Guide · DY Exterior Cleaning Ltd
Pressure washing vs soft washing: which one does your job need?
Pressure washing uses water force to lift dirt, right for hard surfaces like driveways, patios and walls. Soft washing uses biocide at very low pressure, essential for roofs, render, painted walls and anything with a finish coating. Using the wrong method causes permanent damage.
Pressure washing, for hard, durable surfaces
High water flow + controlled pressure. Ideal for block paving, concrete, tarmac driveways, sandstone patios, brickwork and commercial yards. Done with a flat rotary head (not a narrow lance) it lifts ground-in dirt without etching.
Soft washing, for sensitive surfaces with coatings
Low pressure + biocide chemistry. Essential for roof tiles, K-Rend and monocouche render, painted walls, soffits, cladding and timber. Kills algae and moss at the root rather than physically blasting it off.
What goes wrong when you use the wrong method
Pressure washing a roof: strips tile coating, forces water under laps, voids warranties. Pressure washing render: scours and opens the surface, leads to long-term water damage. Soft-washing a driveway: doesn't have the mechanical force to lift ground-in dirt.
How to know which one you need
Rule of thumb: if the surface has a finish coating (paint, render, tile coating, K-Rend) it needs soft wash. If it's bare hard surface (paving, brick, concrete, tarmac) it can take pressure. When in doubt, ask for soft wash, you can step up to pressure but you can't undo damage.