How to clean pavers and pool decks

Yes. The Concrete Masonry and Hardscapes Association maintenance guide for interlocking pavers lists the pressure washer as the common cleaning tool. The catch is the joints: washing pulls the sand out from between the pavers, and it has to go back in afterward.

Treat first, then wash with control:

• Treat mildew, algae and stains first with a cleaner made for concrete pavers, so the water has less to do.
• Keep the wand moving at a steady distance and a low angle. Never hold a narrow tip close to one spot.
• Rinse toward the lawn or a drain, not into the pool.
• Let it dry, then refill the joints with sand.

Almost always. Pressure washing pulls joint sand out, and empty joints let pavers shift and weeds grow. The CMHA guide says joints that have dropped more than half an inch need refilling, with dry sand swept back and forth across the surface until it falls into the joints. It also advises against polymeric sand for topping up joints.

Efflorescence, a white powdery haze from salts in the concrete working their way to the surface. The CMHA guide calls it cosmetic, not structural, and says it comes off with cleaners made for concrete pavers.

One made for concrete pavers and for the stain you have. Mildew and algae respond to bleach based cleaners diluted by the label, with plants wetted down first and rinsed after. Oil needs a degreaser, and fast: the CMHA guide notes oil sinks deeper the longer it sits. Skip straight muriatic acid on pavers, because it can etch the surface and change the color. Orange stains from sprinklers are iron and need a rust remover; see how to remove irrigation rust stains.

About once a year for most decks, and more often for shaded decks, decks hit by sprinklers and anything right next to a pool that splashes. Do not wait for the calendar if it is getting slick: green and black growth on a pool deck is a slipping hazard.

It is optional. The CMHA guide says sealers help pavers resist water and stains, and that pavers should be cleaned before any sealer goes on. Sealed pavers are easier to keep clean but need sealing again over time.

Yes. Patios, pool decks, sidewalks and driveways are all part of our pressure cleaning, around Wellington and the towns nearby. Driveways have their own guide: how often to pressure wash a driveway.