All You Need to Know About RV Roofs

1 Comment 29 March, 2011, 14:40

Hey it’s raining outside! “Oh no! My RV roof has a leak!”

How about a quick refresher course on roof leak repair and where to look for problems? If you own an older model camper with a metal roof you can use just about any of the numerous RV or mobile home roof sealers on the market.

At all cost, please stay away, far away, from any tar products. They do not work for any length of time and are impossible to remove. Remember, rubber roofed campers all require sealant formulated especially for rubber roofs. NO silicone, kool seal, polyseam seal, dyco. Nothing but approved rubber roof sealant should be used. (Like the one listed at the end of this article.) These sealants are mostly self leveling caulking in nature and are only to be used on flat surfaces as they will run until fully cured.

Now, let’s talk leak location. The front and rear seams on your roof cause the biggest problems and usually, we find the most problems at the extreme ends. If your roof has leaked for a while, the wood under the rubber might be weak and thus, unable to hold the joint molding securely to the roof. No amount of caulking will hold this molding down now, you must first remove the old caulking and replace the old screws with longer ones to try to find good wood.

This may also involve new screw locations between the existing screws. At the extreme ends within 2″ of the outside wall there are two 2″ X 2″ boards stacked on top of each other. One is the top of the wall and one is the roof beam. At this location it is possible to use as much as a 3″ screw to secure the molding. Apply caulking under the trim before securing and then coat the complete top. One seam caulked correctly will use approximately two tubes of caulking. You will need a caulking gun to apply this type of sealer, and rubber roof caulking can only be purchased at an RV dealer or parts supplier.

With so many of the newer campers having slide-out rooms, these movable rooms are notorious for leaks. Most of the leaks located in slide-out rooms happen in two locations. The first is at the outside corners of the leading edge where the rubber roof folds down over the side and up the front, which creates an opening right at the outside corner. You can’t fold one piece down and the other up and be able the overlap the roof material. Look at this location first for all possible slide-out room leaks as water will travel and show up no where near the actual leak. The other popular location is at the lower outside corner closest to the camper. To access this location, look behind the rubber wiper seal. This location can, and should, be caulked with silicone.

Take your time looking for leak locations. The slightest crack will allow water to penetrate and, if the location has been repaired once before, remove old material before applying new. The RV industry has developed many ways to locate leaks if you are totally unsuccessful, so don’t let that leak destroy you camper. Get it fixed at all cost.

When the rain finally stops, bolt outside and look inside your camper. And when the water finally recedes, what do you say we all go camping?


Different types of roofing materials are used on RVs, and certain products are to be used on certain materials to safely seal and maintain your camper’s roof.

Metal & Fiberglass Roofs

Metal roofs are probably the oldest and most popular for campers. Be it aluminum or galvanized metal, the products to maintain these roofs are the same. Units having a fiberglass roof structure should be maintained in the same manner, using the same products as metal roofs. We use Dyco 20/20 seam seal on all seams and around roof vents, antennas, vent pipes, etc., that protrude through the roof metal.

(Never seal around a roof A/C unit, as the condensation drains are located underneath and seal will cause the water to drain inside the camper. If your A/C unit leaks during a rain storm, replace the A/C gasket.)

Sometimes, it is necessary to coat the whole roof. If so, wait 24 hours after applying Dyco the protruding pieces, then, using a medium knap paint roller, roll two coats of Kool Seal elastromeric sealant over the remaining uncoated area.

(Under no circumstances should you apply roofing tar to and RV roof, as it typically will not correct a leaking problems and makes it impossibly to apply a sealant that will work without first removing the tar.)


EPDM & TPO Roofs

Newer built RVs will have either EPDM rubber roofing material or TPO (thermoplastic olefin) roofing material.

EPDM roofing requires a semi-annual cleaning. (Some manufacturers suggest four times a year.) Use one of the following non-abrasive, non-bleach containing products: Spic-N-Span, Top Job, or RV rubber roof cleaners made by Dicor, Protect-all or B.E.S.T. products.

Along with semi-annual cleanings, you should also treat your rubber roof with a UV blocker that will aid in reducing the dreaded black streak/white chalking problems that occur with roofs that are not maintained properly.

Any resealing required on a EPDM rubber roof can only be accomplished with an approved EPDM sealant. These are available in either a self-leveling form (only use on flat surfaces), or non-leveling form made by Dicor. Do not use silicone or any other sealants not designed for EPDM. They will not adhere, and void any manufacturer’s warrantee.

There are a couple of complete roof coatings available for EPDM roofing, but in my past experience, I felt they did not perform well, or accomplish the results the customer was expecting. If you feel this is your only way out of an expensive total roof replacement, Dicor offers a roof renew kit ($570) that includes complete instructions and a five year warranty if applied correctly.

TPO roofing requires no semi-annual cleaning or treatment, but regular washing will aid in keeping the sides of your RV clean. Any sealants needed on these roofs also must be designated and formulated for EPDM and TPO materials.

Remember, all sealants are only as good as what’s under them. A rule of thumb is two applications, then it usually becomes necessary to remove prior caulking and start over with the correct type of sealant for your camper’s roof.

Replacing Your RV Roof Vent

All motor homes and travel trailers are equipped with some kind of roof venting system, the most common of which is the manual crank up version. Although relatively trouble free, these units – just like most things on an R.V. – require maintenance. Semi annual inspections of your total roof should detect the need to reseal your roof vents.

The most common mistake made with the R.V. roof vent is not replacing the cover often enough. If the shine is gone or the plastic is chalky to the touch replace the cover now. Trust me, it will disappear at the most inconvenient time, leaving the vent open after you are done with your camping trip or away from your camper for an extended length of time (you know this is when it rains the hardest).

Roof vent covers are produced by a number of manufactures; each using a different hinge attachment system. To insure the proper vent cover replacement is purchased, first look on your unit at the trim work or the crank handle to locate a manufacturer’s name. If it isn’t there, take careful note of the vent’s hinge system. The hinge can only be viewed from on top of your R.V., so please be careful.

Replacement covers made of plastic cost about $16.00 each, and some manufactures offer a metal cover $22.00 each (Note: no light infiltration.). A life-time warrantee cover is available from most vent manufactures for about $25.00 each.

A vent over cover is a great investment. This will enable you to leave the vent open all the time, helping to prevent mold, excessive heat build up, and persistent stale odors all without the possibility of water damage due to a sudden rain storm (or your neighbors sprinkler system). These covers also protect from sun damage and come in a variety of styles and colors from the simple $27.00 unit to the wireless remote controlled 4-speed reversing fan with thermostat $379.00 unit.

There are vents that open and close automatically according to temperature, turn off and on a fan as needed, and when a sensor located on top of the vent gets wet — will close the cover for you. With endless possibilities all to fit your budget and needs the days of the simple crank it up crank it down vents are properly numbered.

To change the simple cover however, start by removing the trim ring, the crank handle, the screen assembly and the opening and closing operator all located inside your R.V. A screwdriver should do it. To remove the cover assembly, proceed to the roof again depending on the hinge your vent has (remove the screw, bend the tab, etc.) slide the cover left or right to remove. This is when you realize how important it was to be neat with your sealant when you applied it. Slide the new cover in place, return to the inside and reassemble the components you took apart. Check to make sure the cover opens and closes correctly before putting all your tools away.

After installing a new cover, check for water leaks around the vent, either by applying water with a water hose. A small leak over time can cause major damage to your R.V.

As always, I hope this helps you in the maintenance and enjoyment of your camper. May God Bless.

Roger White, owner of Roger’s Mobile R.V. Repair, has been serving the RV Industry for 30 years. If you need assistance with these procedures or any other problems with your RV, he can be reached at 304-364-4260. Roger is located in Gassaway, WV.


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Comments (1)

  1. Monty Germaine 31. March, 2011, 5:03 pm

    Inspecting your roof before you leave for a trip is always a smart idea! There are a lot of other things that need to be inspected to ensure a safe trip. The best way to ensure that everything is in proper working order you should have a professional inspection performed. It can save you a lot of trouble down the road.

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