Joint sand is what makes interlock interlock. When it washes out the stones stop sharing load, weeds arrive, ants move in and the surface starts to shift. Refilling it properly, sometimes sold as joint renewal, is the cheapest repair this trade offers.
Polymeric sand fails in one of three ways, and none of them is age alone. It was installed damp or watered in repeatedly, so it crusted at the surface and stayed loose below. It was swept in over a joint that was never cleaned out, so it sat on old sand and broke up.
Or water runs across that part of the surface every time it rains and carries it away, which is a drainage problem wearing a joint problem's clothes. We check which before refilling, because the third one comes straight back.
Old sand, weeds and root matter come out to roughly an inch of depth, usually with a wash rather than a scrape.
Let it dry
Polymeric sand will not set into a damp joint. The surface dries fully before anything is swept in, which can mean a second visit.
Sweep and tamp
Sand is swept diagonally across the pattern and vibrated in so the joint fills from the bottom rather than bridging at the top.
Water once
A single controlled wetting activates the binder. Repeat watering is what leaves the white haze people blame on the product.
Sand Or Something Else
Refilling a joint is cheapest when it is early
The five pages here are a sequence rather than a menu. Sand washes out, the gap opens, weeds and moss take the space, and the stones stop sharing load with each other.
Caught while it is still a sand problem it is a one-day job. Left until the surface is moving it becomes a re-levelling job instead. The tell is whether the joints are merely low or empty right down to the depth of the paver, which we check with a screwdriver on the visit.
Weeds and moss are a symptom of the same gap rather than a separate problem, so they are treated in the same pass.
Five to ten years on a sheltered walkway and less on a driveway that gets washed and ploughed. Anywhere water runs across it, expect the short end.
Topping up over old sand gives you a thin crust that breaks in a season. The joint has to be cleared to depth for the new sand to lock.
It stops the ones rooting in the joint, which is most of them. Seed landing on the surface can still sprout, but it lifts out rather than holding.
For anything that gets rain or a hose, yes. Regular sand washes out in one season and takes the lock between the pavers with it.
Almost always too much water during install, which floats the binder to the surface. It fades over a season or comes off with a light acid wash.
Yes, and it should be. Anything we lift has to be re-sanded before it goes back down anyway, so doing the whole surface at the same time saves you a second mobilisation and leaves the joints matching.
