Skip to content
LokalMatch

Foundation Repair

Foundation Repair near you

Foundation repair in Australia is mostly a soil problem wearing a concrete disguise. The National Construction Code requires a house to withstand the actions it will reasonably be subjected to, and the list of actions named for Class 1 buildings includes earth pressure, groundwater pressure, differential movement and settlement, and ground movement caused by soil swelling, shrinkage, landslip or subsidence. That last item is the one that keeps Australian foundation contractors in work.

Tell us about your foundation repair project and we’ll help you find local foundation contractors who serve your area.

Free for homeowners · No obligation to hire

On this page

The reason is reactive clay. Large parts of suburban Australia sit on clay soils that take up water and swell, then dry out and shrink, and a slab or strip footing sitting on that ground rises and falls with it. The Code answers this by requiring the foundations where footings and slabs are to be located to be classified in accordance with AS 2870, the Australian Standard for residential slabs and footings, which sorts sites from stable sand and rock through slightly, moderately, highly and extremely reactive clay to problem sites.

So the work ranges from correcting what is feeding moisture into one side of the house, through re-levelling and underpinning or piering a footing that has dropped, to structural strengthening designed by an engineer. This is also the trade with the most aggressive sales in Australian home services, so the guide below spends time on how movement is actually diagnosed and what an independent engineer's report gets you that a free inspection does not.

Signs your footings are moving, not just ageing

  • Doors and windows that bind, drop out of square or suddenly need forcing, especially when the change follows a long dry spell or a heavy wet period.
  • Cracks in internal cornices and plasterboard that open and close through the year rather than staying the same width.
  • Floors that slope, bounce or feel uneven underfoot, or a gap opening between the skirting and the floor along one wall.
  • External brickwork cracking in a stepped pattern through the mortar joints, or cracking that runs through the bricks themselves.
  • A wet area, paved area or garden bed on one elevation only, with the movement concentrated on that side of the house.
  • Gaps opening where a verandah, garage, carport or extension meets the original house, which is two structures on different footings moving apart.
  • A slab edge that has lifted or dropped relative to the paving or driveway beside it.

How movement is properly diagnosed before anything is repaired

A real diagnosis starts with the ground, not the crack. The site classification under AS 2870 tells you how much movement the house was ever designed to tolerate, and in Queensland site classification is regulated work in its own right: the QBCC lists site classification among the categories that require a licence at any value at all, alongside plumbing or drainage, gas fitting, chemical termite management, fire protection, completed residential building inspection, building design and mechanical services. In Victoria, the law approaches it from the contract side, requiring your builder to obtain foundation data, meaning a report based on soil tests recommending the depth of stumps or the type of slab or strip footing, before you sign a building contract.

The second step is measurement rather than opinion. A floor level survey across the whole footprint shows where the low and high points actually are, and repeating that survey months later shows whether the house is still moving and in which direction. Crack monitoring works the same way: mark, measure, photograph with a rule and a date, then look again after a long dry period and after sustained rain. Movement that reverses with the seasons is reactive clay behaving as expected; movement that only ever goes one way is settlement or subsidence and is a different problem with a different fix.

The third step is finding the moisture that is driving it. A leaking water service or sewer line under the slab, a downpipe discharging beside the footing, stormwater that has never been connected to a legal discharge point, a garden bed watered on one elevation, or a large tree drawing moisture out of the clay on one side of the house will each concentrate movement exactly where the damage is showing. Fixing the cause is often cheaper than the structural work, and structural work done without fixing the cause simply moves the crack.

Repair methods used on Australian slabs and footings

  • Moisture management first: correcting surface grades, downpipe discharge, leaking services and watering habits so the soil moisture around the footing stops swinging.
  • Underpinning, which the NSW licence definition describes as constructing a new support structure under a wall, column or footings of a building, used where a footing needs to reach more stable ground or carry more load.
  • Piering, described in the same definition as putting in a column or post to support a superstructure such as beams or floor bearers, common under suspended timber floors.
  • Screw or driven piles taken down to a stable stratum where the surface clay cannot be relied on.
  • Resin injection into the soil beneath a slab, used to lift and re-level, which is a geotechnical procedure and should come with before and after levels rather than a promise.
  • Restumping or reblocking a suspended floor, replacing failed timber stumps with concrete or steel and re-levelling the bearers.
  • Structural strengthening of the building above, such as tying or rebuilding cracked masonry and reinstating articulation joints so the structure can move without tearing.
  • Engineered redesign under AS 2870 or AS 3600 where the deemed-to-satisfy footing configurations in Section 4 of the ABCB Housing Provisions do not cover the site, since those configurations suit only the specified soil classifications.

A free inspection versus an independent engineer's report

Be clear-eyed about this market. A free inspection offered by a company that sells one repair method is a sales visit, and the person performing it is not independent of the answer. That does not make them dishonest, but it does mean the assessment and the quotation come from the same pocket, and the recommended solution tends to be the product the company installs.

An independent structural or geotechnical engineer is engaged by you and sells you nothing else. What you get for that fee is a description of what is actually happening, a cause, a specification of the remedy if one is needed, and a document that several contractors can price against. That last point is the practical one: without a specification, three quotes for foundation repair are three different jobs at three different numbers and cannot be compared. With one, they are competing on the same scope.

It also changes what happens if the repair does not work. A report prepared before the work, with levels and photographs, establishes the condition of the house at a point in time. If you later lodge a complaint, make an insurance claim or end up in a tribunal, that baseline is the difference between a documented case and a disagreement about what the house used to look like.

Licensing, permits and where LokalMatch fits

Licensing is set by each state and territory, and foundation work often needs a specific class rather than a general one. New South Wales issues underpinning and piering work as its own contractor licence category and requires a licence for residential building and trade work above the value threshold in the Home Building Act. Queensland requires a QBCC licence for building work above its threshold, and at any value for the categories listed earlier including site classification. Victoria registers building practitioners, and a building permit there is written approval from a registered building surveyor. Western Australia registers builders through the Building Services Board, as a practitioner registration for individuals or a contractor registration for those trading as builders, once permit-requiring building work reaches the set value for the building class.

Approvals are separate from licensing. Structural work, excavation near a boundary and anything affecting a neighbouring structure will usually need consent or a permit, and in Victoria it is the owner's obligation to ensure planning and building permits are obtained, whether you get them yourself or have your builder do it. Victoria also stops your builder appointing a private building surveyor on your behalf, which exists precisely so the person inspecting the work is not chosen by the person doing it.

LokalMatch sits at the start of that process and nowhere else. You describe the problem once, including what is cracking, when you first noticed it, what the house is built on if you know, and whether you already hold an engineer's report, and matched foundation contractors contact you directly. Those businesses pay for the requests they receive. LokalMatch does not carry out foundation work, does not set prices and does not vet, rank or recommend any contractor, so checking the licence class on the state regulator's own register, confirming insurance and comparing scopes remain yours to do.

Statutory cover, consumer guarantees and high-pressure selling

Where foundation work forms part of residential building work above the relevant state threshold, the statutory schemes apply. Queensland's Home Warranty Scheme insures residential construction work under fixed-price and cost-plus contracts, with the contractor paying the premium to the QBCC, cover commencing at the earliest of the contract being entered into, the premium being paid or work starting, and cover extending to non-completion, defective work and subsidence or settlement. The QBCC also warns that using an unlicensed contractor may void your access to that insurance, which is the most concrete reason to check a licence before signing. Victoria requires domestic building insurance above its threshold, with the policy and a certificate of currency given to you before any deposit or other money is taken.

Underneath all of that sit the Australian Consumer Law guarantees the ACCC enforces. Services must be provided with an acceptable level of care and skill, must be fit for any stated purpose, and must be supplied within a reasonable time if no time frame was agreed. Stating your purpose in writing, that the house is to stop moving and the doors are to close, makes the fitness guarantee concrete rather than theoretical.

On the sales side, know what is already illegal. The ACCC treats using physical force, coercion or undue harassment against a consumer as against the law, and describes unconscionable conduct as behaviour so harsh that it goes against good conscience, noting that knowingly targeting vulnerable people counts against a business. If the approach came to you unsolicited, at your door or by phone, the unsolicited consumer agreement rules apply: permitted contact hours, an obligation on the salesperson to give their name, the name and address of the business and why they are contacting you, a cooling-off period, and restrictions on taking payment during it. An offer that expires today, a price that only holds if you sign now, or a warning that your house is unsafe unless you act immediately is a reason to stop and get an independent report, not a reason to hurry.

Wet and dry: when Australian ground movement shows up

Because the driver is soil moisture rather than frost, the Australian calendar matters in a way northern guides get backwards. In the southern states the wetter, softer ground generally arrives through winter in June, July and August, while the hot months from December to February dry the clay out and shrink it. In the tropical north the split is the wet season against the dry. Either way, the damaging part is usually not the wet or the dry itself but the swing between them, and a long drought broken by sustained rain is when foundation complaints spike.

That has two practical consequences. The first is that a single inspection captures one moment in a cycle: a crack measured at the end of a dry spell will read differently after a wet month, which is why monitoring across seasons beats a same-day diagnosis. The second is that the cheapest intervention is often evening out the moisture, keeping watering consistent around the house rather than soaking one elevation, and making sure roof water leaves the site instead of soaking into the clay beside a footing.

Scheduling follows the same logic. Excavation, piering and underpinning are cleaner and safer in drier ground, so southern jobs tend to sit best in the drier months and northern jobs in the dry season, while an open excavation beside a footing during heavy rain is exactly the condition you do not want.

Foundation Repair: frequently asked questions

What is an AS 2870 site classification and why does it matter?

It is the classification of the ground your footings sit on, and the NCC requires it: foundations where footings and slabs are to be located must be classified in accordance with AS 2870. The classes run from sand and rock sites with little ground movement, through slightly and moderately reactive clay or silt, to highly and extremely reactive sites and problem sites, which are referred back to AS 2870 itself for design. It matters because it tells you how much seasonal movement your house was designed to tolerate, which is the yardstick for whether what you are seeing is normal or not.

Do I need an engineer, or will a foundation contractor's assessment do?

If structural movement is suspected, engage an engineer you pay directly. An engineer who is not selling the repair specifies what the problem is and what will fix it, which lets you compare quotes on one scope instead of comparing three different proposals. It also creates a dated baseline of levels and photographs that supports a warranty claim, a complaint or a tribunal application later.

A company knocked on my door and said my foundation is failing. What now?

Slow down. Unsolicited door-to-door and telephone sales are governed by the unsolicited consumer agreement rules the ACCC enforces, which set permitted contact hours, require the salesperson to identify themselves and their business and say why they are there, give you a cooling-off period and restrict taking payment during it. Coercion and undue harassment are against the law outright. Get an independent engineer's report before you sign anything.

Will fixing the drainage stop the movement on its own?

Sometimes, and it is almost always worth doing first. On reactive clay the damage comes from swings in soil moisture, so a downpipe discharging at the footing, an unconnected stormwater line, a leaking service or a garden watered on one elevation can be the whole cause. Correcting those is cheaper than structural work and, where the movement has not yet damaged the structure, may be all that is needed. Where the footing has already failed, drainage correction is still required so the repair is not undone.

Is foundation repair licensed work in Australia?

Yes, though the class varies by state. New South Wales has a specific underpinning and piering work licence category and requires a contractor licence above the Home Building Act value threshold. Queensland requires a QBCC licence above its threshold and at any value for listed categories including site classification. Victoria registers building practitioners and Western Australia registers builders through the Building Services Board. Ask which class covers your job and check the number on the regulator's own public register.

Does home warranty insurance cover foundation problems?

Where the work is insurable residential building work under a state scheme, it can. Queensland's Home Warranty Scheme covers defective work and subsidence or settlement, with the contractor paying the premium and cover starting at the earliest of the contract, the premium payment or the start of work, and the QBCC warns that using an unlicensed contractor may void access to it. Victoria requires domestic building insurance above its threshold, with the certificate handed over before any money is taken. Get the evidence of cover before work starts, not after.

Sources

  1. NCC 2022 Volume Two Part H1 Structure (structural performance, ground movement and AS 2870)
  2. NCC: ABCB Housing Provisions Part 4.2 Footings, slabs and associated elements (site classification to AS 2870)
  3. NCC: ABCB Housing Provisions Part 4.1 Scope and application of Section 4
  4. QBCC: Who must hold a QBCC licence
  5. NSW Government: Underpinning and piering work licence
  6. Consumer Affairs Victoria: Foundations and foundation data
  7. QBCC: What is home warranty insurance
  8. ACCC: Unfair business practices (unconscionable conduct and pressure selling)
  9. ACCC: Telemarketing and door-to-door sales (unsolicited consumer agreements)
  10. Western Australian Government: Builders' registration

Written by the LokalMatch editorial team. Last reviewed 14 September 2026. How we write and check our guides

What affects the cost of foundation repair

Prices depend on the details of your project. We only publish price ranges when they’re backed by real LokalMatch quote data or reliable sources. Until then, here’s what usually changes the price:

  • Interior or exterior approach
  • Length of foundation wall to excavate or treat
  • Depth, soil conditions and access for equipment
  • Crack repair, underpinning or other structural work
  • Weeping tile, sump pumps and backwater valves
  • Restoring landscaping, driveways or finished basements
  • Testing and safe removal of mould or asbestos, where needed

How to compare foundation contractors before you hire

  • Choose a contractor who finds the source of the water before recommending a fix, whether that's grading, eavestroughs, cracks or drainage.
  • Ask them to explain the difference between interior and exterior waterproofing for your home, and why they recommend one.
  • For foundation cracks that are wide, growing or uneven, ask whether a structural engineer should assess them first.
  • For mould, asbestos or radon, hire professionals qualified for that specific work, and don't disturb suspect materials yourself.
  • Get a written quote that lists excavation, membranes, weeping tile, sump pumps and restoration of landscaping or finishes.

Questions to ask foundation contractors before you hire

  • Where do you think the water is coming from, and how did you confirm it?
  • Do you recommend interior or exterior waterproofing for my home, and why?
  • Should a structural engineer look at these cracks or this wall?
  • Does this work need a permit from my municipality?
  • Is your warranty transferable if I sell the house, and what does it cover?
  • How will you restore the landscaping, driveway or basement finishes afterwards?
  • If you find mould or asbestos, how will it be handled and by whom?

When to call a pro for foundation repair

  • Water on the basement floor or damp walls after rain or snowmelt
  • Foundation cracks that are growing, or walls that bow or lean, which should be assessed by a qualified professional
  • Musty smells or mould that keeps coming back
  • Suspected asbestos in insulation, flooring or pipe wrap: leave it undisturbed and call a qualified abatement professional.

Foundation repair permits and local rules

Some foundation repair work needs a permit or has to meet local bylaws. Rules vary by municipality, so ask your pro whether a permit is needed and who will apply for it — and check with your city or town if you’re unsure.

Permits and licensing

Free project calculators

Ready to get foundation repair quotes?

Tell us about your foundation repair project.

Do you offer foundation repair services?

Join LokalMatch to get matched with homeowners in the areas you serve.