How to Remove Black Streaks From an RV

Those black streaks running down the sides of your RV come from dirt and oxidation washing off the roof, awning rails, and seals every time it rains. In wet coastal BC they appear fast. The good news: they come off — if you treat them right and don't scrub the finish away.

What causes the streaks

Rain carries dirt, mildew, and oxidized residue off the roof membrane, the metal awning rails, and the rubber seals, and it runs down the sidewalls. The streaks tend to start under the roof edge, awning, and window frames — anywhere water sheets off. The longer they sit, the more they stain the fiberglass and gelcoat.

Wash first, treat second

Start with a proper hot-water wash from the top down to clear loose dirt. Trying to treat streaks over a dirty surface just grinds grit into the finish. Once it's clean, you can see the actual staining you're dealing with.

Use a dedicated streak remover, not a scouring pad

Purpose-made RV black-streak removers dissolve the stain so it lifts off with light agitation. Abrasive pads and harsh scrubbing strip the gelcoat and dull the finish — which causes the oxidation that makes future streaks worse. Apply, let it dwell, then wipe and rinse.

Protect to slow them down

After the streaks are off, a wax or sealant on the sidewalls helps water sheet off instead of staining, slowing how fast the streaks return. Treating the roof and resealing as needed also reduces what washes down in the first place.