Monday, December 4, 2023


Is runoff from fiberglass roof staining sides of RV?

By Chris Dougherty
Certified RV technician

Dear Chris,
I am getting white streaks on the side of my Newmar Ventana RV from the water from the roof AC units. They are next to impossible to remove with anything that will not harm the finish. Newmar and others say the fiberglass roof oxidizes in the sun and the AC water picks up the resulting particulates, and that’s the cause. Hard for me and Wade Maid folks to believe my new coach roof would be doing that so soon (I took delivery July 2014). Another tech thinks minerals are from the metal in the AC Unit. Ideas? —Ed

Dear Ed,
Streaks from the roof are a common occurrence with RVs, and there are a few fixes that can help. First, the air conditioner is not the cause, and no metals are coming from it. I’m more in line with the roof oxidation theory, or a lot of dirt and environmental fallout causing the stubborn stains.

Wax is your best friend in this regard. A well waxed fiberglass or aluminum surface is much easier to clean, and is protected from soils settling into the surface, being difficult to remove. I think if you wash and then wax the fiberglass roof, and then the sides, any soils that find their way down will be much easier to remove.

I would advise using the highest quality wax for fiberglass you can find for the roof. There are a number of good ones, especially in the marine industry that might provide a longer lasting, more durable finish.

Although I am not familiar with Wade Maid, I agree that extreme oxidation with such a young unit is unusual, but by no means impossible. In fact, I really don’t see it happening the way you describe without exposure to a caustic substance.

If the roof finish is becoming rough or badly faded already, I would discuss the situation with the manufacturer and/or your selling dealer to get a visual inspection to make sure there is no physical problem with the fiberglass sheets used for the roof. I would do this sooner than later, so it is documented during the warranty period.



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