Cleaning Block Paving With a Pressure Washer: The Right Way to Do It

Block paving cleans up beautifully with a pressure washer, but only if you keep the lance moving and hold the right distance. The short version: use a 25 degree fan tip roughly 20 to 30cm from the blocks, work in overlapping passes across the paving rather than along the joints, and expect to re-sand afterwards. Everything below is about doing that without leaving stripes, scars or loose blocks behind.

Get the drive ready first

Sweep the whole area properly before any water touches it. Loose grit turns into airborne shot the moment you pull the trigger, and it will chip render, pit paintwork and scratch glass. Anything you can remove dry is dirt you do not have to chase around in a slurry later.

Then deal with weeds and moss. Pulling weeds by hand or with a block paving knife is worth the twenty minutes, because a jet strong enough to blast a rooted weed out of a joint is also strong enough to strip the joint. Moss lifts easily under water, though killing it off a day or two beforehand means far less work.

• Move cars, bins and anything else you do not want speckled in muddy water
• Cover or close nearby air bricks, vents and cat flaps
• Check where the runoff will go, and keep it away from planting beds if you have used a chemical cleaner
• Tape a plastic bag over any exterior sockets at low level

Nozzle choice matters more than machine size

Most damage to block paving comes from the tip, not the pump. A red zero degree pencil jet concentrates everything into a point and will carve a visible line into a concrete block in under a second. Keep it out of your hand for this job entirely.

The green 25 degree nozzle is the sensible default for block paving. It spreads the energy over a workable width, lifts embedded dirt, and is forgiving if you drift too close. Yellow 15 degree tips have a place on stubborn oil stains or heavily blackened areas, but treat them as a spot tool and go back to the wider fan for general work.

Better still, use a rotary patio cleaner attachment if you have one. The enclosed head holds the jets at a fixed height and spins them, so no single spot takes sustained pressure and the finish comes out far more even than a hand held lance manages.

Working across the paving

Start at the highest point and work downhill so dirty water always runs onto uncleaned areas rather than back over finished ones. Hold the lance at a shallow angle, around 30 to 45 degrees to the surface, so the jet pushes debris ahead of it instead of driving straight down into the joints.

Sweep in steady, overlapping strokes and never let the lance pause. A stationary jet is what creates those pale scoured patches people notice once everything dries. Overlap each pass by about a third so you do not leave the faint tiger stripes that appear when the edges of the fan clean less than the middle.

Direction is worth thinking about too. Move across the run of the joints rather than tracking along them. Following a joint line means the jet sits over the same sand channel for the entire length of the driveway and empties it completely.

Stubborn stains

Oil and tyre marks rarely come off with water alone, however long you attack them. A degreaser left to dwell for ten minutes does more than another five minutes of blasting, and it does it without eroding the block. The same goes for black lichen spots sitting flush with the paving: they need chemistry and patience, not more pressure.

Replacing the jointing sand

Assume you will lose sand. Even a careful job with a rotary head pulls some out, and joints left empty allow blocks to shift, rock underfoot and let weed seed straight back in. This is the step people skip, and it is why a driveway cleaned last spring often looks worse a year later than one that was never washed at all.

Wait until the paving is properly dry, usually a day or two of decent weather. Tip kiln dried sand over the surface and brush it into the joints with a stiff broom, working diagonally across the blocks in several passes. Top up as it settles, because joints that look full often drop once you walk on them or the first rain arrives. Polymeric jointing sand resists washout better if you want a longer lasting result.

How often is sensible

Once a year suits most UK driveways, ideally in late spring once the winter algae has grown but before it bakes on over summer. Washing more often does not keep the paving cleaner for long, and each session costs you jointing sand and a little of the block surface. A regular sweep and an occasional dose of moss killer will hold things between proper cleans.