How to Clean a Fiberglass RV

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Fiberglass RVs have a protective barrier of hard resin polyurethane coating, known as gel coat, that protects the surface of your RV and provides the glossy appearance fiberglass is known for. Dirt and debris, sap and bugs, oxidation from acid rain and UV exposure can make your RV appear dull and dingy. A good cleaning before your next trip will restore the shine and seal the finish of your fiberglass motor home, tag-along or fifth wheel.

Items you will need

  • Rubber gloves

  • Cotton cloth

  • Fiberglass wax

  • Ladder

  • Broom

  • Bug and tar remover

  • Sponge

  • Liquid laundry detergent

  • Methyl ethyl ketone (MEK)

Step 1

Sweep the RV roof with a broom. Be careful not to sweep any dirt or leaves into the drain under any roof-mounted air conditioning equipment. Use a ladder to reach all areas of the roof and avoid damaging the roof's protective surface.

Step 2

Apply a bug and tar remover formulated for fiberglass to any of the areas affected by bugs, tree sap or white or black streaks caused by roof oxidation. Bug and tar removers safe for fiberglass can be purchased at any auto parts store or an RV supply warehouse.

Step 3

Wash the fiberglass with a sponge that has been dipped in a solution of 1 cup of liquid laundry detergent and 1 gallon of warm water. Start at the roof line. Re-wet the sponge often to avoid dirt transfer.

Step 4

Rinse the detergent off by spraying the RV with a garden hose. Allow the surface to dry naturally.

Step 5

Put on gloves. Dampen a cloth with MEK and wipe down the fiberglass with it. Start at the top and working down the sides. Reapply the MEK to your cloth as needed so that the solvent removes grease and oils. Methyl ethyl ketone (MEK) can be purchased at a large home improvement store, RV supply store or any paint store that carries solvents.

Step 6

Apply a fiberglass wax by following the manufacturer's instructions. The wax will fill any microscopic pitting in the gel coat and restore the reflective surface.


  • Always wear gloves when using MEK. It is a caustic solvent that can cause severe skin irritation.


  • Waxing at least once a year will keep the gel coat surface strong and prolong the life of the fiberglass.
  • If you RV needs restoring, use a fiberglass polish to remove a layer of the fiberglass and apply a rubbing compound with an electric buffer after completing the washing process.
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