Big flat surfaces, and one very specific vulnerability.
Seams and seals
Never point a jet at a seam, a window surround, a rooflight, a vent, an awning rail or a light cluster. All of them are watertight by sealant, not by design, and sealant fails from the edge.
Wide fan, well back
A meter or more, wide setting, moving. On the panels this is fast and safe.
Use a brush head for the streaks
A rotating wash brush with a caravan shampoo does what pressure cannot: it works the bonded deposit off mechanically at a pressure that cannot get behind anything.
The roof is the dangerous part
Not because of the cleaning, but because you should not be standing on it and because it is where every seam lives. Use a telescopic brush from a platform, and get a leak checked professionally rather than washing the evidence away.
Rinse everything, then look for water inside
After the first wash of the season, check the lockers and the corners for damp. Finding a failed seal in the driveway in April is a very different problem from finding it in a field in August.
The questions we hear
Can I use a pressure washer on a caravan at all?
At a wide fan setting, from a meter or more, never aimed at a seam or a rooflight — yes, and it saves a great deal of time on the panels. The damage cases are all the same: a narrow jet held close to a seal, and a leak that appears months later.
What removes black streaks?
A dedicated caravan streak remover with dwell time, applied bottom up, then a soft brush. Pressure does not shift them because they are a bonded deposit from the roof rails, not loose dirt — which is why people escalate the pressure and damage the seals.
Last reviewed 2026-08-16
