Screw piles vs concrete vs resin vs house levelling: comparison

Grounded in this site's own cost guide and cost estimator, plus published Australian contractor and standards sources. General information, not advice for your specific property.

Cost, timeline, durability and the situations each one suits, side by side, so you know what to expect before an engineer or contractor recommends a method.

There is no single best underpinning method. The right one depends on the soil, the depth to stable ground, site access, and how much of the building has moved, which is exactly why a structural engineer's diagnosis should come before any method is chosen. This page puts the four methods homeowners are most commonly quoted, screw piles, mass concrete underpinning, resin injection, and house levelling by restumping, side by side on cost, timeline, durability and fit, using the same figures already published in this site's cost guide and cost estimator.

Method comparison at a glance

Every figure below is an indicative guide aggregated from published Australian sources, not a quote. Method choice should follow a structural engineer's assessment, not the other way around.

Screw piles / steel piers

Steel screw piles, also called helical piles, are wound into the ground until they reach a load-bearing stratum or a set torque resistance, then brackets transfer the footing's load onto them. Pricing is per pile, commonly in the low thousands each, with the number needed depending on the length of footing the engineer's design specifies; for deep or difficult ground, engineered mini-piled underpinning runs $10,000 to $20,000 per pile on its own. Because there is no concrete to cure, a pile can typically be loaded as soon as it reaches design depth, which is why installers describe screw piles as often going in noticeably faster than an equivalent concrete job, avoiding the 3 to 28 days of curing delay that concrete underpinning can add between stages. Properly designed and installed screw piles are commonly described as having a service life of 50 years or more, matching the expected life of the building itself.

Mass concrete (pit) underpinning

The traditional method: crews excavate a pit beneath the existing footing down to firm soil and fill it with concrete, working in small, carefully sequenced sections so the wall is never left unsupported. It is priced by the linear metre of wall, commonly $1,000 to $3,000 per metre (Mainmark's published figure), which is why the total scales fairly directly with how much of the footing needs support. It needs no specialised piling plant, which suits tight-access sites, but it is generally the slowest of the four methods here, both because of the staged excavation and because each section needs time to cure before the next is opened up. Once built, it is simply a new section of footing, so it carries the same durability expectations as any correctly designed and built reinforced or mass concrete footing under Australian concrete standards, intended to last as long as the structure it supports.

Resin injection

An expanding structural resin is injected through small tubes into the soil beneath a footing or slab, compacting weak soil, filling voids, and in some cases gently re-levelling the structure, all without excavation. It is usually quoted per injection point or per square metre rather than a flat per-metre rate, and is often the cheapest option among the four where it suits the soil and problem. It is also the fastest by a wide margin: a typical house is commonly completed within one to two days, and treated surfaces are trafficable within hours rather than the days concrete needs to cure. The trade-off is track record: it is the newest of the four methods, so it does not yet have the multi-decade performance history of piling or mass concrete. The manufacturer describes the cured resin as remaining inert in the ground to continue supporting the structure for many years, but how well that holds up depends on soil stability and the specific product, and it is not a substitute for a piered method on heavily loaded footings or deep-seated movement, which is exactly the call a structural engineer makes.

House levelling: restumping and reblocking

For older homes built on timber or concrete stumps rather than a slab, the equivalent job is restumping (replacing all the stumps) or reblocking (replacing or resetting only the failed ones), which brings the floor back closer to level. It is priced per stump, commonly $500 to $700 each, with a wider reported range depending on stump material and how hard the stumps are to access. A full restump commonly runs $5,000 to $20,000, and can reach $10,000 to $30,000 for larger or high-set homes with more stumps to replace; a full restump typically takes about seven to nine days depending on house size, while reblocking just a few stumps can take as little as one to three days. Durability depends heavily on the material used: timber stumps are commonly reported to last as little as 20 years in wet soil (longer in drier, better-drained conditions), while concrete or galvanised steel replacement stumps are commonly rated for 50 years or more, which is why most restumping jobs today use steel or concrete rather than timber.

Which method suits your situation

• Deep stable ground, or you want the fastest install without excavation: screw piles are usually the fit, subject to an engineer confirming the design.
• Shallow to moderate depth to stable ground and tight site access: mass concrete underpinning is the well-understood default.
• A slab that has dropped or a void under it, and the movement is minor to moderate: resin injection is often quoted first, if an engineer confirms it suits the cause.
• An older home on timber or failing stumps with an uneven or sunk floor: house levelling by restumping or reblocking, not underpinning in the excavation sense, is the relevant job.
• Not sure which applies to you: that is exactly what a structural engineer's inspection is for, before any contractor quotes a method.

Common questions

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