Polymeric sand is ordinary jointing sand with a binder that sets when it gets wet. That makes it very good at staying in a joint and very unforgiving about how it goes in. Almost every failure we are called to fix is a sequence problem rather than a product problem, and the sequence is the whole job.
First, sweeping it over old sand. The binder needs to bond to the paver faces, and a joint that is half full of spent material gives it nothing to grip, so the new layer breaks up within a season. Joints get opened to about an inch first. Second, installing onto a damp surface.
Any moisture already in the joint starts the binder setting before the sand is where it needs to be, and you end up with a crust on top and a hollow below. Third, over-watering.
The product sheet gives a rate and a sequence for a reason; flooding it floats the binder to the surface, which is what leaves the white haze people then blame on efflorescence. Fourth, leaving residue on the faces before watering. Whatever is on the surface when the water goes on is glued there.
None of this is difficult, it is just not optional. See how full re-sanding is staged, what joint washout tells you about water, and when paver sealing should follow.
Polymeric Sand
How It Runs
Four steps to a joint that actually holds
Open the joints to depth
Spent sand comes out to roughly an inch with a blade or a blower, because new sand over old sand has nothing to bond to.
Wait for a dry surface
Both the pavers and the joints have to be dry through, so this work waits on the weather rather than on the schedule.
Sweep and vibrate in
Sand is worked in and tamped so the joint fills from the bottom up rather than bridging at the top over a hollow.
Clear the faces, then water once
Every grain is blown off the paver faces before water goes on, then it is watered to the product rate in one pass.
Product Choice
Not every joint wants the same sand
Joint width, paver type and how much water crosses the surface all change what should go in. Wide joints and flagstone need a product rated for the gap, and a driveway that is plowed and washed wants a harder-wearing grade than a sheltered patio.
Price runs roughly twenty to ninety dollars a bag across that range, and using the cheap one in the wrong place is a false economy. See what flagstone repair needs in its joints, how joint re-sanding is sequenced, and why weed removal without it is temporary.
$20 to $90Bag price
Joint width and useChosen by
A harder gradeDriveways
Related Work
Other joint repair work in Toronto
What usually goes in at the same time as new sand.
No. The binder needs to bond to the paver faces, and a joint half full of spent sand gives it nothing to grip. The joints get opened to about an inch first.
Five to ten years on a sheltered walkway and less on a driveway that gets washed and plowed. Sooner than that usually means it went in wrong rather than wore out.
Almost always over-watering, which floats the binder to the surface, or residue left on the paver faces when the water went on and then glued there.
It stops weeds rooting in the joint, which is where most of them start. Seed landing on top of a filled joint can still germinate in surface debris.
Early fall yes. Late fall rarely, because the surface needs to be dry through and stay above about ten degrees while the binder sets.
Once it has cured properly, rain is what it is built for. The risk window is the first few hours, which is why we watch the forecast and move a date rather than start into weather. A shower on a half cured joint is how the white haze happens.
