Rubber Roof Care and Protection

Cleaning your rubber roof does not have to be one of those dreaded chores that you worry about having to do for days and weeks before you force yourself to finally do it. Of course, you could think like those RVers who justify not doing it at all by saying, “No one sees the roof so why clean it!” Sort of like out of sight, out of mind. But, most of us just grit our teeth and finally get to work. Before discussing how to maintain your rubber roof membrane as quickly and as easily as possible, it would be best to point out some of the EPDM rubber material’s properties and characteristics.

Drawbacks of EPDM roofs

Although a very reliable material, EPDM does come with some disadvantages. Rubber roofs are fairly porous in nature, which means dust and particles will collect in time. Some of those particles are microorganisms called fungi which develop into mold and mildew in the right condition. The white color chosen for most rubber roofs is because it helps with better regulating the temperature in the RV during summer. The side effect of having a white roof is that it doesn’t absorb enough heat to generate surface temperatures above 126 degrees, necessary to prevent the mold and mildew from developing.

To have a mildew problem, four elements are needed. This is referred to as the Mildew Square. In order for mildew to proliferate, spores, food, warmth and water must be present. The EPDM and/or TPO roof left dirty and damp is a perfect host. Microorganisms require a source of energy, carbon for cell structure, nitrogen for amino acid synthesis, essential minerals and water. Eliminate one of these elements and the square is broken, the mildew problem is eliminated.

The spots that develop on the RV roof are a byproduct of the fugal digestion process. These organisms are ubiquitous; they are everywhere, spreading their spores in the wind. Since this type of growth forms easiest in the presence of moisture, the spots appear to be more common in wet and humid climates. Here the roof becomes a hospitable living environment. Plenty of water and warmth and the spores take hold.

With some effort and a good cleaner, some of these stains can be removed, but most will never come off the roof, no matter how hard you try.

One recommendation from within the industry is to use a solution of bleach and water. Our tests and comments from many RVer’s indicate that this cleaning method is most often unsuccessful.

Another recommendation is the use of petroleum distillates Xylene, Toluene or Mineral Spirits. Although these are good cleaners, they do not remove mold and mildew spots with any consistent success. Since these cleaning solutions contain harsh chemicals, do not soak the surface. Dampen a rag with the distillate and wipe the stain.

Preventive maintenance

Breaking the Mildew Square is the best measure of preventing the fungus growth. Since it is not feasible to physically dry your roof every time if gets wet from rain, morning dew or humidity, the next best method of breaking the Mildew Square is to eliminate spores, food and warmth, the other three essential needs of mold and mildew growth.

Keeping the EPDM rubber roof material as clean as possible will help to accomplish this. Start by thoroughly cleaning and treating your rubber roof three to four times a year with Protect All’s Rubber Roof Cleaner and Rubber Roof Treatment.

In addition to helping to retard the chalking process described earlier in this article, Protect All Rubber Roof Treatment aids in keeping dust, pollen and other airborne contaminates that settle on the roof, from sticking to the rubber surface. Then, every week or two, you should sweep the roof free of all residue that has settled on the roof. This process will temporarily eliminate the spores, food and the dusty environment that captures moistures and feeds the growth and accumulation of mold and mildew.

As the roof continues to accumulate air-born contaminates, the Mildew Square again begins to develop, so frequent sweeping is important for effective preventative maintenance. How often you need to sweep off your roof will be dictated by both your seasonal and living environment such as exposure to moisture from rain, morning dew, fog and snow and airborne contaminates such as dust, sand, trees, smog and even your proximity to freeway traffic and airports that emit large amounts of pollutants.

Preventive maintenance

Rinsing the residue off the roof with water is not recommended for two reasons; moisture is one of the four elements required to establish the mildew square and the dirty water will create additional clean-up of the sidewalls and windows of your RV. Sweeping regularly is less time consuming and requires less effort than washing your roof and your RV.

It is important to note that although the dark spotting is unsightly, the growth and spread of mold and mildew does not harm the integrity of the roof. A side benefit of keeping your rubber roof clean will be the reduction, or if you are really diligent, elimination of, the dreaded black streaks!