Ask Dave: What should I use to clean and protect RV’s fiberglass roof?

Dear Dave,
What do you recommend to clean and protect my RV’s fiberglass roof? I have used Dawn dishwashing liquid and warm water with a soft brush to clean the tent material, but the top seems like it needs something stronger and maybe a stiff brush. Any suggestions would be appreciated. Thanks. —John Bilbrey, 2021 Forest River Flagstaff 206STSE pop-up camper

Dear John,
Your Flagstaff ST Sports Enthusiast camper has what is called a pebble grain fiberglass panel, which is typically a Crane Composites product. The pebble grain term comes from the bumpy surface. It is actually additional resin drops that help add strength to the fiberglass. Several RV manufacturers use it, especially when the roof material curves or wraps around the roof to a sidewall joint that is prone to cracking. You can see by the photo I got off the FR site that the material wraps around the front and back.

Cleaning your RV’s fiberglass roof

Crane Composites recommends washing with a mild detergent. I am a big fan of Dawn Dish Soap (blue), as it is environmentally friendly and does a good job on tree sap and bird poo. Remember, it was used to clean oil off birds and wildlife in Alaska! Also, use a mild brush.

They discourage using caustic cleaners with abrasives and anything with high alkaline or pH. The outer layer of material on your roof is a thin gelcoat or clear finish, even though it doesn’t have much of a shine. Some sidewall material has several layers to give an automotive finish or higher shine. Using heavy abrasives or stiffer brushes can wear off the gelcoat and expose the fiberglass to UV degradation.

If you wash the roof and still has stains, they recommend using a tar or insect removing product. If you do this, test it on a small area first to make sure it does not discolor the surface. For severe stains, they recommend buffing with Mirka Polarshine 35. Keep in mind that is going to buff off some of the gelcoat, so they recommend following up with Mirka Polarshine 8/10 polishing compound.

Protecting your RV’s fiberglass roof

The best thing you can do is clean it thoroughly and wax the surface with Meguiar’s #56 Boat and RV Pure Wax, as this has UV protection built in. Wash it every six months or more, depending on how often it is exposed to dirt and tree sap. With a good wax, these items will wash off easily and you will not need to get aggressive with other products.

Also, keep the unit covered when in storage, as constant exposure to the sun and other elements will deteriorate even the best wax and fiberglass.

Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.

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