickly) or it can deteriorate the membrane.

  • ProtectAll makes a cleaner and surface treatment that is supposed to do a good job but, if I'm not mistaken, it contains petroleum solvents. I wouldn't use it without further checking. (See the Dicor info.)

  • Another good protectant is 303. It will not harm rubber roofs and will keep crud from accumulating, but, Dicor insists it isn't really necessary.

Something to think about then:

A word often used in discussing rubber roofs is "if." As in rubber roofs can be dandy:

  • If the basic structure (rafters, etc.) is sound.
  • If the ply underlayment is sound and of adequate thickness.
  • If the rubber sheeting is carefully laid on without gouges, cuts, etc.
  • If done without careless trimming around things that penetrate the roof.
  • If done without any nail/screw heads/wood splinters and such left so that they'll eventually penetrate the rubber from the underside, etc.
  • If rubber adhesive is properly applied so bubbles won't appear later and edges won't come loose.
  • If rubber material is properly folded over roof edges, carefully trimmed and moulding is properly applied.
  • If the RVer doesn't screw things up by gouging, scraping, etc.
  • If the RVer uses the specified mild-detergent cleaning agents and never uses a petroleum-based cleaner or protective coating.
  • If the RVer reads the material that accompanies the roof and understands that there will be discoloration of the roof, which won't hurt anything.
  • If the RVer understands that minute particles (dust) from the roof membrane will flake off, and combined with water, will make some dirty-looking marks on the RV which are easily washed off.

After-Market Kits to "Recoat" a Rubber Roof:

The kits available to do this will cost at least several hundred dollars ($700 or more?) from RV supply stores. You'll have to remove everything on the roof to do the job properly, or you'll have all the loose edges, untreated areas, etc., as discussed above. If you don't do the job properly, you'll have just thrown away that several hundred dollars. Preparation of the existing surface is exhausting and must be done properly. A minimum of four coats (of various substances) is required -- yet more hard labor -- and they all have to be done right.

Photo by RVCG Staff

If anyone is considering "resurfacing" an existing roof with "paint-on" stuff, I suggest you first check with a shop that can remove the existing "rubber" cover and install a new one. If you're a careful shopper, you may find that a shop can put on a new roof for only $200 to $300 more than your resurfacing "paint" job. I don't know about you, but it seems cheap to me considering all that's involved.

 


Good roof, sealed well.
Photo by RVCG Staff

In summary:

Rubber roofs are not cheap. They require care. If installed and maintained properly, they can be very nice and almost leak-proof. The material will flex just slightly with temperature and weather and may (should?) last the life of the RV. However, any deviation from any of the above "ifs" can be a real problem.

Hitcharama RV in New Jersey uses a product called "Reliable Cleaner" for all their coach preparations. It contains Glycol-Butyl-Ether, Non-ionic Surfactants, Sodium Metasilicate, and is water-based. Might be okay?

You can get information sheets from Dicor Corp., PO Box 1806, Elkhart, IN 46515. 219-264-2699. Best way is to use their website at www.dicor.com for much more extensive and timely information.

Bonus stuff:

While lurking around the back room of a place that does rubber roofs, look for fairly large scraps of the membrane. It makes excellent gasket material for water pumps and sewage macerators. It's good for covering sharp edges and inserting between things that rub together. It maintains its flexibility and is good for use as a flap over outdoor electric receptacles and leaky upper hinges on storage compartments.

Editor's Note: This article was reprinted with permission from the author, phred Tinseth, who has a website at http://www.phrannie.org full of practical advice and comments for RVers. His articles appear frequently in Escapees RV Club Magazine.

   Return to RV Reporter

RV Reporter is a publication of RV Consumer Group. © 2001 RV ConsumerGroup.