At a Glance
Reactive clay soils across much of Adelaide's north and south create persistent stump movement that eventually shows up as sloping floors and wall cracks. Structural repair work in Adelaide typically costs $2,550–$21,250 per job, covering restumping, bearer and joist replacement, subfloor repairs, and load-bearing wall modifications.
What's Included in the Price
A structural repair quote covers damage assessment, removal and replacement of affected stumps, bearers, and joists, re-levelling the house, and temporary support during the work. All timber framing must comply with AS 1684 Residential Timber-Framed Construction. Engineering is typically required, particularly for restumping on reactive soils and any load-bearing modifications. The engineer's fee may be included in the builder's quote or charged separately.
Materials include replacement stumps (concrete or steel screw piles), new bearers and joists, and fixings. On Adelaide's reactive clay soils, steel screw piles are increasingly specified because they can be driven past the reactive zone into stable ground. Labour is the dominant cost component, with temporary propping and re-levelling requiring skilled work and careful sequencing.
What Affects the Cost
- Number of stumps. Replacing 10–15 failed stumps in one area of the house is a fraction of a full restump covering 40–60 stumps.
- Stump material. Concrete stumps are the traditional choice. Steel screw piles cost more per unit but are better suited to Adelaide's reactive clay soils because they anchor below the zone of seasonal moisture change.
- Crawl space access. Adelaide has many low-set homes with limited subfloor clearance. Working in a 300mm crawl space takes significantly longer than in a generous 600mm+ space.
- Soil reactivity. Adelaide's northern plains and southern suburbs sit on highly reactive clay that expands and contracts with seasonal moisture. This puts ongoing stress on stumps and can mean deeper footings or longer piles for replacements.
- Extent of timber damage. A few rotten bearers in one section is a contained job. Widespread damage across the subfloor frame, particularly from prolonged moisture or termite activity, multiplies the scope.
- Engineering requirements. An engineer's assessment adds $500–$1,500+ to the project. For reactive soil sites, the engineer may specify deeper footings or a different stump system than what was there originally.
- Asbestos. Pre-1990 homes may have asbestos sheeting in subfloor areas, cladding, or around wet areas. Licensed removal is required before structural work can proceed.
Replacing a handful of deteriorated stumps under a raised home with reasonable subfloor access on stable ground sits toward $2,550. A full-house restump with bearer and joist replacement, steel screw piles, engineering for reactive soils, and asbestos removal in a low-set home pushes toward $21,250.
Adelaide-Specific Considerations
Reactive clay soils in the north and south. Salisbury, Elizabeth, Parafield Gardens in the north; Morphett Vale, Reynella, Hackham in the south. These suburbs sit on some of Adelaide's most reactive clay soils. The ground expands significantly during wet winters and contracts through dry summers, creating seasonal cycles of movement that push stumps out of alignment over years. Homes built in the 1950s–1970s on these soils are the most affected, as original stumps were designed for less extreme conditions than some properties have experienced.
Bluestone and mixed-construction homes. Adelaide's inner suburbs (Norwood, Unley, Prospect, Goodwood) feature a distinctive housing stock: bluestone fronted homes from the 1880s–1910s with mixed masonry and timber framing. The bluestone walls themselves are durable, but the timber subfloor framing, internal walls, and rear additions are susceptible to the same deterioration as any timber-framed home. Structural assessment of these properties needs to account for the interaction between the masonry and timber systems, which behave differently under ground movement.
Adelaide Hills properties. Stirling, Crafers, Mount Barker, Aldgate. Homes built on steep hillside blocks in the Adelaide Hills face additional structural complexity. Sloping sites mean uneven stump heights, more extensive subframe bracing, and potential retaining wall interactions. Access for equipment can be restricted by steep driveways and narrow blocks. The cooler, wetter microclimate in the Hills also promotes moisture retention in subfloor timbers, accelerating deterioration compared to the drier plains suburbs.
Post-war housing stock. Adelaide's rapid suburban expansion through the 1950s–1970s produced large numbers of timber-floored homes on concrete stumps. In areas with reactive soils, these homes are now the right age for stump failure to become visible. Common symptoms include doors that no longer latch, visible gaps between skirting boards and floors, and cracks appearing in plaster walls. These are signs of differential movement, where some stumps have settled or shifted more than others.
Smaller trade pool. Adelaide has a smaller pool of structural builders and restumping specialists compared to Melbourne or Sydney. This can mean longer wait times for quotes and scheduling, particularly during busy periods after extended wet weather when demand spikes. Getting three quotes is still the right approach, but allow more lead time.
Hiring a Licensed Carpenter in SA
In South Australia, a Building Work Contractor's Licence is required for structural building work. The licence is issued by Consumer and Business Services (CBS). Verify a contractor's licence through the CBS licence search.
Ask for:
- Current SA Building Work Contractor's Licence number (verify it online)
- Proof of public liability insurance
- A written quote specifying scope, stump material, and whether engineering is included
- Engineer's assessment or confirmation one will be arranged
- Confirmation of council or building approval requirements
Red flags: No contractor's licence, unwillingness to involve an engineer for structural work, or no consideration of soil conditions when specifying replacement stumps. In SA, building indemnity insurance is required for domestic building work over $12,000.
How We Calculate
Estimates are based on current licensed builder and carpenter rates across the Adelaide metropolitan area, adjusted for material and engineering costs in SA. All prices include GST. Figures cover standard residential structural repair work. Heritage-listed properties, commercial buildings, and Adelaide Hills properties on steep sites may fall outside these ranges.