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, which provides span tables graded by timber stress grade (F7, F17, MGP10, MGP12). Where stumps or footings are being replaced on reactive clay, the footing design must comply with AS 2870 Residential Slabs and Footings, which classifies Adelaide sites from A (non-reactive, uncommon outside the Hills) through M, H1, H2, to E (extremely reactive, over 75mm ground movement).
Engineering is typically required, particularly for restumping on reactive soils and any load-bearing modifications. A structural inspection runs $490–$1,000, with full engineering designs for wall removal or complex restumping running $1,500–$3,000+. Materials include concrete stumps ($400–$700 installed), steel screw piles ($500–$1,000 installed, preferred on reactive clay because they anchor past the reactive zone), and replacement bearers and joists in hardwood ($20–$50 per lineal metre for F17 grade) or treated pine ($8–$20 per lineal metre for H3/H4). 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. At $400–$1,000 per stump installed (depending on material and access), the stump count is the primary cost driver.
- Stump material. Concrete stumps ($400–$700 installed) are the traditional choice. Steel screw piles ($500–$1,000 installed) cost more per unit but are increasingly preferred on Adelaide's reactive clay because they anchor below the zone of seasonal moisture change. Adjustable galvanised steel posts from brands like LevelMaster (bolted to concrete pads, fully above ground) are another option for accessible subfloors.
- 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, potentially adding 30–50% to labour costs.
- Soil reactivity. Adelaide's northern plains and southern suburbs sit on highly reactive clay. Under AS 2870, many of these sites are classified H1 or H2, meaning 40–75mm of seasonal ground movement. This can mean deeper footings, longer screw piles, or an engineered footing design, adding $1,000–$3,000 to the project.
- Extent of timber damage. A few rotten bearers ($500–$1,000 per bearer) in one section is a contained job. Widespread damage across the subfloor frame, particularly from prolonged moisture retention or termite activity, multiplies the scope substantially.
- Engineering requirements. A structural inspection ($490–$1,000) is the starting point. For reactive soil sites, the engineer may specify deeper footings, a different stump system, or additional bracing. For load-bearing wall removal, LVL beams (Wesbeam E13/E14 at $15–$40/lm) or steel UB sections ($200–$500/lm) are specified by the engineer.
- Asbestos. Pre-1990 homes may have asbestos sheeting in subfloor areas, cladding, or around wet areas. Licensed removal ($1,500–$5,000) 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, One Tree Hill in the north; Morphett Vale, Reynella, Hackham, McLaren Vale 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 progressively out of alignment. Under AS 2870, many of these sites are classified H1 (40–60mm movement) to H2 (60–75mm movement). Homes built in the 1950s–1970s on these soils are the most affected, as original stumps were not designed for the cumulative effects of decades of reactive clay movement. Companies like Foundation Repair Adelaide specialise in restumping on reactive soil sites and can assess whether screw piles or concrete stumps are better suited to your specific soil classification.
Bluestone and mixed-construction homes. Adelaide's inner suburbs (Norwood, Unley, Prospect, Goodwood, Hyde Park, Colonel Light Gardens) feature a distinctive housing stock: bluestone-fronted homes from the 1880s–1910s with mixed masonry and timber framing. The bluestone walls themselves are remarkably durable (bluestone is a basalt with excellent compressive strength), 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 how the masonry and timber systems interact under ground movement. The masonry is rigid while the timber flexes, meaning differential movement between the two can cause cracking at the junction points. A good structural engineer will specify fixings and connections that allow for this differential movement.
Adelaide Hills properties. Stirling, Crafers, Mount Barker, Aldgate, Bridgewater, Hahndorf. Homes on steep hillside blocks face additional structural complexity. Sloping sites mean uneven stump heights (some stumps may be 300mm while others are 1,500mm on the same house), 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. Stumps on the downhill side of sloping blocks carry greater lateral loads and are more prone to displacement.
Post-war housing stock. Adelaide's rapid suburban expansion through the 1950s–1970s produced large numbers of timber-floored homes on concrete stumps, particularly across the northern suburbs (Modbury, Tea Tree Gully, Ingle Farm) and western suburbs (Woodville, Findon, Seaton). 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 stepped cracks appearing in brick veneer walls. These are signs of differential movement, where some stumps have settled or shifted more than others.
Smaller trade pool and longer lead times. 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 for restumping spikes across the northern and southern suburbs simultaneously. Getting three quotes is still the right approach, but allow 4–6 weeks lead time for scheduling, longer during peak demand.
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.
A good structural builder will:
- Provide their current SA Building Work Contractor's Licence number (verify it online before signing)
- Carry public liability and building indemnity insurance (mandatory for domestic work over $12,000 in SA)
- Give a written quote specifying scope, stump material, bearer/joist species and grade, and engineering scope
- Arrange an engineer's assessment appropriate for your soil conditions
- Confirm council or building approval requirements
Worth checking:
- The licence is current and covers building or carpentry work
- The quote specifies stump material appropriate for your soil classification (screw piles for H1/H2 sites, not just standard concrete)
- Engineering is arranged for any restumping or load-bearing modification
- The builder explains what cosmetic damage to expect during restumping and budgets a 10–20% contingency for hidden damage
- Building indemnity insurance is provided for jobs 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.