How to Keep Sand Between Pavers

1. First, Work Out Where the Sand Is Going

Paver joints lose sand for six main reasons, and the pattern of loss usually tells you which one is at work. Before you buy anything, walk the patio or driveway and look at where the joints are low, not just that they are low. Uniform loss everywhere is a different problem from loss along one edge, in one channel, or around little piles of fine grains.

The order of fixes below runs from cheapest and simplest to most involved. Most people only need the first two or three. The point of diagnosing first is to avoid spending a weekend installing polymeric sand on a patio whose real problem is a downspout, because no joint material survives concentrated water running across it every storm.

One distinction is worth making early. This guide is about joints that will not stay full, whatever is in them. If you already have polymeric sand and it is crumbling or washing away, that is usually a curing failure, and our guide on why polymeric sand washes out walks through that diagnosis specifically. Come back here if it turns out the problem is drainage, edges or the base.

2. Fix One: Top Up the Right Sand and Compact It

New joint sand always settles. Rain and foot traffic vibrate the grains down into voids that sweeping alone never reached, so a patio that looked full on installation day often has joints a quarter of an inch low a few weeks later. That is normal, and it is the one form of sand loss that topping up genuinely solves. Many installers check again after the first few weeks and after the first winter, and refill both times.

Use angular sand, not play sand

The grain shape matters more than most people expect. Angular, sharp sand locks against itself and against the paver edges; rounded sand rolls like ball bearings and washes out more easily. Washed concrete sand or a bagged paver joint sand are the usual choices. Fine, rounded play sand is the classic wrong one, and our comparison of paver sand vs play sand explains why it disappears so quickly. If you have been offered silica sand, our guide to silica sand for pavers covers what it is and where it does and does not fit.

Fill, vibrate, fill again

Do it on a dry day with dry sand and dry pavers, because damp sand clumps and bridges the top of the joint instead of running down into it. Spread sand over the surface, sweep it diagonally across the joints, then vibrate it in. On a driveway or large patio that means a plate compactor fitted with a protective pad so it does not chip the pavers. On a small patio, tapping along the joints with a rubber mallet over a board does a slower version of the same job.

Vibration is the step that makes the difference. Sweeping fills the top of the joint; vibration settles the sand to the bottom and exposes how much more the joint will take. Sweep more in, vibrate again, and repeat until the joints stay full after a pass. Then sweep the surface clean. A joint that has been vibrated full holds far longer than one that was only swept, simply because there are no voids left for rain to collapse.

If you are not sure how much to buy, our paver sand calculator estimates bags from area, paver size and joint width. Buy one more bag than it suggests; refilling a patio that has been neglected for a few years can take noticeably more than a fresh installation.

3. Fix Two: Stop Removing the Sand Yourself

A surprising share of sand washing out between pavers is not washing out at all. It is being cleaned out. Three household habits do most of the damage, and changing them costs nothing.

Pressure washing

A pressure washer pointed down a joint will empty it in seconds, and many people pressure wash every spring and then wonder why the joints are always low. If you must use one, use a wide fan tip, keep the wand moving, and angle the spray across the joints rather than into them. Better still, clean with a paver cleaner, a stiff broom and a garden hose; our roundup of the best paver cleaners covers products that do most of the work chemically. Whatever method you use, plan to re-sand afterwards.

Sweeping and blowing

A stiff broom swept along the joints, rather than across them, drags sand out with every stroke. So does a leaf blower held at a steep angle close to the surface. Sweep across joints with a soft broom, and hold the blower nozzle higher and flatter so it moves leaves without scouring the joints. These sound trivial, but on a patio that is swept or blown weekly they add up to a lot of sand over a season.

Ants

Ants love paver joints: the sand is easy to dig, the pavers hold warmth, and the joint gives shelter. They excavate fine grains and pile them on the surface, emptying the joint from below. Spraying surface insecticide into the joints tends to move the colony rather than end it. Slow-acting baits, which workers carry back to the nest, are the approach most pest-control guidance favours. Once the activity stops, refill the joints. A bound joint material such as polymeric sand is much harder for ants to dig through, which is one of the better reasons to switch.

4. Fix Three: Switch to Polymeric Sand

If the joints are low because of ordinary weather rather than one obvious culprit, and you are tired of topping up regular sand every season, polymeric sand is the usual next step. It is graded sand blended with a polymer binder that activates with water and cures into a firm but flexible joint. Properly installed, it resists rain, discourages weeds and ants, and stays put far better than loose sand. Our comparison of polymeric sand vs regular sand sets out when the upgrade is worth the extra cost.

The catch is installation. Polymeric sand is unforgiving in a way loose sand is not. It needs joints of adequate depth, completely dry pavers and joints, a dry forecast for at least a day, temperatures within the label range, and careful watering that saturates the full joint without flooding binder onto the surface. Most failures trace back to one of those. Our guide on how to use polymeric sand covers the method step by step.

You cannot just sweep it over the old sand

This is the mistake that turns a fix into a new problem. Sweeping polymeric sand into joints that are still mostly full of old sand gives you a thin cured crust over loose material. It looks finished, then cracks and lifts in the first hard winter or heavy storm. The old sand has to come out to the depth the product specifies, typically an inch or more. Our guide on whether you can apply polymeric sand over existing sand explains how much to remove and the tools that make it bearable.

Re-applying polymeric sand on an older patio

Polymeric joints do erode slowly over years, mostly at edges, in drainage paths and where shovels and plough blades pass. Re-applying polymeric sand to those spots is normal maintenance, but the same rule applies: clear out the loose, eroded material first and refill into sound, dry joints. Topping up a cured joint with a thin skim of new polymeric sand rarely bonds well. Choosing a product rated for your joint width matters too, and our tested picks for the best polymeric sand list the joint-width range each one is rated for.

5. Fix Four: A Joint-Stabilising Sealer

There is a middle path between loose sand and polymeric sand: refill the joints with ordinary joint sand, then apply a paver sealer formulated to soak into the joints and bind the top of the sand. These are sold as joint-stabilising or sand-binding sealers. SEK Surebond's SB-1300, for example, is marketed as a single product that seals the pavers and stabilises the joint sand at the same time.

Sealer makers position this approach for particular situations. Trident, which sells both joint-stabilising sealers and polymeric sand, says in its own technical bulletin that joint sand plus a stabilising sealer suits areas that stay damp, such as shady patios, areas under decks or spots with heavy drainage, because polymeric sand needs to dry completely to cure. The same bulletin recommends polymeric sand with a sealer for heavier loads and vehicle traffic, such as some driveways. That split is a reasonable starting point.

The advantages are speed and forgiveness. Regular sand is easier to install than polymeric sand, there is no haze risk from over-watering a binder, and the sealer protects the paver surface from stains at the same time. The disadvantage is that the binding is tied to the sealer. As the sealer wears, the joint binding weakens with it, so the joints are only as stable as your resealing schedule. Our guide on how to seal pavers covers the application, and the full sequence matters: refill and vibrate the joints, let everything dry, then seal.

If you already have polymeric sand and want to seal over it, the order and waiting time are different, and our guide on whether to seal pavers before or after polymeric sand covers that sequence. Do not apply a joint-stabilising sealer over joints that are low; it binds whatever is there, and a bound half-empty joint is still half empty.

6. Fix Five: Edge Restraint

If the joints nearest the perimeter keep opening up, the sand is probably not washing out. It is being pulled apart. Pavers without solid edge restraint creep outward under traffic and freeze-thaw, a fraction at a time. As they spread, the joints widen, the sand drops into the new gap, and the outer pavers start to rock. Refilling those joints is pointless until the spreading stops.

Edge restraint can be a concrete curb, a mortared soldier course, or more commonly on residential work, plastic or aluminium edging spiked into the compacted base. Edging makers give specific spike guidance. Western Interlock's installation guide recommends 10-inch spikes at roughly one-foot intervals for pedestrian areas and a spike about every eight inches for vehicle traffic, and Unilock describes typical spacing of eight to twelve inches, tighter for driveways. The edging has to sit on the compacted base, not on loose soil, or it will move with the pavers.

On a patio that has already spread, you may need to lift the outer row or two, push the field back, re-screed the bedding where needed, relay the edge pavers tight, and then install the restraint before refilling every joint. It is a day's work on a typical patio, but it is the only fix that lasts. Edging that is merely tacked on beside already-spread pavers stops further spreading but leaves wide joints that will keep losing sand.

Check the restraint every spring along with the joints. Plastic edging spikes can heave in frost, and a single lifted section is enough to let the edge row start creeping again. Hammering a lifted spike back down takes a minute; dealing with a spread edge a few years later takes a weekend.

7. Fix Six: Drainage and a Settling Base

Water running across the joints

Paver surfaces are designed to shed rainfall across their width. They are not designed to carry a downspout's worth of water along one line every storm. When the sand keeps disappearing from the same run of joints, find where that water is coming from. Common culprits are downspouts discharging onto the pavers, roof runoff dripping from an eave without gutters, lawn or beds shedding water onto one corner, and a patio that slopes toward the house rather than away from it.

The fix is to move the water, not to strengthen the joint. Extend or bury downspouts, add a gutter, regrade the soil beside the patio, or install a channel drain where water has to cross. Then refill the affected joints. Even polymeric sand eventually erodes under concentrated flow, and the washout guide linked above covers how to confirm a drainage cause by watching the patio in real rain.

When the base is the problem

If sand keeps dropping into the same dips, and the dips keep getting deeper, the bedding or base beneath the pavers is settling. This happens with an under-compacted or too-thin base, with soft subsoil, or where water has been getting under the pavers for years and washing fine material out of the bedding layer. Sand in the joints is the visible part of the system, but it cannot hold up pavers that are sinking.

The repair is to lift the pavers in the affected area, dig out and replace or recompact the base, re-screed fresh bedding sand to the correct level, relay the pavers, and refill and vibrate the joints. It is more work than any other fix here, but a localised repair on a few square yards is a manageable weekend job. Topping up the joints over a sinking base just fills a slowly deepening hole with sand.

Once the base, drainage and edges are sound, the earlier fixes work as intended. A well-built patio with angular joint sand vibrated full, cleaned gently and inspected each spring can keep its joints filled with only occasional top-ups. Upgrading to polymeric sand or a stabilising sealer simply extends the interval between them.