A paver patio or walkway sinks in patches, and the pattern of the dip tells you why. A low spot under a downspout means water has been washing the fine material out from below. A dip in the middle of a field of pavers usually means the original base was thin or never compacted. Small craters along the joints often turn out to be ant colonies hauling bedding sand out one grain at a time. Tree roots are the one cause that pushes pavers up instead of letting them drop.
Whatever the cause, the fix is the same: you have to rebuild what's under the pavers, because that's the part that failed.
Mark an area bigger than the dip. The visible low spot is smaller than the failed base under it. Plan to lift pavers at least a foot past the dip in every direction, out to where the surface is solid and level again. Snap a photo of the pattern before you start so it goes back together the same way.
Lift the pavers out. The first paver is the fight. Work a pry bar or paver puller into a joint and ease it up evenly so you don't chip the edges. Once one is out, the rest lift by hand. Stack them in order on the grass, dirty side down.
Dig out the failed bedding. Scrape out the old sand down to the gravel base and check what you're standing on. Soft, spongy spots or base that's only an inch thick are the real problem — dig those areas out until you reach firm ground. If you find an ant nest, clear it out completely; they'll be back if you leave them a home.
Rebuild the base and compact it in lifts. Add crushed gravel base a couple of inches at a time and pound each layer flat with the hand tamper. As a rule of thumb, a sound base runs about 4 inches deep under a walkway and closer to 6 under a driveway, where the loads are heavier. This step decides whether the repair lasts two years or twenty. The finished base should sit firm, flat, and roughly an inch plus a paver's thickness below your finished height.
Screed a fresh bedding layer. Lay two rails or a straight board across the base and spread coarse sand about an inch thick, pulling the board across to level it. Don't walk on the screeded sand afterward — work from the finished edge and lean.
Relay the pavers. Set each paver straight down into place rather than sliding it, which drags sand into ridges. Tap it home with the mallet and check constantly with the level and by sighting across the surface. Pavers should finish a hair above the surrounding surface — they'll settle a fraction as the joints fill.
Fix the edge restraint. Patios spread when the border restraint fails, and spreading joints let bedding sand escape. If the plastic or metal edging on the repair side has pulled away, reset it and drive fresh spikes before you fill the joints.
Fill the joints with polymeric sand. Sweep it across the surface until every joint is full, then tap the pavers or run a tamper over carpet scraps to settle it in and top up low joints. Blow or brush every trace of dust off the paver faces, then mist lightly with the hose exactly as the bag directs. Polymeric sand hardens in the joints, which keeps it from washing out and discourages ants and weeds. For the joints you're not relaying — a driveway where the pavers are sound but the weeds are winning — kill first, then top up the sand: here's how to kill weeds in driveway cracks so they don't simply grow back through the fresh fill.
Sprinkling sand on top. The most common non-repair. Sand over the top raises nothing underneath, washes into the joints in one rain, and the dip is back by the next storm — because the hole below never got filled.
Using play sand or fine sand as bedding. Fine, round grains shift and wash. Coarse, angular concrete sand locks together and stays put, which is the whole point of a bedding layer.
Skipping compaction. Loose gravel feels solid underfoot for a week. Compacted in thin lifts, it's solid for years. This is the step everyone wants to rush and the one that matters most.
Working on a soaked base. After heavy rain the base can be soup. Let it dry out first or you'll be compacting mud, and mud pumps and shifts no matter how hard you tamp.
For a typical low spot, this is a one-afternoon job with bagged materials and no special skills — just patience in the tamping. And if your pavers sit near a patio door or walkway you use daily, a level surface isn't cosmetic; a settled edge is a trip hazard waiting for a dark evening. While you're in yard-project mode, keeping the patio clean is easier with the right tools — our pressure washer buying checklist covers what to look for, and if the repair grows into a full rebuild with a base or walls, check local rules first the way you would for building a shed without a permit.
Almost always water. A downspout, a slope, or a leaking joint is washing fines out of the base a little at a time. Rebuilding the base fixes the dip; redirecting the water fixes the cause. Ant colonies are the second most common repeat offender.
No. The paver is low because material underneath it is gone. Sand on top doesn't replace that material, and it disappears into the joints within a rain or two. There's no shortcut around lifting the pavers and rebuilding the base.
Coarse washed concrete sand under the pavers as the bedding layer — its angular grains lock together. Between the pavers, polymeric sand, which hardens after a light misting and resists washout, weeds, and ants far better than plain sand.
For a small patch, materials are modest: a few bags of paver base and concrete sand plus a bag of polymeric sand often come in under $50 total. Larger areas scale with how much base you have to replace.
A single low spot of a dozen or so pavers usually takes two to four hours, most of it in digging out and compacting the base. Polymeric sand then needs its curing time — keep traffic off it as long as the bag specifies, often a day.