The brick walkway at one of my rentals looked like a small earthquake had run through it: pavers tipped every direction, a couple sunk an inch below their neighbors, one lifted enough that a tenant tripped and let me know about it in a strongly worded message. Pavers move for reasons that are completely predictable once you know them, and the reason yours moved decides whether you can reset them for an afternoon’s work or whether you are rebuilding the base underneath.
A paver is only as stable as its base
Here is the thing people miss about pavers and flagstone: the surface you see is not the structure. The stones just sit on a base, and everything that goes wrong is happening in the layers underneath. A proper paver installation is compacted gravel, then a bedding layer of sand, then the pavers, with edge restraint holding the whole field from spreading. When pavers move, it is almost always the base that failed, not the stones.
That is why resetting a few tipped pavers without fixing the base is a temporary fix. You are re-leveling the symptom. If the gravel washed out or the ground under it moved, the pavers will follow it right back to crooked.
The usual causes
Water is the most common. Runoff that flows across or under a walkway erodes the sand and fines out of the base, leaving voids the pavers then settle into. A downspout discharging near a path is a reliable way to wash out its base over a few seasons. Second is a base that was never compacted properly, so it consolidates unevenly under foot traffic and weather. Third, in cold regions, is frost heave lifting sections; in clay regions, expansive soil doing the same. And fourth is simple edge failure, where missing edge restraint lets the outer pavers creep outward and the field loosens from the perimeter in.
Roots belong on the list too. A tree near a walkway sends roots under it, and as they thicken they lift stones the same way they lift a sidewalk slab. Guidance on paver base and drainage from the National Concrete Masonry Association covers how the base and edge details are supposed to be built, which tells you what failed when they move.
Reset or rebuild
If the base is basically sound and a few pavers tipped or a corner settled, you can lift the affected stones, correct the bedding sand, re-level, and re-sand the joints, an afternoon and under a few hundred dollars. If the base has washed out, was never compacted, or the whole field is moving, you are into a rebuild: pull the pavers, excavate, lay and compact proper gravel base, re-bed, and reset with edge restraint. That runs more like $12 to $25 per square foot depending on access and material, but it is the version that stays flat.
The tell for which one you are facing: if the movement is localized and the rest is flat and firm, reset. If pavers rock underfoot across a wide area, or you can feel the base is soft, rebuild. And whichever you do, fix the water first, because the walkway rides on the same forces as any sidewalk trip hazard and re-settles for the same reasons.
The liability angle for a landlord
For a rental, a tipped paver is not just cosmetic, it is a trip hazard I am responsible for. The same rough half-inch threshold that flags a public sidewalk applies to the walkway a tenant uses every day. A documented hazard I knew about and did not fix is exactly the situation that turns an accident into my problem, so on rentals I treat a wobbling walkway as a scheduled repair, not a someday.
When a settled walkway needs a full base rebuild rather than a reset, a Long Island sunroom builder who does hardscape and additions can redo the base and edge restraint so it stays flat.
Frequently asked questions
Can I just add sand under the sunken pavers? As a quick reset, yes, if the base below is still sound: lift the paver, add and level bedding sand, reset. But if the gravel base itself washed out or was never compacted, sand on top is a short-term patch and the paver will settle again.
Why do only some of my pavers move? Usually because the cause is localized, a downspout washing out one area, a root under one section, or a soft spot in the base. Uniform movement across the whole field points to a base or drainage problem affecting everything.
Do I need edge restraint if I reset pavers? Yes, if it is missing. Without edge restraint the perimeter pavers creep outward and the whole field loosens over time. Adding it during a reset is what keeps the repair from unraveling from the edges.