Why Is My Paving Sinking? Causes and Fixes

The five usual causes

Water in the base. A gutter emptying onto the paving, a leaking pipe, a blocked drain or a low spot where storm water collects. Wet base material loses strength and gives under load.
A thin or poorly compacted base. It settles under the weight of cars, usually along the wheel tracks and where cars park or turn.
No edge restraint. Without a kerb or concrete haunch, the outer pavers creep outwards, the joints open and the paving spreads.
Moving ground. Expansive clay swells when wet and shrinks when dry; collapsible soils settle when wetted under load. Both move whatever sits on them.
Tree roots. Roots growing under paving lift it, usually in a line running out from the tree.

Johannesburg's ground and its weather

Johannesburg's rain falls mostly between October and March, often as short, heavy afternoon thunderstorms, with December usually the wettest month. That is when water finds the weak points in paving. South Africa's housing guidelines recognise expansive soils, which heave and shrink with moisture, and collapsible soils, which can settle suddenly when loaded and wetted, as distinct ground classes, and both occur in Gauteng.

On the West Rand and East Rand, parts of the ground are underlain by dolomite, where engineers warn that concentrated water causes internal erosion. If paving on such ground keeps sinking in one place, get advice before you relay it.

Sources: timeanddate.com, Johannesburg climate averages (O.R. Tambo, 1992-2021); South African Weather Service media release, 12 November 2025; GGDA geotechnical investigation report (NHBRC site class designations); Stiff, Booyens and Mmileng (SRK Consulting), Protecting infrastructure from dolomite-related subsidence and sinkholes, Civil Engineering, April 2025

Reading the signs

Two parallel ruts: the base was too thin for the traffic.
A dip by a downpipe or tap: water is getting into the base at that point.
Outer blocks drifting into the garden: missing or failed edge restraint.
Waves across the whole surface: moving ground or a base that has failed throughout.
A raised line from a tree: roots.
Weeds and rocking blocks everywhere: joint sand has been lost.
A dip that grows fast, or a hole: stop and get professional advice.

How it should be fixed

A proper repair lifts the pavers in and around the failed area, finds and removes the cause, rebuilds and compacts the base, re-screeds the bedding sand, relays the pavers and fills the joints. If the cause was water, the repair must also change where the water goes: a channel drain, a downpipe connection or new falls. Adding sand under sunken blocks without doing this may look fine for a season and then fail again.

Where most of a driveway has failed, repeated repairs can cost more than a new base. See paving repairs and relay and driveway paving.

Before the storm season

If you notice pooling, washed-out joints or a new dip, deal with it before the heavy summer rain. Water that keeps entering a weakened base makes the damaged area grow. Clearing gutters, checking downpipes and refilling open joints in late winter are cheap ways to protect paving that is still sound.

Frequently asked questions

Can I fix sunken paving myself?

Small areas can be lifted, re-bedded and relaid by a careful DIYer, but if the cause is water or a weak base, fix that first or it will sink again.

Is sinking paving dangerous?

Usually it is just a nuisance. A dip that grows quickly, a hole or cracks in nearby walls need professional advice.

Why is water pooling on my paving?

The surface has settled or the falls were never right. Pooling softens the base and makes things worse.

Why is my paving sinking or lifting?