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Roofs
Questions / Answers Q: My motor home has a rubber roof and I am tired of cleaning it and putting up with the chalking and general mess. Do you feel the fiberglass roof is superior to rubber? How about aluminum? Paul Stakun, Connecticut A: A rubber roof can be forgiving to design and workmanship and, provided it is well glued to the underlayment, it should be trouble-free and long-lasting. The rubber roof must be well-domed for water runoff. Likewise, a well-domed molded fiberglass roof should give few problems if the roof accessories are well sealed. The aluminum roof must be thick enough so that it won't buckle, is well sealed, and allows for water runoff.
Q: We have heard from owners and RV salesmen that fiberglass roofs are far superior and that, in particular, rubber roofs cause streaking on the side of the coaches because dirt tends to accumulate on rubber roofs more than on fiberglass. Is this true? Mel Silverstein, Massachusetts A: Only partially, Mel, fiberglass roofs are sometimes superior if they are well-designed and forgiving to sloppy workmanship during the installation process. A well-domed fiberglass roof to which all the roof-mounted accessories are attached can leak if not attached correctly. Rubber roofs are user-friendly to accessory attachment due to the cushioning effect that acts as a sealant. Finding a "firm" spot such as cross members or extra thick underlayment is the secret to attaching accessories to these roofs.
Q: The aluminum roof on my 1985 Mallard fifth wheel needs to be resealed. The joint sealer on the seams and around the vents is shriveled and separating from the seams. I don't want it to leak and it doesn't look like the roof has had any regular maintenance. How do I remove the old sealer and where can I locate a quality sealer to utilize? What type of sealer should I be wary of?
Luke Madrinich, Minnesota A: If this roof is, as we suspect, a multi-piece crimped-seamed roof, you will find potential leaking mostly around the vents and possibly where the seams meet the edge of the roof. In any case, the first thing you must do is remove as much of the old sealer as you can from the roof. An experienced roofer might use a slight amount of heat from a torch to make the removal process easier, but we don't recommend this process for most people. It will simply take a strong scraper that won't cut into the aluminum and get every bit of the loose sealer removed. The second thing is to use some sort of sanding paper, then you should buff where you are going to apply the new sealer and clean with paint thinner or some other nonfilming solvent. Third, there are good sealers at every RV supply center (absolutely do not use any silicon sealer). You must feather the new sealer on carefully in at least two applications, although we prefer three applications. On a seamed roof, it is generally not required to seal the cross-seams, especially if they are double-crimped and appear flat and without signs of leaking. Be especially careful to seal around the vents - in some cases you might have to remove the vents and put some new sealer between the vents and the roof.
Q: Which is the best roof system for a Class C motor home? Tim Stieve, Wisconsin A: The best roof is a roof that doesn't leak. Except for the one-piece "thin" aluminum roof, the other roofs are pretty reliable depending upon design and workmanship. Let's face it, some manufacturers can put on the best roof and it will still leak. Rubber roofs, fiberglass roofs, and heavy-duty aluminum roofs have all worked well when applied by a good manufacturer. Most class C motor homes are using EPDM (rubber) roof coverings because of economy and ease of installation. Some more expensive class C's are using full fiberglass caps. And we even have one of our best-rated manufacturers using aluminum covering without any record of leaking. Very simply, Tim, stay with the reliability rating and you should be OK.
Q: I noticed that the roof covering behind the fiberglass and caps are not firmly attached in all areas to the underlayment. It appears that there is a gap between the underlayment and the covering. Should this be sealed firmly to the underlayment? There is no leakage occurring, I just noticed some raised sections about 1/16" above the surface.
Jim Voos, California A: A good quality sealer is made specifically for this purpose. More importantly is to clean the roof and then apply at least two thin applications of the sealer. Absolutely do not use silicone seal. To do a good job, plan on at least a good part of one day.
Q: We bought a 1997 Sahara. The previous owners told us the roof buckled in Texas in 100 degrees heat. We have checked it closely and see no roof leaks. Is this a concern for the long term life of the roof on the motor home?
Barbara Hart, Oregon A: Safari products have had a history of pooling and thus leaking, Barbara. This is primarily a design problem. You can live with this deficiency by very carefully sealing the roof at least every two years. This is a must if you suspect problems.
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RV Reporter is a publication of RV Consumer Group. © 2001 RV ConsumerGroup.