If your floors have started sloping or your doors have stopped closing, you will quickly run into two words that get used as though they mean the same thing. They do not. Restumping and underpinning address different problems on different types of construction, and getting the diagnosis right matters more than getting a quick quote.
Here is how to tell which conversation you should be having.
The difference comes down to what is holding the house up
A house on stumps sits above the ground on individual piers, with a timber floor structure spanning between them. Restumping means replacing those stumps and re-levelling the house on the new ones. It is a well-established job with a predictable method.
A house on a concrete slab sits directly on the ground, with the slab itself doing the work. There are no stumps to replace. When a slab moves, the fix is underpinning, which means going beneath the existing footing and transferring the load onto something more stable further down.
So the first question is not what is wrong with your house. It is what your house is built on.
Which is which around Wyndham
Melbourne's west has both, and roughly along generational lines.
The older housing stock through central Werribee, Werribee South and the established parts of Hoppers Crossing includes a good number of stumped homes, particularly weatherboard and older brick veneer on timber floors. These are restumping candidates.
The newer estates that have spread across Tarneit, Point Cook and the growth corridor over the last few decades are overwhelmingly slab-on-ground. If your house was built in the last thirty years or so, it is almost certainly a slab, and restumping is not a service that applies to it.
If you are not sure, there are two simple indicators:
- Likely stumped — there is a subfloor you can get under, air vents sit low on the external walls, and the floors feel slightly springy underfoot.
- Likely a slab — the house sits low to the ground, there are no subfloor vents, and the floors feel completely solid.
Why both problems happen here
The underlying cause is frequently the same, which is part of why the two get confused.
Wyndham sits on highly reactive clay soils. These soils take up water and swell in the wet, then dry out and shrink in summer, and the movement is substantial. Everything built on them experiences that movement.
On a stumped house, the movement pushes and drops individual stumps, and because each one moves independently, the floor above goes out of level unevenly. Older timber stumps compound this by rotting at ground level, which is where moisture sits.
On a slab, the same soil movement lifts and drops sections of the slab, which is what causes cracking through walls and floors. The slab does not fail because it is weak; it fails because the ground under one part of it moved differently from the ground under another.
Prolonged dry spells, large trees drawing moisture from beneath the footprint, and poor drainage against the house all accelerate either version.
The symptoms overlap
This is the frustrating part. Many of the warning signs are common to both.
- Doors and windows that stick or will not latch.
- Cracks in plaster, particularly running diagonally from door and window corners.
- Gaps opening between skirting boards and the floor, or between cornices and the ceiling.
- Visible slope when you put a ball on the floor and it rolls.
What differs is what you find underneath. On a stumped house, an inspection of the subfloor will show stumps that have rotted, sunk, tilted or lost contact with the bearer above. On a slab, there is nothing to inspect underneath, and the assessment relies on level surveys across the floor, crack patterns and soil investigation.
That is why the inspection matters. The symptoms will not tell you which job you need. The construction will.
What restumping actually involves
On a stumped house, the process is methodical. The subfloor is assessed and every stump checked. The house is then supported on jacks while the failed stumps are removed and new ones installed with properly sized footings, and the house is progressively brought back to level.
Modern replacements are either precast concrete or galvanised steel. The choice between them is a genuine decision with trade-offs, and worth its own conversation, but both substantially outlast the timber stumps they are replacing.
Re-levelling is generally done gradually rather than all at once, because moving a house too quickly cracks the plaster and brickwork that has settled into its current shape over years. A careful job produces less internal damage to make good afterwards.
Most homeowners can remain living in the house through the work, which is not always true of the alternative.
What underpinning involves
Underpinning is a heavier engineering exercise. It generally requires a geotechnical investigation and an engineer's design before anything starts, because the solution depends on how deep stable ground sits beneath the site.
It is more expensive than restumping, takes longer, and involves excavation around and under the house. It is also not something to undertake on a diagnosis alone, because the design has to match the actual soil profile of your site.
Deal with the water first
Whichever fix you eventually need, the cause is usually water, and addressing it protects the repair.
Downpipes discharging beside the footing rather than into stormwater, blocked or leaking drains, garden beds banked up against the house, and irrigation running close to the perimeter all concentrate moisture in exactly the wrong place. Large trees close to the house draw moisture out unevenly and are a common contributor on reactive clay.
Fixing the drainage without fixing the structure will not re-level a house. But fixing the structure without fixing the drainage means doing it again.
Getting a straight answer
The useful first step is an inspection that tells you what your house is built on, what the actual condition beneath it is, and whether the movement is active or historic. That determines which of these two jobs is even on the table.
Be wary of anyone quoting a solution before establishing that, and particularly of anyone offering to restump a slab-on-ground home.
Our restumping and house re-levelling work covers Werribee, Hoppers Crossing, Tarneit, Point Cook and Altona Meadows, and the inspection comes first — including telling you plainly when what you are seeing is seasonal timber movement rather than something that needs a structural fix at all.