How to Clean Concrete Pavers and Keep the Joint Sand
Pavers can take pressure, but the sand between them cannot take much. What the concrete paver industry's own cleaning guide says about pressure, nozzles, efflorescence and sealing.
The short answer
Concrete pavers can be cleaned with real pressure, but the joint sand between them is the weak point. The industry guide puts professional cleaning at 1,000 to 4,000 psi with a wide spray at a low angle, which cleans the face without blasting the sand out. White efflorescence needs its own cleaner at very low pressure.
Why pavers are different from a poured driveway
A poured concrete driveway is one slab. A paver patio or drive is hundreds of separate units sitting on a sand and gravel base, with sand packed into the joints to lock them together. The pavers themselves are tough. The sand is not, and losing it is how pavers start to shift.
What the industry guide says
The Concrete Masonry and Hardscapes Association publishes a technical guide on cleaning and sealing interlocking concrete pavers (CMHA PAV-TEC-005-22, revised 2022):
- Pressure and flow: professional cleaning uses 1,000 to 4,000 psi, at 2 to 6 gallons a minute.
- Nozzle and angle: a wide spray covers more area, and a low angle from a wide nozzle reduces the risk of knocking out joint sand.
- Rinsing: a large amount of water matters more than high pressure.
- Efflorescence (a white, powdery deposit on the surface): its cleaner goes on at only 30 to 100 psi, is scrubbed in, then rinsed. Judge the result after the area has dried for at least 24 hours.
- Plants: tie back or cover nearby shrubs, and let cleaning solutions drain across the pavement, not onto grass or beds.
- Before sealing: all dirt, oil and efflorescence must be removed, and the surface must be completely dry for most sealers.
How we clean pavers
Flatwork is the one place we use high pressure: cold water at high pressure on concrete, asphalt and paver drives, with a degreaser added where cars park and drip oil. On pavers the angle and spray width matter as much as the pressure, which is why the industry guide spells them out.
Oil, tire marks and dark growth
Pavers get the same oil spots, tire marks and shaded growth as poured concrete. Those are covered in oil stains and tire marks and growth on concrete patios.
What cleaning will not fix
Cleaning will not level sunken or rocking pavers, fix broken ones, or stop weeds that grow from the base below. Washing can move some joint sand even when it is done carefully, and refilling the joints is a separate step. Pavers must be completely dry before most sealers go on.
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