Clear guide to choosing between strip footings and pad footings for Australian construction projects
Understand the key differences between strip footings and pad footings in 2026. This guide covers structural behaviour, design principles, when to use each type, typical dimensions, reinforcement requirements, AS 2870 and AS 3600 compliance, cost comparisons, and best practice for residential and commercial foundations in Australia.
A complete, practical comparison of the two most common shallow foundation types used in Australian residential and commercial construction in 2026
A strip footing (also called a continuous footing or wall footing) is a long, narrow concrete beam that runs continuously beneath a load-bearing wall. It distributes the wall's load over a linear strip of ground, spreading the pressure across a larger area than the wall alone. Strip footings are the standard foundation type for masonry and timber-framed walls in Australian residential construction under AS 2870, and are also widely used for boundary walls, retaining walls, and commercial tilt-panel buildings.
A pad footing (also called an isolated footing or column footing) is a discrete, square or rectangular concrete slab element that sits beneath a single column or post. It spreads the concentrated point load from the column over a sufficient area of bearing ground to keep the bearing pressure within safe limits. Pad footings are the standard foundation for steel and concrete columns in multi-storey buildings, industrial sheds, portal frame structures, and any building system where loads are transferred through isolated columns rather than continuous walls.
Choosing between a strip footing and a pad footing is a fundamental structural engineering decision that affects the entire superstructure design, excavation programme, concrete volume, reinforcement quantities, and overall foundation cost. The wrong choice can lead to differential settlement, structural cracking, or over-designed foundations that waste material and cost. In Australia, the choice is governed by the structural system, soil classification (AS 2870 Site Classes A through E and P), the column or wall layout, and the bearing capacity of the founding material at the specified depth.
The fundamental difference between a strip footing and a pad footing is the nature of the load being supported and how that load is distributed to the ground. Strip footings support linear loads from walls — loads distributed along a continuous line. Pad footings support point loads from columns — concentrated loads at a single location. This difference in load type drives every other difference in geometry, reinforcement, depth, and application.
In Australian construction practice, strip footings and pad footings are both classified as shallow foundations — they transfer load to near-surface soil layers rather than to deep rock or competent strata via piles. Both must comply with AS 2870 (Residential Slabs and Footings) for Class 1 and Class 10 buildings, and with AS 3600 (Concrete Structures) for engineered commercial and multi-storey applications. Understanding the structural requirements of each helps when reviewing structural assessment reports — see our Assessing Existing Concrete Structures Guide for related condition assessment methods.
Strip footings distribute load linearly beneath walls; pad footings distribute concentrated point loads from columns over a square bearing area. Both are shallow foundation types used extensively across Australia.
A strip footing works as a continuous inverted beam, receiving the wall load applied along its top and distributing it as a uniform bearing pressure across its bottom face in contact with the soil. The width of the strip footing is sized so that the applied bearing pressure does not exceed the allowable bearing capacity of the soil at the founding depth. The depth and reinforcement of the footing are designed to resist the bending moments and shear forces that develop within the footing cross-section as the soil reaction acts upward against the downward wall loads.
For a standard single-storey masonry home in Australia on a Class M site, strip footings are typically 300–450 mm wide and 300–400 mm deep. For double-storey masonry construction, widths of 450–600 mm and depths of 400–600 mm are common. Tilt-panel commercial construction requires engineered strip footings that may be 600–1000 mm wide and 500–700 mm deep depending on panel height, wind classification, and soil bearing capacity. All dimensions must be confirmed by a structural engineer for engineered construction.
Standard strip footings in residential construction under AS 2870 use longitudinal bars (typically 2–3 × N12 or N16 bars along the footing length) to provide continuity and resist differential settlement. Transverse bars or stirrups are added in higher-loaded commercial strip footings to resist shear and bending across the footing width. On reactive clay sites (Class M, H1, H2, E in AS 2870), additional longitudinal reinforcement is mandatory to allow the footing to act as a beam spanning across soft spots or soil voids caused by moisture movement.
Strip footings are the correct choice when the structure uses continuous load-bearing walls to transfer floor and roof loads to the foundations. This applies to: single and double-storey masonry veneer homes; full brick homes; concrete tilt-panel buildings; retaining walls; boundary fences with concrete footings; and commercial buildings with masonry or concrete load-bearing wall systems. The strip footing follows the full perimeter and all internal load-bearing wall lines of the structure.
On highly reactive clay soils — common in Melbourne, Adelaide, parts of Brisbane and regional Australia — strip footings must be specifically designed for soil movement under AS 2870 Site Classifications H1, H2, and E. Deeper footings (600–900 mm below ground) are often required to found below the active zone of moisture change. Increased reinforcement and stronger concrete grades (N25–N32) ensure the footing can span across zones of differential heave or shrinkage without cracking the walls it supports. Always obtain a geotechnical report to confirm site classification before strip footing design.
A pad footing works as a two-way bending plate in reverse — the column load is applied as a concentrated point at the centre of the top face, and the soil reaction pushes upward across the entire base area. This creates bending in both directions simultaneously (two-way bending) as the corners and edges of the pad tend to lift relative to the centre. The footing must be deep enough and reinforced in both directions to resist this two-way bending action without punching shear failure around the column base or flexural failure across any section through the footing.
For a lightly loaded steel post in a residential pergola or verandah, a pad footing may be as small as 450×450×300 mm. For a typical industrial shed portal frame column carrying 200–400 kN, a 1000×1000×400 mm to 1200×1200×500 mm pad is common. Multi-storey building columns carrying 1000–3000 kN require pad footings of 1800×1800×600 mm to 2500×2500×800 mm or larger depending on bearing capacity. For very large column loads on weak soils, combined footings or raft foundations may be more economical than large individual pad footings.
Pad footings are reinforced with a bidirectional grid of bottom bars in both plan directions to resist the two-way bending moments. The bar size and spacing are determined by the bending moment at the critical section (at the column face per AS 3600). Top reinforcement is added for larger, more heavily loaded pads where negative bending near the column creates tension in the top face. Starter bars projecting from the pad into the column above are lapped with the column longitudinal reinforcement to transfer the column load into the footing — starter bar size and lap length must comply with AS 3600 Table 13.1.7.2.
Pad footings are the correct choice when the structure uses columns or posts to transfer loads from beams, trusses, or slabs down to the foundations. This applies to: steel portal frame sheds and warehouses; multi-storey concrete or steel frame buildings; timber or steel deck structures on posts; freestanding canopies and carports; electricity transmission towers and masts; and any structure where loads concentrate at discrete points rather than along continuous walls. Each column has its own independent pad footing sized for its specific load.
Because pad footings are independent and not connected to each other (unlike strip footings which are continuous), they are more susceptible to differential settlement — where one pad settles more than adjacent pads, causing the beam or structure above to rack or crack. On variable soils, isolated pad footings must be sized conservatively and founded at consistent depth to minimise differential settlement. For large multi-bay structures on variable ground conditions in Australia, a geotechnical engineer's recommendation on whether to use isolated pads, combined footings, or a raft slab is essential before design commences.
The decision between strip footings and pad footings is primarily determined by the structural system above the foundation level. In practice, many Australian buildings use both types simultaneously — pad footings under columns and strip footings under walls — within the same foundation system. The table below summarises the key differences to assist engineers, builders, and designers in making the correct selection for their specific project.
| Parameter | Strip Footing | Pad Footing |
|---|---|---|
| Load type supported | Linear wall load (kN/m) | Point column load (kN) |
| Shape | Long continuous rectangular beam | Isolated square or rectangular slab |
| Structural system | Wall-bearing structures | Column-frame structures |
| Bending behaviour | One-way bending (transverse to wall) | Two-way bending (in both plan directions) |
| Typical width | 300–1000 mm | 450×450 mm to 3000×3000 mm |
| Typical depth | 300–600 mm (residential) to 700 mm+ (commercial) | 300–800 mm depending on column load |
| Reinforcement direction | Primarily longitudinal; transverse bars in commercial | Bidirectional bottom mesh; top bars where required |
| Excavation | Continuous trenching along all wall lines | Individual pit excavations at column positions |
| Concrete volume | Higher — follows all wall lines continuously | Lower for the same load — concrete only at columns |
| Differential settlement risk | Lower — continuous beam bridges soft spots | Higher — each pad independent, variable settlement possible |
| Connection to slab | Integral with edge beam of slab-on-ground in most residential construction | Separate element — column above, slab on ground typically independent |
| Australian Standard | AS 2870 (residential); AS 3600 (engineered) | AS 3600 (all engineered); AS 2870 (isolated residential posts) |
| Typical cost (residential) | $80–$150/lineal metre installed | $300–$1,200 per pad depending on size |
| Best for | Masonry homes, tilt panels, retaining walls | Steel sheds, multi-storey frames, portal structures |
For Class 1 and Class 10 buildings (homes and associated structures) in Australia, strip footing design is largely governed by AS 2870 Residential Slabs and Footings. This standard provides a prescriptive design approach for common residential configurations on sites classified from Class A (stable, non-reactive) to Class E (extremely reactive clay) and Class P (problem sites). Engineers and building designers can use AS 2870 tables to directly select strip footing widths, depths, and reinforcement without complex structural calculations for standard residential configurations.
The most common application for pad footings in Australian construction is beneath the columns of steel portal frame sheds, warehouses, and industrial buildings. Portal frame columns transfer both vertical gravity loads and horizontal wind and racking forces (base moments and shear forces) into the pad footing. This makes portal frame pad footings more complex than simple gravity-loaded column pads — they must resist overturning moments and horizontal shear in addition to vertical load, which typically requires deeper, heavier pads with top reinforcement and careful anchor bolt design.
In some Australian projects, conditions exist where neither a standard strip footing nor an individual pad footing alone provides the optimal foundation solution. A combined footing supports two or more columns on a single enlarged footing — typically used when column spacings are too small for individual pad footings without overlapping, or when one column is close to a property boundary and cannot be eccentric. A strap (tie) footing connects an eccentric boundary column pad to an interior column pad with a reinforced concrete beam to balance the eccentric soil pressure. These hybrid solutions are engineered to strict AS 3600 requirements and are relatively common in medium-density residential and commercial construction across Australian capital cities.
The cost of strip footings versus pad footings in Australia in 2026 depends on the building type, site conditions, soil classification, and regional labour and material costs. As a general rule, strip footings have a higher total concrete volume than pad footings for the same building footprint because they run continuously beneath all wall lines. However, strip footing excavation is simpler (continuous trenching) than pad footing excavation (individual pits at column positions), which can partially offset the higher concrete volume cost in some regions.
Supply and install of strip footings in Australia in 2026 typically costs $80–$150 per lineal metre for standard residential configurations on Class A–M sites, inclusive of excavation, formwork (where required), reinforcement, N25 concrete supply, and pour. On reactive Class H sites requiring wider, deeper footings with more reinforcement, costs rise to $130–$200+ per lineal metre. A standard 200 m² single-storey home with 80 lineal metres of strip footing runs approximately $8,000–$16,000 for the footing package depending on site class and region.
Individual pad footings in Australia in 2026 cost approximately $300–$600 for a small residential post pad (450×450×300 mm, hand-dug, minimal reo), $600–$1,200 for a medium industrial column pad (1000×1000×400 mm with reo and anchor bolts), and $1,500–$4,000+ for a large commercial pad (1800×1800×600 mm or larger). Machine excavation, dewatering, form complexity, and anchor bolt supply are the major cost variables. A 12-column industrial shed may have a total pad footing package cost of $10,000–$30,000 depending on column loads and soil conditions.
Strip footings and pad footings have similar construction durations for comparable-scale projects. Strip footing excavation by trencher or backhoe on a standard residential site takes 1–2 days; pouring and curing takes 3–7 days before the slab or masonry works above can commence. Pad footing excavation by backhoe for a 12-bay shed takes 1–2 days; placement of reo and anchor bolt cages takes 1–2 days; concrete pour and curing takes 3–7 days minimum before column erection. For programme-critical projects, early-strength concrete (HSC admixtures or N40 grade) can reduce the footing-to-frame gap to 2–3 days for both footing types.
AS 2870 Residential Slabs and Footings is the primary Australian Standard governing strip footing and pad footing design for Class 1 and Class 10 buildings. It provides prescriptive design tables for all site classifications (A through E and P) and covers slab-on-ground, waffle raft, stiffened raft, and footing beam systems in a single document. The current edition applicable in 2026 should be confirmed with Standards Australia before commencing any residential footing design.
Standards Australia →After strip footings and pad footings are poured and cured, correct backfilling technique protects the footing from lateral movement, maintains drainage, and ensures the footing performs as designed for the life of the structure. Our backfilling guide covers permitted backfill materials, compaction layer thicknesses, required compaction levels, and drainage provisions for both strip and pad footing configurations in Australian conditions.
Backfilling Guide →When existing strip footings or pad footings show signs of distress — cracking, settlement, heave, or corrosion — a structured assessment programme is required before remediation or underpinning can be designed. Our concrete structure assessment guide covers the full range of investigative tools applicable to existing footings, including core sampling, carbonation testing, rebar scanning, and bearing capacity assessment methods for Australian practice in 2026.
Assessment Guide →