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The Truth About EPDM Rubber Roofs

The Truth About EPDM Rubber Roofs

Approximately 75% of all Recreational Vehicles now manufactured have EPDM Rubber Roofs. Because of the advent of 'rubber roof treatment' products in the last few years, the tremendous amount of mis-information and lack of understanding about this material and it's proper maintenance, 303® Products, Inc. and Dicor Corporation (a leading supplier of EPDM roofing material) have recently published a public service announcement which details the facts...important information RVers need to know.

This month's Cover Story reproduces the introductory portion of this announcement. Frequently asked questions about EPDM rubber roofs and Dicor's Care & Maintenance instructions will be reproduced in next month's cover story.



* EPDM RUBBER: What it is and why it lasts so long.

* PROPER CARE: What manufacturers actually recommend.

* WATCH OUT! For RV products that can damage EPDM rubber and void your warranty!

* How to keep your EPDM rubber roof clean and looking like new


EPDM is one of the most versatile and long lasting materials ever manufactured for outdoor exposure. Most RV industry experts consider EPDM rubber roofing membrane the most dependable, most cost effective and easiest to maintain roofing material there is. Yet today's average RVer is deluged with information, a great deal of it mis-information, about rubber roofs. Consequently, RVers are spending millions on unneeded products, many of which may be harmful to EPDM rubber roofs. 
This Public Service Announcement details the truth about EPDM and reprints manufacturer's guidelines on cleaning and maintaining the EPDM rubber roofing membrane on your RV. If you have questions after reviewing the material, please contact Dicor Corporation, the RV industry's largest supplier of EPDM rubber roofing. Dicor's address and phone numbers are provided.

Mis-Information, Mistakes & Money 
EPDM stands for Ethylene Propylene Diene Monomer. Engineering specifications describe EPDM as "Ideal for outdoor applications because of its excellent resistance to ultra-violet light, ozone, oxidants, and severe weather conditions."

EPDM rubber roofing membrane is made to last 20 years or longer and has a 10 to 12 year guarantee depending on the brand. The guarantee does not require the use of any protective `roof treatment' or `roof protector' product and recommends only cleaning. Unlike natural rubber (latex) or rubber blends (tires & wiper blades), EPDM does not require periodic applications of any product to protect it from ultra-violet light or ozone.

The statement or implication that you should purchase and apply a product to "protect" your rubber roofing from the elements is mis-information. Buying and using such a product can be a mistake and may even damage the EPDM membrane.

Petroleum distillates - Not For EPDM
Petroleum distillates are incompatible and should never be used on a number of plastics...vinyl, most rubbers and particularly EPDM. Engineering specifications for EPDM rate its solvent and oil resistance as "POOR". DICOR's Care & Maintenance instructions warn: "CAUTION: DO NOT use cleaners or conditioners containing petroleum solvents, harsh abrasives, or citric based cleaners. You may cause irreparable damage to your roof".

One of the mildest of solvents is mineral spirits, and DICOR even warns against this: "DO NOT use mineral spirits in a large area or allow it to soak into the membrane."

Laboratory tests conducted in July of 1996 evaluated the effect of a leading RV "roof treatment" product on EPDM roofing membrane using standard sunlamp and immersion testing procedures. The "roof treatment", which contained petroleum distillates, caused a 63% mass change (swelling). In the summary/recommendations portion of the lab test the scientist noted they would not recommend the "roof treatment" and perhaps more tellingly noted, "Per the MSDS, this product contains petroleum distillates, a substance that is known to be incompatible with....EPDM sheeting".

For your rubber roof, for the EPDM seals around slide-outs/ pop-ups, in the baggage compartments or for the EPDM door and trunk seals in your car, petroleum distillates are a huge "No No". And don't be fooled by names such as "organic solvent", "hydrocarbon carrier", etc. Petroleum distillates by any other name should NEVER be applied to EPDM. If you aren't sure about a product, contact the manufacturer and have them send you a copy of the Material Safety Data Sheet (MSDS). Look under the section entitled "HAZARDOUS INGREDIENTS". If it lists any petroleum distillates, do not use it on EPDM.