Concrete Footings in Australia: The Complete 2026 Guide

Concrete footings are the most common foundation system in Australia. From a single-storey weatherboard cottage in Tasmania to a slab-on-ground house and land package in Western Sydney, the load path almost always ends in poured concrete somewhere in the soil. This guide explains, in plain English, what concrete footings actually are, the main types used across Australian residential and light-commercial construction, what they cost in 2026, how AS 2870 and soil classification drive the design, and when an engineered concrete-free footing is a smarter choice.

What is a concrete footing?

A concrete footing is a structural element, usually made of reinforced concrete cast in place, that transfers load from a building or structure into the ground. In residential terms, every external wall, internal load-bearing wall, brick pier, deck post and pergola column needs a footing that:

• spreads the load over enough soil area that the ground can carry it without excessive settlement,
• sits deep enough to be unaffected by seasonal moisture movement in the soil,
• anchors the structure against uplift and lateral loads (wind, in particular), and
• complies with AS 2870 Residential Slabs and Footings, the relevant state building regulation and the National Construction Code (NCC).

The word “footing” is sometimes used loosely. Strictly, the footing is the concrete element; the foundation is the soil or rock the footing bears on. Australian engineers refer to the soil's bearing capacity, reactivity (its tendency to swell and shrink with moisture) and the design site classification, and then specify a footing geometry that matches.

Types of concrete footings used in Australia

Australian builders use a handful of standard concrete footing types. The right one depends on soil class, load, the shape of the building and access.

1. Strip footings

A continuous trench of reinforced concrete that runs underneath external and load-bearing internal walls. Typical residential strip footings are 300–600 mm wide and 400–1000 mm deep, with N12 or N16 reinforcement top and bottom. Used everywhere in Australia for brick-veneer and double-brick housing on Class A, S and M sites.

2. Pad footings

Isolated rectangular or square concrete pads that sit under individual columns or posts. Common under deck posts, pergola posts, carport columns, steel-framed sheds, internal piers under stumped floors and verandah posts. Typical pad sizes are 450 × 450 × 600 mm to 900 × 900 × 900 mm depending on load.

3. Raft slabs and waffle pods

A raft slab is a stiffened concrete slab-on-ground that combines the slab with integrated edge and internal beams. Waffle pod slabs, the variant used on most new project-builder homes in Australia, use polystyrene void formers to create a grid of ribs above ground level. AS 2870 governs the depth and reinforcement of the edge and internal beams based on the site class.

4. Bored concrete piers

Holes are augered into the ground using a post-hole digger or a truck-mounted bored pier rig, then filled with concrete and reinforcement. Diameters of 300–600 mm and depths of 1500–3000 mm are typical. Used on reactive clay where strip or pad footings would move seasonally, on sloping blocks, and underneath stumped floors. Common across Melbourne, Adelaide, Western Sydney, Brisbane's western corridor and Hobart.

5. Mass concrete footings

Large unreinforced or lightly-reinforced concrete blocks used for fence posts, signs, light retaining walls and free-standing pergolas. Cheap, but limited to small loads.

6. Concrete stumps

Pre-cast concrete stumps (typically 100 × 100 mm or 125 × 125 mm) bedded into the ground in concrete. Once standard across Queensland Queenslanders, Melbourne weatherboard cottages and Tasmanian timber homes; now largely replaced by adjustable steel stumps and concrete-free systems on restumping jobs because pre-cast concrete stumps cannot be re-levelled if the ground moves.

AS 2870 and Australian soil classes

AS 2870 is the Australian Standard that governs residential slabs and footings. Every new house and most extensions in Australia must be designed to it. The standard requires a geotechnical site investigation and assigns the site one of the following classifications:

• Class A – Acceptable. Most sand and rock sites. Little ground movement. Common on the WA coastal plain.
• Class S – Slightly reactive clay. Small ground movement. Common in coastal NSW and parts of Queensland.
• Class M and M-D – Moderately reactive clay or silt. Found through outer Sydney, Brisbane, Hobart and parts of Melbourne and Adelaide.
• Class H1, H1-D, H2 and H2-D – Highly reactive clay. Significant seasonal swell and shrink. The default classification for much of Melbourne's west (Werribee, Melton, Tarneit, Point Cook), Adelaide's plains, Western Sydney (Penrith, Blacktown) and parts of southeast Queensland.
• Class E and E-D – Extremely reactive clay. Found in localised pockets, often on black-soil plains.
• Class P – Problem site. Soft soils, fill, mine subsidence areas, landslip, abnormal moisture conditions or trees. Site-specific engineering design is mandatory; standard AS 2870 footing details cannot be used.

The more reactive the site, the deeper and stiffer the footing must be. On Class H and E sites, builders typically move from shallow strip footings to either a deep edge-beam raft slab, bored concrete piers founded below the active zone, or engineered pile footings.

How deep do concrete footings need to be?

There is no single answer, because depth is driven by soil class, load and the depth of the “active zone” (the soil layer that moves with seasonal moisture). As a guide:

• Deck pad footings: 600–900 mm on Class A, S and M sites; 900–1200 mm or deeper on Class H sites.
• House strip footings: 400–600 mm on Class A and S; 600–1000 mm on Class M.
• Bored concrete piers under stumped floors: 1500–2400 mm on Class H1, sometimes deeper on H2 and E.
• Pergola post footings: typically 600–900 mm, but the governing load is usually wind uplift rather than vertical load, so geometry and reinforcement matter more than raw depth.
• Pier and beam in reactive clay: pier toes founded below the active zone, generally 1.8–3.0 m deep.

For any structure requiring a building permit, depth must be specified on engineered drawings; do not rely on the table above for actual construction.

How concrete footings are installed

The installation sequence for residential concrete footings in Australia is broadly the same across every state:

1. Site investigation and soil test. A geotechnical contractor drills boreholes or augers test holes to determine soil profile, classification under AS 2870 and bearing capacity.
2. Engineering design. A structural engineer specifies footing dimensions, depth, reinforcement, concrete grade and any special founding requirements.
3. Council or building surveyor permit. Plans, the soil report and engineering documentation are submitted for a building permit (Victoria, Tasmania), a Complying Development Certificate (NSW), a building approval (Queensland, Western Australia, South Australia) or equivalent.
4. Excavation. Trenches for strip footings, holes for bored piers or pads are excavated. A building surveyor or engineer inspects the depth, founding material and dimensions before any concrete is poured.
5. Reinforcement. Steel reinforcement (deformed bar, mesh and trench mesh) is placed in the trench or hole, with cover provided by bar chairs or spacers.
6. Concrete pour. N20, N25 or N32 concrete is delivered by truck and placed into the excavation. Vibrators consolidate the concrete around reinforcement.
7. Cure. Concrete is left to cure for a minimum period (usually 5–7 days for strip footings before brickwork; 28 days to reach full design strength). On reactive clay sites, builders need to manage moisture during cure to prevent shrinkage cracking.
8. Inspection and sign-off. Reinforcement and depth are normally inspected before pour, and the completed footing inspected before the next stage of construction.

Concrete footing cost in Australia (2026)

The cost of concrete footings in 2026 varies widely by location, soil, access and labour availability. The figures below are indicative ranges, supplied and installed, for Australian residential projects:

Prices exclude soil test, engineering design fees, permit fees and excavation in rock or contaminated ground. Regional Australia and remote sites can sit well above these ranges. Always get an itemised quote.

Concrete footings – state-by-state notes

The Australian regulatory landscape is broadly consistent because AS 2870 and the NCC apply nationally, but each state and territory has its own administrative regime and typical soil conditions.

• Victoria. Building permits administered under the Building Act 1993 by a registered building surveyor. Reactive clay dominates Melbourne's west and north. Bored concrete piers and screw piles are both common. See our Victorian footing regulations guide.
• New South Wales. Approvals are either a Complying Development Certificate (CDC) or a Development Application (DA) with a separate Construction Certificate. Western Sydney sits on highly reactive shale and Bringelly clay; bored piers or deep stiffened slabs are typical. Sydney's eastern beaches are largely sandstone – shallow strip footings or pad footings on rock.
• Queensland. Building approvals through a private building certifier under the Building Act 1975. The wet tropics, cyclonic regions and reactive black soil plains all change footing requirements. Concrete stumps are still common on Queenslanders but adjustable steel and concrete-free systems are gaining share for new builds and restumping.
• South Australia. Adelaide's Plains are predominantly Class H reactive clay; raft slabs and bored piers dominate. Approvals via private certifier or council.
• Western Australia. Coastal Perth is largely sand – Class A – favouring shallow strip and pad footings. Hills suburbs in the Darling Range encounter rock close to surface. The WA Building Commission regulates work via a building permit pathway.
• Tasmania. A mix of clay, basalt and sandy soils. Hobart's older suburbs have many timber homes on stumps. Cold and wet winters extend concrete cure times and slow strip-footing work.
• ACT. Most suburban Canberra sites are Class M or H reactive clay. Footings are governed by the ACT Building Act and AS 2870.
• Northern Territory. Cyclonic wind loading is the dominant design driver. Footings must resist substantial uplift; mass concrete and bored piers are both used, alongside engineered steel piling.

Common concrete footing problems

Concrete footings fail in well-understood ways. The most common Australian failure modes are:

• Reactive clay heave and shrink. Strip footings on Class H or E sites that were under-designed will move with the seasons, opening cracks in plaster and brickwork.
• Differential settlement. Different parts of a footing system settle by different amounts, producing diagonal cracking. Often caused by fill that was not properly compacted, or by piers that did not reach competent founding material.
• Tree-induced movement. Mature trees within proximity of the footings extract moisture from the soil, causing shrinkage and settlement. See our guide on footings near trees.
• Inadequate cover and rebar corrosion. Insufficient concrete cover over reinforcement leads to corrosion and concrete spalling, particularly within 1 km of the coast.
• Frost and freeze-thaw. Rare in Australia but relevant in the Tasmanian highlands and the Snowy Mountains: shallow footings can heave with freeze-thaw cycles.
• Cure-time damage. Concrete poured in extreme heat without curing measures, or in heavy rain, can crack and lose design strength.

Concrete footings vs engineered concrete-free footings

Engineered steel pile and screw pile footings – including the RapidStump, StumpRite and SurePile systems installed by Easy Footings – are an accepted alternative to bored concrete piers and pad footings under AS 2870 and the NCC. They are not a replacement for every concrete footing (you still need a slab for most houses), but they are demonstrably better than concrete in specific situations:

For a deeper comparison, read our concrete-free footings vs traditional concrete article and our screw pile footings guide.

FAQ – Concrete footings in Australia