Why do paver patios sink?
Pavers sink when the base under them is too shallow, compacted in one pass instead of lifts, or holding water. Patios need 4 to 6 inches of compacted Class II base and driveways need 8 to 12, screeded sand at 1 inch, and a quarter inch per foot of fall away from the house.
Last updated: August 2026
A homeowner off Ramona Expressway called us about a patio that had developed a dip near the slider. Three years old. Set of nice pavers, tight joints, and a two-inch belly right where everybody walks.
We pulled a section. Two inches of base under it, and the bottom inch was still loose enough to scrape with a finger.
What we find under failing patios
Almost always one of three things, and usually two of them together.
Base depth. Two or three inches works on a stable subgrade in a mild climate. Inland Empire clay is not stable subgrade. It swells with winter rain and shrinks in a Hemet August, and a thin base just rides that movement.
Compaction. Rock dumped 5 inches deep and run over once with a plate compactor gives you a hard crust and soft material underneath. It has to go in lifts, roughly 2 to 3 inches at a time, wet, with a pass over each one. Skipping the second lift saves an hour and costs the customer the patio.
Water. Pavers are permeable by design. Whatever passes through the joints needs somewhere to go. If the base sits in a bathtub of clay with no fall and no drain, the fines wash into the low spot and the pavers follow them down.
The tell before it sinks
Efflorescence and joint sand disappearing from one specific area usually shows up before the dip does. Sand migrating means water is moving through that spot faster than the rest of the patio. That is where it will settle.
How we build a patio that stays put
- Excavate to full depth, 4 to 6 inches of base for a patio, 8 to 12 for a driveway that will hold a truck.
- Compact the subgrade before any rock goes down.
- Class II base in 2 to 3 inch lifts, wet, compacted separately each time.
- Screed 1 inch of bedding sand. Not more. Thick sand beds are a settling problem waiting to happen.
- Set pavers, install spiked edge restraint on every open side, compact the field, then sweep polymeric sand into the joints and set it with a light mist.
Grade matters as much as depth. A quarter inch of fall per foot away from the foundation is the number we work to. On the older San Jacinto tracts where the yard was already graded toward the house, that means cutting more than the customer expected. We would rather have that conversation at bid time than dig the patio out later.
Can a sunken patio be repaired?
Yes, and it is usually not a full tear-out. Pavers lift, get stacked, the failed base gets rebuilt properly, and the same pavers go back down. You lose some to breakage on the lift and joint sand has to be redone across the repaired area, so it never blends perfectly on a weathered patio.
What we will not do is throw sand in the dip and re-lay the same pavers over the same bad base. It looks fixed for one season.
Summer storms are what expose all of this. The valley gets very little rain and then gets an inch in forty minutes, and every drainage shortcut on a property announces itself that afternoon.
More on paver work: paver vs concrete patio cost, why new pavers get a white haze, maintaining pavers in desert heat, and our paver patio and driveway page.