Pressure washing vs soft washing: choosing the right one

Every exterior surface has a tolerance, and the fastest way to ruin a property is to exceed it with a machine hired for the weekend.

High pressure belongs on hard, dense, well-jointed surfaces: block paving, concrete, flagged patios and tarmac in good condition. Even then it should be delivered through a rotary surface cleaner rather than a pencil jet, which is what causes the zebra striping you see on so many driveways.

Soft washing belongs on anything porous, coated or fragile. Render, K-Rend, pebbledash, painted masonry, roof tiles, slate, timber cladding and decking all fall into this group. A biocide is applied at effectively no pressure, kills the algae and lichen at the root, and the weather rinses the residue away over the following weeks.

The telltale signs of a job done with too much pressure are blown pointing, sand washed out of joints, furred timber grain, and roof tiles that lose their protective glaze and re-grow moss twice as fast afterwards.

If you are unsure which your property needs, send us a photo. Sometimes the honest answer is that a surface should be left alone for another season.