How to Pressure Wash a Patio

1. Know What Your Patio Is Made Of

Poured concrete is the most forgiving patio surface. A cured broom-finished or smooth slab handles typical homeowner gas washer pressure and a surface cleaner well, provided you keep the tool moving. Stamped and coloured concrete needs more care, because the colour is often a surface layer or a sealer that aggressive cleaning can strip.

Concrete pavers are dense and durable, but they sit on a sand bed with sand-filled joints. The pavers themselves tolerate moderate pressure; the joints do not. Pavers are also often sealed, and an older sealer can turn patchy or white when cleaned aggressively.

Natural stone varies the most. Granite and dense slate tolerate moderate pressure. Limestone, sandstone and travertine are softer and more porous, and high pressure can erode their surface, open pores and leave visible tracks. Brick sits in between, and its mortar joints can be damaged as easily as the face.

If you are not sure what you have, test on a hidden corner at low pressure and increase gradually. The right pressure is the lowest that cleans effectively. More is not better on any patio material.

2. Prep the Patio and the Surroundings

Clear everything off the patio: furniture, planters, grills, mats and toys. Furniture can be cleaned separately and should not be blasted on the patio surface. Sweep or blow off leaves, soil and grit so they do not get trapped under a surface cleaner or ground into the surface.

Protect the house. Close windows and doors, cover outdoor outlets and light fittings with plastic and tape, and keep the spray away from door seals and weep holes. A surface cleaner contains most spray, but the wand used for edges and rinsing throws water sideways and up.

Wet down nearby plants and lawn before you start if you plan to use any cleaner, and cover delicate plants. Pre-wetting dilutes runoff and reduces the chance of chemical damage. Rinse them again afterwards.

Plan where the water will go. Work from the high side of the patio toward the low side or drain, so dirty water runs over uncleaned areas rather than over finished ones. On a patio that slopes toward the house, as some do, take extra care with the final rinse to push water away from the foundation.

Check the weather. You want a dry day with a dry day following if you plan to re-sand or seal. Cleaning in direct, hot sun can make cleaners dry before they work, and cold weather slows drying for days.

3. Pre-Treat Stains and Choose a Cleaner

Pressure alone is the wrong tool for most patio grime. Algae, moss, lichen and mildew come back quickly if you only blast the surface layer, and higher pressure to chase them down is what damages softer materials. A suitable cleaner applied first does most of the work and lets you use lower pressure.

Match the cleaner to the material and the stain. A general concrete and masonry cleaner suits most organic grime on concrete and pavers. Oil and grease need a degreaser. Rust needs a rust remover formulated for masonry. On natural stone, especially limestone and travertine, avoid acidic cleaners, which can etch the surface; use products labelled safe for natural stone. Our paver cleaner rankings cover options by surface.

Apply the cleaner with a pump sprayer or through your washer's soap system, following the label for dilution and dwell time. Keep the surface wet during the dwell time so the cleaner does not dry in place. Our guide to using detergent in a pressure washer covers the soap nozzle and siphon setup.

For stubborn spots, a stiff nylon brush during the dwell time helps more than extra pressure. Avoid wire brushes on pavers and stone, which can scratch the surface and leave metal particles that rust.

4. Clean the Main Area

A surface cleaner is the best tool for the open field of a patio. It holds the nozzles at a fixed height, contains the spray and leaves an even finish, which matters on a patio people will see up close. Choose a deck size your washer can spin properly; patios often suit a 12 to 16 inch deck that is easier to steer around posts and steps. Our guide to surface cleaner sizing explains how to match it.

Move slowly and overlap each pass by about a third to a half of the deck width, working in straight lanes. Keep the deck flat. On pavers and stone, lower the pressure if your washer allows it, or use a deck with nozzles sized for lower output. Our surface cleaner technique guide covers pace, overlap and edging in detail.

If you do not have a surface cleaner, use a 25-degree or 40-degree tip, held at a consistent distance and moved in even, overlapping sweeps. Keep the wand angled slightly so the spray pushes dirt across the surface rather than straight down into the joints. Avoid 0-degree tips and turbo nozzles on pavers and soft stone; our comparison of a surface cleaner vs turbo nozzle explains why.

Clean edges, steps and corners with the wand after the field, feathering the spray into the deck-cleaned area so there is no visible boundary. Work carefully around the base of walls and along the patio's edge restraint, where joints and bedding sand are most exposed.

Our surface cleaner rankings list which attachments suit electric and lower-pressure washers, which are often the better match for paver and stone patios.

Take breaks on bigger patios. Fatigue makes people speed up and tilt the deck, which is exactly what causes uneven patches. Stopping every twenty minutes or so to move the hose and check the finished area keeps the pace consistent from the first lane to the last.

5. Protect the Paver Joints

Joint sand is what holds a paver patio together. It locks the pavers against each other, keeps weeds out and stops pavers from shifting. Pressure washing almost always removes some of it, and aggressive cleaning can strip joints to the bedding sand.

Keep pressure moderate and avoid aiming the spray straight down into joints. With a surface cleaner, keep moving so the jets never dwell over a joint line. With a wand, angle the spray across the surface rather than into it. Accept that some sand loss is normal and plan to replace it.

If the joints contain polymeric sand that is cracked, crumbling or full of weeds, cleaning is a good time to remove it and start fresh. Polymeric sand that is still intact and hard can usually be cleaned over gently and topped up where needed.

Watch the bedding sand as well. If water is blasting out from under pavers or you can see the base, you are using too much pressure for the joint condition. Stop, reduce pressure and finish more gently.

Edge restraints deserve a look while the joints are exposed. The plastic, metal or concrete edging along the patio's border is what keeps the outer pavers from creeping outward. If it has lifted, cracked or pulled away, fix it before re-sanding, or the new joint sand will open up again as the pavers spread.

6. Rinse and Let It Dry

Rinse the whole patio from the high side to the low side with a wide nozzle once cleaning is done. A surface cleaner leaves loosened dirt in a slurry; without a rinse, it dries as a haze. Rinse cleaner residue thoroughly too, since many cleaners can leave a film that affects re-sanding or sealing.

Rinse plants, lawn edges and the base of the house wall again, and wipe or rinse any spatter from windows, doors and siding.

Let the patio dry fully before judging the result or doing anything else. Wet pavers and stone look darker and more even than they are. Uneven areas or streaks show as the surface dries, and a light second pass on just those areas usually fixes them.

Drying time depends on weather and material. Porous stone and pavers can hold moisture well below the surface after looking dry. If you plan to re-sand with polymeric sand or apply a sealer, follow the product's dry time, which is commonly at least 24 hours and often longer in cool or humid weather.

Check for standing water as the patio dries. Puddles that stay long after the rest of the surface is dry point to low spots or settled pavers. Cleaning is a good moment to note them, since a paver that has sunk can be lifted, the bedding sand topped up and the paver relaid before you re-sand.

7. Re-Sand, Seal and Keep It Clean

Refill paver joints once the patio and joints are completely dry. Regular jointing sand is the simplest option; polymeric sand hardens into a firmer joint that resists washout and weeds better. Follow the product's instructions closely, especially for sweeping off residue before wetting, or it can leave a haze. Our polymeric sand rankings compare products.

Consider sealing after cleaning and re-sanding. A sealer can make future cleaning easier, slow organic growth and, with some products, help stabilise joint sand. Pavers and stone need sealers made for them, and the surface must be fully dry. Our guide to sealing pavers covers application.

Concrete patios can be sealed too. A penetrating sealer protects without changing the look much, while a film-forming sealer adds sheen or a wet look. Either way, an even clean is the starting point, because sealer locks in whatever is on the surface.

Keep it clean between washes. Sweep regularly, rinse off spills promptly and clear leaves that sit and stain. A patio that gets light maintenance needs a full pressure wash far less often, which is better for the joints and the surface.

Plan on a full clean once a year or so for most patios, or more often in shaded, damp spots where algae grows quickly. Annual cleaning at modest pressure does far less harm than a single aggressive clean every few years.