Why your paver patio is sinking, and whether it can be saved

Pavers themselves almost never fail. They’re concrete blocks — they’ll outlast most of us. When a patio goes wrong, it’s the few inches underneath it that gave way.

The useful question isn’t why is it sinking, it’s how much of it is sinking, and where. That determines whether this is an afternoon or a rebuild.

#Three patterns, three different jobs

A dip in one spot, everything else flat. Usually a localized base failure — a soft pocket that wasn’t compacted, or a spot where water has been washing fines out. Lift, re-compact, re-screed, re-lay. Straightforward.

Sinking along one edge, with pavers creeping outward. The edge restraint has failed or was never installed. Without restraint the whole field slowly spreads, joints open, and the edge drops. Fixable, but you’re resetting the perimeter.

The whole thing settling evenly, or heaving in winter. Insufficient base depth or no drainage. That is a rebuild. Nothing you do at the surface fixes a four-inch base under a driveway.

#Where the water is going is the real diagnosis

Go out during or just after a heavy rain, or run a hose on it.

Water should run off the surface, at a slope of roughly a quarter-inch per foot away from the house. If it puddles, or runs toward the building, or disappears down between the pavers and doesn’t come back out, that’s the mechanism.

Water moving through the base carries the fine material with it. Lose the fines and the base loses its structure. That’s why sinking accelerates — it starts slow, then goes fast.

#Freeze-thaw is why this happens faster here

At our elevation the ground freezes and thaws repeatedly through the winter, not just once. Every cycle lifts saturated base material and drops it back slightly differently.

A base built with proper depth and drainage has nowhere for water to sit, so there’s nothing to freeze. A thin base over native soil holds water all winter and gets worked like a jack.

This is the whole reason base spec matters more here than in a mild climate — and why an installer’s quote from somewhere without frost isn’t a useful comparison.

#What to ask before anyone lifts a paver

1. How deep is the existing base, and what is it? Dig a test hole at the edge. Road base or sand? Four inches or eight?
2. Is there edge restraint? Look at the perimeter. Spiked plastic or metal, or nothing?
3. Is the joint sand still there? Empty joints let water straight in and let pavers rock.
4. Where does the water go?

A contractor who re-lays your pavers without answering those is selling you the same failure again in three years.

#Roughly what to expect

Re-leveling a localized dip is a modest job. Resetting a perimeter with new restraint is bigger. A full rebuild means excavating out the old base and starting again — and at that point the honest advice is often that it costs more to fix badly than to do once properly.

We’ll tell you which one you’re looking at before we quote it, including when the answer is “leave it, it’s cosmetic.”

We install and repair pavers across the Carson Valley. Send us a photo and we can usually narrow it down before we even come out.