Pressure washing shouldn't damage a patio or driveway if the pressure and technique are matched to the surface — but using too high a pressure, the wrong nozzle, or holding the jet too close can damage joints, pointing and softer materials.
The main risk isn't the water pressure itself but how it's applied. Block paving has sand-filled joints between the blocks that can be blasted out by an aggressive, close-up jet, leaving the paving looser and more prone to shifting. Natural stone and older or softer paving can be etched or have its surface damaged by excessive pressure. Mortar joints in an older patio can also be eroded by a jet held too close for too long.
Used correctly — the right pressure, the right nozzle, kept moving rather than held in one spot, and with joint sand re-applied afterwards where needed — pressure washing is a safe and effective way to remove moss, algae, grime and staining without damaging the surface underneath.
If a patio or driveway is already cracked, sunken, or has loose slabs rather than just being dirty, pressure washing won't fix that — that's a repair job, not a cleaning one, and pushing a jet washer over damaged paving can make loose sections worse rather than better. Lancashire's damp climate means algae and moss build up on patios and driveways faster here than in drier parts of the country, which is why pressure washing is such a regularly requested job across Preston and the surrounding area.
GreenFix provides pressure washing across Preston and Lancashire. From £95 (per visit, guide price only).
