TL;DR
Joint sand is structural, not decorative -- it locks pavers against each other so the surface behaves as one system. High pressure strips it out in seconds, and a paver field with empty joints shifts, sinks, and grows weeds. Use a wide tip at a shallow angle, keep the wand moving and well back, and plan to re-sand afterward.
Why joint sand matters more than it looks
A paver installation carries load through interlock. Each unit presses against its neighbours through the sand-filled joint, and that lateral resistance is what stops individual pavers from rocking, tilting, and migrating.
Empty joints break that. Once the sand is gone, pavers move independently, edges chip, water washes out the bedding layer, and the field starts to dip and rut.
Weeds and ants also colonize open joints quickly.
Source: interlocking concrete paver installation and maintenance guidance
The two joint materials behave differently. Regular sand washes out easily and is easy to top up. Polymeric sand contains a binder that hardens when wetted, so it resists washout better -- but when pressure does break it, the damage is patchy and repairing it means removing the failed sections properly rather than sprinkling more on top.
The settings that protect the joints
Use a wide tip. A 25 degree tip at minimum, and a 40 degree tip is better on pavers. Never a 15 or a 0, and never a turbo nozzle.
Keep the pressure moderate. Roughly 1,500 to 2,500 PSI is enough for pavers. Concrete tolerates more but the joints do not. Material tolerances are in what PSI each surface can take.
Stay back. Eight to twelve inches minimum, further if the joints look loose. Distance is the most effective control you have.
Angle the spray shallow. Point the stream across the pavers rather than straight down into the joints. A perpendicular stream lands in the gap; a shallow one skims the face.
Keep moving. A wand held still over a joint empties it in seconds.
Test a corner first. Wash a hidden area at your intended settings, let it dry, then look at the joints. If sand has moved, back off.
The full method
1. Sweep and pull weeds. Pull weeds from the joints by hand or with a joint knife rather than blasting them out. Weed killer applied a week ahead makes this easier.
2. Protect the surroundings. Soak plants and grass with plain water and keep them wet.
3. Pre-wet the pavers. This stops cleaner soaking unevenly into porous units.
4. Apply a paver-appropriate cleaner across the whole area. Pre-treating everything means stains release at the same rate as the rest, so you are not tempted to linger anywhere. Follow label dilution.
5. Dwell. Five to ten minutes, out of direct sun, never to dryness.
6. Agitate heavy areas with a stiff broom, working along the paver faces rather than into the joints.
7. Rinse with even, overlapping passes at your tested settings. Work in one consistent direction.
8. Let it dry fully before assessing the joints, usually a day or more. Re-sanding into damp joints does not work.
Re-sanding afterward
Assume you will need to top up. Even careful washing removes some sand.
Wait until everything is bone dry. Sand will not flow into a damp joint and polymeric sand will activate prematurely.
Choose the material. Regular joint sand is cheaper and easy to add to. Polymeric sand resists washout and weeds but must be installed exactly per the instructions, since a partial activation leaves a crusty haze that is hard to remove.
Spread and sweep it in. Pour sand over the surface and sweep diagonally across the joints so it falls in rather than skating along them, until they are full to just below the paver chamfer.
Compact and top up. A plate compactor settles the sand and reveals joints that need more. Without one, walking the area and re-sweeping over a couple of days does much of the same job.
Sweep the surface clean before wetting, especially with polymeric sand, since any left on the paver faces hardens there as a haze. Then wet as directed -- polymeric sand needs a specific light watering sequence, and flooding it washes it out.
Sealing, and whether to bother
Sealing pavers reduces staining, deepens colour, and helps hold the joints. It also commits you to resealing every few years and can change the appearance more than people expect.
If you seal, the surface must be completely dry -- generally several days after washing -- and the joints must be sanded first, because sealer is what locks the sand in place. Do not seal a field with efflorescence actively blooming; you will trap it under the coating.
Common paver problems
Efflorescence, a white haze of mineral salts, is common on new pavers and usually fades within a year or two. Removers exist, but they are acidic, so test first and never let them contact a bleach-based product -- acid plus bleach releases chlorine gas.
Moss and algae in shaded areas respond to a diluted bleach-based cleaner with dwell time, rinsed thoroughly, far better than to scrubbing.
Sunken or rocking pavers are a base problem, not a cleaning problem, and washing hard around a loose paver makes it worse. Weeds returning quickly usually means the joints are not full; re-sanding is the actual fix.
Brick paving has its own considerations, in how to clean a brick patio, and stacked block walls have a related joint problem in cleaning a retaining wall without loosening the blocks.
About surface cleaners on pavers
A rotating surface cleaner gives an even finish and covers ground fast, which is why it is the standard tool for flat concrete -- see a surface cleaner compared with a wand.
On pavers it is a mixed proposition. The even coverage beats a hand-swept wand, but the rotating jets still lift joint sand, so lower pressure and a committed re-sanding plan are both necessary. If the joints are polymeric and in good condition, moderate pressure is usually fine. If they are plain sand, expect to refill nearly all of them.
FAQ
How do you clean pavers without removing the sand?
Use a 40 degree tip at roughly 1,500 to 2,500 PSI, held eight to twelve inches back and angled shallow across the paver faces rather than down into the joints, keeping the wand moving. Pre-treat with a cleaner so chemistry does the work rather than pressure.
Do I have to re-sand pavers after pressure washing?
Almost always, at least partially. Even careful washing displaces some joint sand, and the joints are structural, so leaving them short lets pavers shift and weeds return. Wait until everything is completely dry, then sweep new sand in diagonally across the joints.
What is the difference between regular and polymeric joint sand?
Regular sand is loose, cheap, and easy to top up, but it washes out readily. Polymeric sand contains a binder that hardens when watered, resisting washout and weeds, but it must be installed exactly per instructions and repairs mean removing failed sections rather than adding more on top.
Can I use a surface cleaner on pavers?
Yes, at lower pressure and with a plan to re-sand. The even coverage is better than a hand-swept wand, but the rotating jets still lift joint sand. Polymeric joints in good condition handle it better than plain sand joints, which will mostly need refilling.
How do I get moss out of paver joints?
Apply a diluted bleach-based cleaner and give it several minutes of contact time, then rinse gently -- chemistry works far better than scrubbing or pressure here. Never combine that cleaner with an acidic efflorescence remover, since acid plus bleach releases chlorine gas.
This sits inside the broader whole-home work covered by house cleaning services.
Pavers reward a gentle wash and a proper re-sand far more than they reward pressure, because the joints are doing structural work. If the field has settled or the joints are widely empty, get a quote and we will look at it before anything is sprayed.