Weeds between pavers: what actually stops them coming back
Weeds root in the joint sand between pavers, not the sub-base beneath them. Pressure cleaning blasts that sand out along with the weeds, leaving open joints that reseed within a season. The fix is re-sanding straight after the clean — plain kiln-dried sand, or polymeric if you want longer. Schmick cleans driveways and paths from $180, most $180-$420 by area.
The weeds are growing in the sand, not the ground
Pull a weed out of a paved driveway and look at the root. It stops in the joint — that narrow band of sand between the units — and almost never reaches the compacted base below. The base is dense, dry and hostile to anything green. The joint is not. Leaf litter, lawn clippings, pollen and windblown grit settle into the gaps, break down over a season or two, and turn coarse sand into something closer to potting mix. Seeds land in it. Rain waters it. Nothing else needs to happen.
That is why weeding by hand feels like bailing a boat. You remove the plant and leave the seed bed completely intact, so the next round germinates in the same fine organic layer that fed the last one. It also explains the pattern most people notice without thinking about it: weeds turn up worst along shaded edges, under the jacaranda, beside garden beds and in the low joints where water sits. Those are the joints collecting the most debris. The sun-baked middle of the driveway usually stays clear.
Pressure cleaning removes the weeds and their defence
A high-pressure jet will strip weeds and moss out of paver joints in a single pass. It also strips the sand. You can watch it go — grey ribbons washing across the paving and down the gutter — and what is left behind is an open joint, deeper than it was, holding nothing at all. The paving loses its interlock and units start to rock underfoot. Worse for this particular problem, that gap is now a clean, empty trench waiting for the next load of leaf litter to blow in.
So the driveway looks immaculate for a fortnight and then goes backwards fast. Debris fills the deeper joints, they hold more water than they used to, and the regrowth comes back thicker than it was before the clean. Homeowners read that as the cleaner having done a poor job. The cleaning was usually fine. The finishing was not. Washing a paved surface without re-sanding it is half a job, and it is the half that decides whether you are back out there with a screwdriver by Christmas.
Re-sanding is the step most people skip
Re-sanding is not glamorous and it is not optional. Once the joints are dry — genuinely dry, which in Sydney means a warm day or two after the clean, not the same afternoon — you sweep kiln-dried jointing sand across the surface and work it into every gap with a stiff broom. Then you vibrate or tamp it down, top up the joints that settle, and sweep the whole lot again. Skip the compaction and the first heavy downpour flushes most of it straight back out.
Fill the joint properly, up near the top of the chamfer, and you have taken the weed's growing medium away. There is nowhere for a seed to sit. Debris still lands on top, but it sits on a dense, packed surface and sweeps or blows off instead of settling in. That is the whole trick. Not a spray, not a magic sealer — a full joint. Most of the paved driveways that stay clean for years around the North Shore and Eastern Suburbs are simply the ones that got re-sanded.
Polymeric sand buys years and asks for more in return
Polymeric sand is plain jointing sand with a binder mixed through it. You sweep it in dry, mist it with water, and the binder sets into a firm, slightly flexible crust across the joint. Done well it resists weeds and washout for years rather than a season, which on a large driveway is worth real money in weekends alone. It also stands up to a hose and a broom in a way loose sand never quite does. That is the case for it, and it is a good one.
The catch is that polymeric is unforgiving. Joints must be dry, clean and filled to depth, the pavers swept spotless before watering — residue left on the surface can haze or stain — and the watering itself has to be judged, not a soaking. Get it wrong and you have a crumbling or blotchy joint that is a genuine chore to dig out. It also cracks where pavers shift. Plain kiln-dried sand is cheaper, more forgiving and easily topped up. Big stable sunny driveway: polymeric. Shifting or shaded paving: plain sand, more often.
What it costs, and what a clean cannot fix
Be clear about the limits. No clean and no sand stops weeds permanently. Where paving runs straight into a garden bed, or a neighbour's kikuyu is pushing under the edge restraint, runners come in from the side and no joint treatment on earth touches that. Same with a paver that has dropped and now pools water after rain. That is a laying problem, not a cleaning one. What re-sanding genuinely does is take you from weeding every few weeks to a tidy-up once or twice a year.
Whoever does the work, make re-sanding part of the brief rather than an afterthought — it is the difference between a fortnight and a year. On price, Schmick cleans driveways and paths from $180, with most landing between $180 and $420 by area, and sealing available as a set add-on. Bundle it with the windows or gutters on the same visit and you save 5 to 15 per cent. The instant quote returns a firm, bookable price in about 60 seconds, and it holds unless the place is materially different.