Dicor Issues Technical Report on Rubber Roofs

August 17, 2011 by · Comments Off on Dicor Issues Technical Report on Rubber Roofs 

Editor’s Note: The following is a technical report from Dicor Corp. outlining care and maintenance for RV rubber roofs, a core product line for the Elkhart, Ind. company

Taking care of your RV’s rubber roof

Rubber Roofs are the number one choice for today’s RVs. More than 2 million RVs with rubber roofs are presently on the road. Rubber roofs require less lifetime maintenance; they eliminate “roof rumble,” and have passed the ASTM (American Society for Testing and Materials) 20-year accelerated aging test. First introduced commercially in the 1960s, rubber roofs started to become popular in the 1970s and by the 1980s accounted for 40 percent of the roofing market. Today rubber roofs account for upwards of 70 percent of RV roofs.

EPDM (Ethylene Propylene Diene Monomer) is one of the most versatile and long-lasting materials used for RV roofs. It is cost effective and both easy to maintain and repair. EPDM provides excellent resistance to ultra-violet rays, ozone and oxidants, while performing well under severe weather conditions.

Care and Maintenance

Care of a rubber roof begins with prevention: be aware as to how damage may occur. For example, EPDM roofing membranes are specially formulated to be more puncture resistant, yet these materials can still be cut or punctured by sharp objects. Also use caution when placing any articles on the roof, walking on the roof, or parking under low hanging tree branches. Beware of areas where fruit, tree sap, or harsh environmental fallout may stay on the roof for an extended period of time. These conditions may result in permanent stains. If your roof is exposed to such conditions, you may need to increase the frequency of your roof cleaning.


Caution: As with the surface of any roof, a rubber roof can be very slippery, especially when wet. If you go up on your roof we recommend extreme caution and suggest that you navigate the roof on your hands and feet. This distributes the weight more evenly and helps reduce the possibility of falling.

Dicor Products recommends that a rubber roof be cleaned at least four times annually. Use the following steps:

1. Completely rinse your roof with clean water to remove any loose dirt or debris.

2. Use a medium bristle brush and a concentrated cleaning agent such as Dicor Products RP-RC160C, mixed with two or three gallons of water. As an option to the concentrated cleaning product, Dicor also has a ready-to-use roof cleaner: RP-RC320S. Work in small manageable sections such as a 3’ X 3’ area starting at one end and working toward your point of exit. Scrub and rinse with clean water thoroughly to avoid residue build-up on the roof or sidewalls of your RV.

3. For difficult areas repeat step 2.

4. Caution: Do not use petroleum distillates to clean the roof as they may cause permanent damage.

Roof Protection

With a newly cleaned roof, now would also be a good time to add a roof protectant product such as Dicor Products’ well-known Roof-Gard RP-RG320S UV protectant. This type of protectant is mild and non-abrasive and helps minimize oxidation, as well as drying and cracking, and leaves a finish that repels dust and water. It helps reduce fading from UV rays and keeps surfaces cleaner longer without residue or oily build-up. It’s also free of silicone oils, waxes, glycerin and petroleum distillates, all of which can harm a rubber roof.

To use, first clean the roof. Then while not in direct sunlight, spray the Roof-Gard protectant onto the surface. To ensure even coverage, apply in manageable sections such as a 3’ X 3’ area using a damp sponge mop or soft cloth. For maximum protection, apply every 3 to 5 weeks or as necessary.

Restore It!

Over time, just like everything else, your roof will show signs of aging. However, you can extend the life of your roof for years to come with Dicor Product’s 2-Step restoration system. This 2-Step Rubber Roof Coating System combines a cleaner/activator that in one step cleans and prepares the surface and helps promote adhesion of the unique specially formulated EPDM rubber roof acrylic coating. This provides a protective shield o help extend the life of the membrane. This is recommended not only for older roofs, but any roof that is tired, dirty or stained.

Caution: It is important to NOT use cleaners or conditioners containing petroleum products, hard abrasives, or citric-based formulas. Use of these products may cause irreparable damage to your roof and/or void the warranty.

Additionally, you may need a lap sealant to touch up or replace existing lap sealants around roof protrusions such as vents, skylights and trim strips. If the old lap sealant has pulled away from the roof, remove it and reseal. If the lap sealant has only surface cracks, just seal over. A cloth dampened with rubbing alcohol to eliminate foreign material from the seal provides a good prep for the new sealant. Be sure the area cleaned with alcohol is dry (about 15 minutes) before putting on the new lap sealant.


Damage may be in the form of punctures and/or rips.

For heavy-duty repairs, i.e., those with extensive damage, use Dicor Products 533RM available in 6-inch or 12-inch widths by 25-foot lengths. This is a peel and stick repair material. For smaller repairs, Dicor Products recommends DiSeal RP-TPO451C. This is a 4-inch X 50 -foot roll of peel and stick self-adhering repair material. For very small punctures Dicor Products offers a 6-inch X 6” patch of peel and stick material RP-TP066-1C. Dicor also supplies an emergency patch and repair kit that you can take with you, the 402PR.

To repair a puncture or rip, examine the area to be repaired and clean the area with Dicor Products rubber roof cleaner; rinse thoroughly. Ensure the roof is completely dry, Then, using a soft cloth dampened with rubbing alcohol, clean the dampened area again. Let dry thoroughly. Cut the repair membrane to extend over the hole making sure it overlaps the damaged area by 2 inches on all sides. DO NOT use multiple patches for a single repair: use the correct size. It is important to position any patch on the first try as the patch should not be lifted and repositioned.

Frequently Asked Questions

Is it necessary to protect my rubber roof against UV Rays?

No. But Dicor Products Roof-Gard will add additional protection against damaging UV rays

If I use a roof treatment product containing petroleum distillates on my rubber roof, will that void my warranty?


If I buy a used RV and it has a rubber roof, how can I tell if the previous owner used petroleum distillates and damaged the rubber roof? What should I look for?

Two things: First, swelling and uneven thickness of material. Second, loose areas. Petroleum distillates soak in and cause the adhesion to loosen and the membrane to balloon. When the ballooning goes down, the membrane may never adhere properly or completely.

My roof seems to “oxidize” and run down the sides when it rains. Is this normal?

The simple answer is “Yes.” EPDM does oxidize slowly; it is supposed to. This is normal. By oxidizing, your EPDM rubber roof is protecting itself from damaging UV rays. Over the lifetime service of your roof this oxidation process claims about the thickness of two sheets of notebook paper. Cleaning the roof at least four times a year, or more often if necessary, will help greatly.

Is it easy to repair tears in the roof membrane?

Any tear in an EPDM roof membrane can be repaired using a number of repair methods. Dicor Products offers a prepackaged peel and stick repair kit (402PR) that works well on small tears (up to 8 inches), as well as a larger kit that should be used on large damaged areas (533RM-6 or 533RM-12). For longer tears use repair kit, 522TPO-450-1C.

One supplier of cleaning products told me that their roof treatment had only a very small percentage of petroleum in the neighborhood of 10 to 30 percent. Is a small percentage like that OK to use on my roof?

No. Usually the percentage is given based on weight. Since petroleum distillates are significantly lighter, the reality is that 30 percent by weight might be 40 percent or more by volume! THERE IS NO LEVEL OF PETROLEUM DISTILLATES THAT IS RECOMMENDED.

Note: Dicor Products Lap Sealant contains a type of petroleum distillate used strictly in the curing process. At the Lap Sealant cures, the petroleum distillate evaporates. This will not harm or cause permanent damage to your roof.

The rubber roof wraps over slightly on both sides of my RV and you can see it from the ground. Is there any special care that I need to follow for this part of my roof?

Clean the area and treat it with a product that will repel soiling and is safe for EPDM. One product that performs well, lasts long and is safe for EPDM and is commonly available at RV stores is Dicor Product’s RP-RG320S Roof Gard and Protectant.


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