Settling: repair options

Settled pavers are repaired by lifting the affected units, correcting the bedding, and relaying them on a base that drains. A small dip is a local re-bed; a widespread hollow or a soft subgrade needs base repair at $4 to $8 per square foot. The pavers themselves usually survive, which is why settling is a repair rather than a replacement.

What settling actually is

Settling is a loss of support under the pavers. The bedding sand migrates into the base, the base consolidates unevenly, or the subgrade softens under water.

The pavers do not sink into the ground on their own. They follow the layer beneath them, which is why the pattern of the dip tells you where the water went.

A dip near a downspout, a dip in the middle of the patio, and a dip along the house wall are three different problems with three different fixes.

Repair options by scope

The deciding question is whether the base is sound. Tap the pavers with a mallet; a hollow sound over a wide area means the base has voided, and a local re-bed will not hold.

Local re-bed, step by step

1. Mark the affected pavers and lift them in the reverse order of the laying pattern.
2. Scrape the old bedding sand back to the base and inspect it for soft spots.
3. Recompact the base if it is sound, or excavate and replace it if it is not.
4. Screed fresh bedding sand to the correct height, checking the slope with a level.
5. Relay the pavers, checking each one for rock as you go.
6. Compact the field and refill the joints with polymeric sand.
7. Mist the joints and keep traffic off for 24 hours.

Lifting in reverse order and stacking the pavers in sequence makes relaying much faster. A pile of mixed pavers turns a two-hour job into a day.

Base repair on a larger area

When the settling covers a significant part of the patio, the base has to be rebuilt. That means lifting the field, removing the bedding, excavating the failed base, recompacting the subgrade, and rebuilding in lifts.

The base repair rate of $4 to $8 per square foot covers that work. On a 200 square foot patio at $6 per square foot, it is 200 × $6 = $1,200.

Add sealing at $1 to $3 per square foot: 200 × $2 = $400. The total is $1,600 for a patio that is flat, draining and protected.

What the repair costs on a real patio

A 200 square foot patio with a widespread dip is the common case.

Base repair at $6 per square foot: 200 × $6 = $1,200. Re-sanding the joints after relaying: material only, roughly $50 to $105 for two to three bags. Sealing at $2 per square foot: 200 × $2 = $400.

The total is about $1,600, and it assumes the pavers can be reused. If 10 percent of the units break during lifting, replacement adds the cost of those units.

A local re-bed of ten pavers is a few hours of labor and a bag of sand. The base repair is the option when the dip is broad or the base is hollow.

Why the water matters more than the pavers

Every settling repair is also a drainage repair. If the water that caused the dip is still flowing to the same place, the new base will fail the same way.

The usual culprits are a downspout discharging at the patio edge, a slope that runs toward the house, a low spot with no outlet, and a border that traps water against the pavers.

Correcting the outlet is often a small job: an extension on the downspout, a gravel-filled trench, or a regrade of the adjacent soil. It is cheaper than a second base repair.

When roots are involved

Tree roots lift and hollow pavers as they grow. A root that passes under a patio creates a void on one side and a rise on the other.

Grinding out a root is sometimes possible, but it can kill the tree and it leaves a void that has to be filled. In many cases the practical answer is to reroute the patio edge or accept a localized repair.

Root damage at $4 to $8 per square foot for the base work is the starting number, and it rises if the tree has to be removed.

What to check before approving a repair

Ask the contractor to identify where the water is going and what will change. A repair that does not address the water source is a repeat job.

Ask whether the base will be excavated or just re-screeded. A re-screed over a failed base is cheaper and fails sooner.

Ask how the slope will be checked, and whether the edge restraint will be inspected. Spreading edges and settling often appear together.

For the prevention side, see settling prevention. For the early signs, read settling warning signs, and for the cost detail, check the settling cost guide.