Most of the houses we work under are timber homes on stumps. But regional Victoria and Queensland are also full of brick and brick-veneer homes built on concrete slabs or strip footings — and when those homes crack, sink at a corner or drop a wall line, the fix isn't restumping. It's underpinning: strengthening, deepening or re-supporting the existing footings so the house stops moving.
What underpinning actually is
Underpinning transfers the weight of your house from a failed or inadequate footing down to deeper, more stable ground. Depending on the method, that means excavating and pouring new concrete beneath the existing footing, installing steel screw piers to solid strata, or injecting an expanding structural resin under the footing to fill voids and re-level. All three do the same fundamental job — give the footing something solid to stand on — and the right one depends on your soil, the damage pattern and the engineer's assessment, not on which truck turns up first.
The signs a slab or strip-footing home needs underpinning
- Stepped or zigzag cracks in external brickwork — the classic subsidence signature. Masonry doesn't flex; it breaks along the mortar lines.
- Cracks wider than about 5mm, or cracks that keep growing after being patched.
- Doors and windows jamming in a brick home, or gaps opening around their frames.
- A sinking corner or dipping floor on a concrete slab — often where a downpipe, leaking pipe or big tree has changed the soil moisture.
- Gaps between the slab edge and paving, or brickwork rotating away from the frame.
One hairline crack that opens and closes with the seasons is usually just reactive soil breathing. Cracks that ratchet wider every year, cluster at one corner, or step through multiple brick courses are the footing losing the battle — and the earlier underpinning happens, the smaller and cheaper the job.
Underpinning vs restumping — get this right first
The two get confused constantly, and some contractors let the confusion pad the invoice. The test is simple: what is your house standing on?
- Timber floor over a crawl space, house on stumps (most older weatherboards and Queenslanders): you need restumping — replacing the stumps. Typical full jobs $9,000–$22,000.
- Concrete slab or strip footings, no subfloor (most brick and brick-veneer homes from the 1970s on, and many older solid-brick homes): footing problems here are underpinning territory — different method, different engineering, different price bracket.
- Brick-veneer on stumps (common regionally): usually restumping — the timber frame carries the load and the brick skin is cladding. An inspection sorts it in minutes.
What underpinning costs in 2026
Underpinning is priced per metre of wall underpinned or per pier installed, and honest published Australian figures cluster tightly:
| Method | Typical 2026 pricing | Notes |
|---|---|---|
| Traditional concrete underpinning | $1,500–$3,000 per lineal metre | Excavated pits, poured mass-concrete pins beneath the footing |
| Steel screw piers | $3,500–$5,500 per pier | Driven to refusal on solid strata; good in deep soft soils |
| Resin injection | $4,000–$16,000 typical whole job | Fast (1–2 days), minimal excavation; suits void-filling and modest re-levelling |
| Typical residential project (total) | $12,000–$30,000+ | Most single-corner or single-wall jobs |
| Severe or whole-perimeter subsidence | $40,000–$80,000+ | Multiple walls, deep founding, difficult access |
| Geotechnical (soil) report | $1,000–$3,000 | Bore holes classify the soil and set founding depth |
| Structural engineering | $500–$3,000 | Assessment through to full underpinning design |
So the realistic bracket for most homes is $10,000–$40,000+, with small resin jobs under that and severe cases above it. Corner-of-house jobs (three or four metres of wall) sit at the bottom of the range; a full wall or multiple walls climbs fast. As with restumping, the cheap quote that skips the geotech report and engineering isn't cheap — it's incomplete. For an itemised range built from your extent, method and access, try the underpinning cost calculator — same published rates as this table, 30 seconds.
Concrete or resin?
Traditional concrete underpinning is the heavyweight fix: pits are hand-excavated beneath the footing in a staged sequence and filled with mass concrete, founding the wall on deep, stable ground. It's proven, permanent, and the default where subsidence is severe, founding depth is deep, or the structure is heavy. It's also slower — days to weeks of staged excavation and curing.
Resin injection pumps an expanding structural resin through small holes into the ground beneath the footing, filling voids, compacting weak soil and — done carefully — lifting the footing back toward level. It's fast, tidy and often significantly cheaper, but it treats the ground rather than deepening the footing, so it suits void-filling and moderate movement in the right soils, not every job. Screw piers split the difference where solid strata sits deep. The engineer's report — not a salesperson — should pick the method. If a contractor only sells one method, get a second opinion on whether it's the method your house needs.
Engineering, geotech and permits — non-negotiable
Underpinning without engineering is guessing with concrete. A proper job starts with a geotechnical investigation (bore holes that classify your soil and find stable founding depth) and a structural engineer's design specifying pin locations, depths and sequence. In Victoria, underpinning is structural building work requiring a building permit from a registered building surveyor; in Queensland it needs building approval from a private certifier, and foundation work like constructing underpinning is licensed QBCC territory. We arrange the geotech, the engineering, the permit and the mandatory inspections on every job — they appear as line items in the fixed quote, never as surprises.
How an underpinning job runs
- Assessment (free): crack mapping, floor levels, moisture and drainage check — and an honest call on whether it's underpinning, restumping, or just seasonal movement worth monitoring first.
- Geotech + engineering: soil classified, method and layout designed.
- Permit / certifier approval lodged — we handle it.
- The work: staged pins, piers or injection per the design, with engineer and surveyor inspections at the specified holds.
- Certification: completion paperwork that matters enormously when you sell a house with a documented, engineered subsidence repair.
Fix the cause too: underpinning a corner while the downpipe keeps soaking it is buying the same problem twice. Every assessment we do includes the drainage and moisture story, because that's usually where the movement started.