Concrete Levelling and Slab Jacking WA 2026 - Get Free Quotes

Why the Technique Suits Perth Conditions

Slab levelling addresses one specific problem, which is a slab that has lost the support beneath it. It does nothing for cracked concrete, nothing for a slab that was too thin, and nothing for reinforcement corrosion. What it does is fill the space under a slab and put it back where it belongs, and whether that is the right treatment depends entirely on why the slab moved. Getting that question right is most of the value in the assessment. Settle that question before drilling begins.

In much of Australia slabs move because reactive clay swells and shrinks with moisture, lifting and dropping through the seasons. Injecting material under a slab sitting on clay that is still moving treats a symptom, since the clay will move again next season and the slab will follow it. That is no criticism of the technique, simply a mismatch between the technique and the ground.

The Swan Coastal Plain does something different. Sand is not reactive, so it does not swell or shrink with moisture, and a slab on well compacted sand sits on a stable base. What sand does is wash out when water runs through it, leaving a genuine void with nothing supporting the concrete above. The sand that is left is perfectly capable of bearing load, and there is simply less of it where the water went. Note the measurement while you are there.

That is a void problem, and filling voids is precisely what this technique does. It is why slab jacking performs so reliably across Perth and why the outcomes here tend to be better than the same technique applied on a reactive site in Melbourne or Adelaide. The method matches the failure mode. Owners moving here from the eastern states are frequently surprised by how well it performs. Include that when you first make contact.

Perth Hills properties sit outside that generalisation. Ground conditions east of the plain include clay and laterite, a reddish iron rich soil common through the hills, and a slab moving on reactive clay in Kalamunda or Mundaring needs a different assessment before injection is considered. A contractor who treats every Western Australian slab as a sand problem has not looked at the site. Find out which conditions they believe apply to your block. It should appear in the written scope.

The practical consequence for an owner is that the first question is not how much a lift costs. It is whether the slab has lost support or whether something is still moving, because only one of those is a candidate for this work. The assessment answers that question and it is inexpensive relative to the work itself.

How Slab Jacking Actually Works

The process starts with measurement. Levels are taken across the slab and the surrounding surfaces to establish how far it has dropped and what the target level should be, since lifting to the wrong height creates its own problems where a slab meets a threshold, a step or an adjoining surface. Agreeing the target level before anything is drilled prevents that entirely.

Small holes are then drilled through the slab in a pattern determined by the size of the area and where the void sits. On a driveway or patio those holes are typically the diameter of a pencil to a finger, spaced across the affected area, and a full lift on a modest driveway might involve a few dozen of them. Spacing depends on the slab, the extent of the void and how the material needs to travel underneath.

Injection follows. A two part polyurethane resin is pumped through each hole under controlled pressure, and it expands as it cures, first filling the void and then, once the void is full, beginning to lift the slab. The expansion does the work, with no mechanical jack involved, which is why the technique reaches places no equipment could. There is no excavation and nothing has to be lifted from the edges. Raise it at the assessment.

Monitoring is what separates a good operator from a poor one. The lift is measured continuously with a laser level or a digital indicator while the resin goes in, and material is delivered in small increments across multiple points so the slab rises evenly. Lifting too fast at one point cracks the slab, which is the main risk in the whole process. A patient operator working across many points is doing the job properly. Watch for whether the level is actually being measured while material goes in.

Cure time is the practical advantage. The resin reaches most of its strength within minutes, so a driveway lifted in the morning carries a car that afternoon, and a warehouse floor can go back into service the same shift. The holes are patched flush and remain faintly visible on close inspection. On plain grey concrete they blend within a few months of weathering. Have it written into the quote. What is agreed verbally on site tends to be remembered differently later.

On a habitable house slab the process is the same and the stakes are higher, so a level survey, engineering input and a clear understanding of what caused the settlement should all come before injection. Where structural questions arise, that overlaps with underpinning services, which addresses footings. They are different problems with different solutions and the distinction matters.

Polyurethane Injection or Cementitious Mudjacking

Two methods exist and the difference carries more weight in Perth than in most places. Traditional mudjacking, the older of the two methods, pumps a cementitious slurry, essentially a sand, cement and water mixture, through larger holes to fill the void and raise the slab. Polyurethane injection uses an expanding two part resin through much smaller holes. Both fill voids and both can lift a slab, and they behave very differently in the ground. Take dated photographs and hold on to them. They are worth keeping if the slab moves again.

Weight is the reason the distinction matters here. A cementitious slurry is heavy, and pumping a substantial volume of heavy material into a void in weak sand adds load to the very ground that failed to support the slab. On a sand site that additional mass can drive further settlement, which is the opposite of the intended result. It is a real consideration rather than a marketing argument between the two methods. Settle it before anything is drilled. Scope that shifts once injection has started gets expensive quickly.

Polyurethane weighs a small fraction of the same volume of slurry. It fills the void, provides bearing and adds very little load, and on the Swan Coastal Plain that difference is not a marketing point and a genuine engineering advantage. It is the main reason polyurethane has largely displaced mudjacking for residential work in Perth. The material cost is higher and the outcome on sand is generally better. Raise it with the contractor face to face. A specialist will answer without hesitation.

Hole size and finish follow from the method. Mudjacking requires holes large enough to pump slurry, commonly around forty millimetres, which leaves obvious patches. Polyurethane holes are far smaller and patch far less visibly, which matters considerably on liquid limestone, exposed aggregate or any decorative finish. On a decorative driveway the difference in finished appearance is obvious.

Water resistance is the last difference. Cured polyurethane is unaffected by water, so a void that refills with moisture does not degrade the material, whereas a cementitious fill in a location that keeps getting wet is less durable. On a site where the water source cannot be fully eliminated, that matters. Some sites cannot be made completely dry and the material choice should reflect that.

Mudjacking still has a place on large commercial slabs and in situations where bulk fill at low cost is the priority. For a residential driveway, patio or garage on sand, polyurethane is generally the better fit, and a contractor should be able to explain which they use and why. An operator who cannot articulate the difference is not the specialist you want.

Finding the Water Before Lifting Anything

This is the step that determines whether the work lasts and it is the one most often skipped. A void in sand was created by water moving through it, so injecting resin into that void without stopping the water means the water simply carries away sand somewhere adjacent and a new void forms beside the repair. Owners then conclude the levelling failed when the water was never addressed.

Leaking reticulation is the first suspect on any Perth block. Retic lines run beside and under driveways, paths and patios, and a cracked poly line or a solenoid valve passing water continuously excavates sand without showing anything on the surface, since the water soaks straight down instead of pooling. Checking the system through irrigation and garden watering systems is cheap relative to the slab work. Focus on the zones and valve boxes nearest the affected slab first.

Stormwater is the second. Perth soaks roof water away through soakwells rather than piping it to a street drain, so a soakwell that has silted up, collapsed or was undersized for an extended roof area discharges into the sand beside the slab every time it rains heavily. Capacity work sits with soakwell installation and connection work with stormwater drainage plumbing. Undersizing is more common than outright failure, because patios and carports add roof area without anyone revisiting the drainage.

Under slab plumbing is the third and the most serious. A leaking water service or a failed drainage line beneath a house slab washes sand out from directly under the building, and that produces settlement that is structural. Locating it before any injection is essential, since resin injected over an active leak seals nothing and fixes nothing. Under slab plumbing problems are also the ones most likely to involve insurance, so establishing the cause matters for more than the repair.

Detection is straightforward and worth paying for. Acoustic listening, pressure testing and thermal methods used in water leak detection identify concealed leaks without opening anything speculatively, and any competent slab levelling contractor will want that answered before quoting a lift. If nobody asks about water, that tells you something about the operator.

Western Australia offers a useful seasonal cross check that other states do not. With scheme water users on a sprinkler roster and a winter sprinkler ban applying through the cooler months, settlement continuing during the ban points at stormwater or plumbing rather than reticulation, and settlement worsening through summer points back at the retic. That is a genuinely useful piece of local logic and it costs nothing to apply.

Void Filling Against Lifting

These are two different jobs and they are priced differently, so understanding which one you need avoids paying for the wrong thing. Void filling injects material to fill the space and restore bearing without attempting to move the slab, and it suits a slab that has lost support but is still at an acceptable level. It is the cheaper of the two options and it is frequently all that is needed.

That situation is more common than owners expect. A slab can be perfectly level and completely unsupported across part of its area, and the only symptom is a hollow sound when tapped or a slight movement underfoot. Filling the void at that stage prevents the settlement that would otherwise follow. Catching it before the slab drops is considerably cheaper than lifting it afterwards.

Lifting is the more involved version and it carries more risk. Raising a slab that has dropped means overcoming its weight and any friction at its edges, and doing it evenly enough that the slab does not crack. That is why lifts are done in small increments across many points with continuous measurement. The slab is heavier than it looks and the forces involved are substantial.

Full recovery is not always achievable and a straight contractor will say so before starting. A slab that has settled unevenly, that is keyed into adjoining surfaces or that has already cracked may lift most of the way rather than all of it, and agreeing what a successful outcome looks like before work begins prevents disappointment afterwards. Get the expected result stated in writing.

Where a slab cannot be lifted acceptably, grinding a step down or resurfacing to a new level is sometimes the better answer, and comparative pricing sits under concrete resurfacing cost. Interior floor levelling by screeding is a different technique again, covered under floor levelling and screeding. That one adds material on top rather than lifting from beneath.

Where Slab Jacking Is Used

Driveways are the most common residential application and the settlement is usually near the garage, at the crossover end or along an edge where a garden bed or lawn sits. Lifting a driveway avoids the colour and texture mismatch that section replacement always produces, which matters particularly on decorative finishes. It is also considerably faster, which matters on a single driveway property.

Paths and steps are the smallest and often the most urgent. A step that has formed at a joint in a path is a genuine trip hazard, and on a rental or a strata property it is a liability issue rather than a cosmetic one. These are quick jobs and they are frequently the cheapest way to remove a risk. On a rental or a strata property that risk carries liability with it.

Patios, alfrescos and pool surrounds sit in between. Perth has a very high proportion of properties with an outdoor entertaining area on a slab, and settlement there produces ponding, uneven furniture and water running the wrong way. Where the surround is part of a pool area, related work sits with concrete pool surrounds. Ponding around a pool also creates a slip hazard, so the level correction does two jobs.

Garage and shed slabs settle for the same reasons and carry heavier loads, so a void under a garage slab shows up quickly once a vehicle is parked on it. These slabs are frequently thinner and less reinforced than a house slab, which makes even lifting more important and makes over lifting easier to do. An operator experienced with garage slabs will approach one differently from a driveway.

House slabs are the highest stakes application. Settlement under part of a habitable slab produces cracking in walls, doors that stick and floors that slope, and while injection can restore support the cause needs establishing first. Structural questions belong with an engineer, and a general condition picture through a building inspection is a reasonable starting point. Wall cracking above a settled slab area is worth photographing and dating before any work.

Commercial and industrial floors round it out. Warehouse slabs across the Perth industrial areas settle at joints and around racking, and the ability to lift a floor overnight without demolishing it is worth a great deal to an operating business. Pricing there works per square metre and depends heavily on access and operating hours. Out of hours work costs more and it frequently saves more than it costs in avoided downtime.

When Slab Jacking Will Not Work

A slab broken into multiple pieces is not a candidate. Lifting relies on the slab acting as a unit, so a slab that has fractured into several sections will lift unevenly, hinge at the cracks and end up worse than it started. Replacement is the answer in that situation. A good operator will tell you at the assessment.

A slab that is too thin or too lightly reinforced for its span presents the same problem. Some older paths and shed slabs were poured thin, and applying lifting force to them cracks them, which is why an experienced operator will assess thickness before committing to a lift. Core samples or a simple depth check settle the question quickly.

Active movement rules it out until the cause is fixed. Reactive clay heave in the hills, an unrepaired plumbing leak, or ongoing erosion from a stormwater problem will all move the slab again after the lift, so injection into a moving situation is money spent on a temporary result. Fix the cause and then reassess whether a lift is still needed.

Structural damage to the concrete is outside the scope entirely. Injection restores support and does nothing for corroded reinforcement, spalling edges or structural cracking, and those need remedial concrete work through concrete repair and crack repair instead of or alongside a lift. Sometimes both are required, and sequencing them correctly saves doing the access twice.

Very large settlements are a judgement call. Lifting a slab a modest amount is routine and lifting one a great deal introduces more risk of cracking and requires far more material, so at some point replacement becomes the more sensible option. A contractor who will not lift a badly settled slab is giving you honest advice. Take that opinion seriously rather than shopping for someone who will.

Comparing Levelling Against Replacement

Cost is the obvious comparison and it is not the only one. Section replacement runs higher per square metre than a lift on most residential jobs, and the gap widens once you account for breaking out, disposal of the old concrete and reinstating the surrounding area. Removal work alone sits with concrete demolition and site preparation. Disposal is a real line item and it should appear in any replacement quote.

Time is where the difference is starkest. A lift takes hours and the slab carries traffic the same day, while a replacement takes days to pour and far longer before a vehicle should drive on it. For a household with no verge parking or a business that cannot close a loading area, that difference decides it. Time out of service is frequently worth more than the price gap.

Appearance favours lifting on any decorative finish. New concrete never matches concrete that has weathered for fifteen years, and on liquid limestone or exposed aggregate the mismatch is pronounced, since the colour, the stone and the exposure depth all differ. Comparative pricing on those finishes sits under liquid limestone cost and exposed aggregate concrete cost. Knowing what a replacement would cost helps you judge whether a lift represents value.

Replacement wins where the concrete itself has failed. A slab that is cracked through, spalling at the edges, too thin for its use or simply at the end of its life is not worth lifting, and putting money into levelling it defers a replacement that is coming anyway. New work sits with concreting services. Putting money into levelling a slab at the end of its life defers a cost.

Replacement also wins where levels need to change substantially or where the base itself needs rebuilding. If a driveway needs regrading to fix drainage, or if the base was never properly compacted across the whole area, starting again with correct preparation is the durable answer. Comparative pricing sits under concrete driveway cost and concrete slab cost. Regrading for drainage is a legitimate reason to start again.

The sensible approach is to price both where the choice is genuinely open. Contractors tend to recommend the method they are equipped for, which is understandable, and getting one quote from a levelling specialist and one from a concreter gives you the real comparison. Two quotes using different methods is more informative than two using the same one.

Registration, Contracts and Site Safety

Where residential building work exceeds twenty thousand dollars a registered building contractor is generally required in Western Australia, with home indemnity insurance required above that threshold. Many slab levelling jobs sit below it, and a large residential lift or a commercial floor may not, so it is a question to ask before assuming. The answer changes what protections apply to the contract.

Registration is administered by Building and Energy, which sits within the Department of Energy, Mines, Industry Regulation and Safety and also takes building work complaints in Western Australia. That is a different regulator from the eastern states, and general state information is published by the Western Australian Government. Registration can be confirmed before signing anything.

Residential building contracts within defined value ranges fall under the Home Building Contracts Act 1991, which requires them to be written and caps what can be taken as a deposit, and legislation is published on the Western Australian Legislation site. Read the deposit provisions before paying anything upfront on a job of any size. The limits exist for a reason and it is worth knowing what they are.

Consumer guarantees apply to the service regardless of value, requiring work to be carried out with due care and skill and to be reasonably fit for purpose, and guidance is published by the Australian Competition and Consumer Commission. Those rights sit alongside whatever warranty the contractor offers. They cannot be excluded by a contract term.

There are obligations attaching to how the work is carried out. Drilling concrete generates respirable crystalline silica dust requiring water suppression or on tool extraction, injection is carried out under pressure with two part chemical products that require appropriate handling and ventilation, and requirements are published by WorkSafe WA and nationally by Safe Work Australia. A crew drilling dry in a visible dust cloud is telling you how the rest of the job will be run. Drilling concrete releases silica dust, and suppression or extraction is required rather than optional.

Find out what warranty attaches to the work and what it actually covers. A reputable operator will warrant the lift and the material for a defined period, and no operator can warrant against future settlement caused by a water source nobody fixed, which is another reason the cause should be dealt with first. A warranty that excludes settlement from an unfixed water source is a reasonable exclusion.

Strata Schemes, Rentals and Commercial Property

In a Western Australian strata scheme, driveways, paths and common accessways are frequently common property, making settlement a strata company responsibility. Western Australia has strata companies operating under the Strata Titles Act 1985, and the strata plan determines where the boundary falls. Check it before arranging anything, since unauthorised work on common property creates its own problems.

Shared accessways are where this bites hardest. A settled section of a shared driveway affects every lot using it, the cost is shared according to the scheme, and getting a proper assessment before going to tender matters more than on a single dwelling because the quotes will otherwise describe different jobs. An independent assessment produces the specification that makes them comparable.

Levelling is often attractive to a strata council for a practical reason beyond cost. A shared driveway cannot be closed for a week while concrete cures without seriously inconveniencing residents, and a technique that returns the surface to service the same day removes that problem entirely. For a scheme with limited alternative access that can be the deciding factor.

For rental properties the lessor is responsible for maintaining the premises, and a step in a path or a settled slab is a trip hazard, not a cosmetic issue. Tenants should report it in writing with photographs, noting the height of any step, since that detail establishes the severity. Photograph it with a ruler in the shot so the measurement is on record.

Commercial and industrial property adds an operational dimension. Warehouse floors settle around racking legs and at joints where forklift traffic concentrates, and uneven floors damage equipment and create safety problems. The ability to lift overnight or across a weekend is worth more to an operating business than the cost difference against replacement. Racking may need to be moved or partially unloaded, so plan the sequence with the contractor.

What to Look Out For

Start with the water question. A quote to lift a slab with no discussion of why it settled is a quote for a temporary result, because on Perth sand something moved the base and it will do it again. Ask what the operator thinks caused it and what they are basing that on. An operator who cannot name a cause has not assessed the site.

Be cautious of anyone lifting without measuring. The lift should be monitored continuously with a laser level or digital indicator and delivered in small increments across many points, and an operator working by eye is how slabs crack during the process. Confirm how the lift will be measured. A laser level and a written record of the achieved lift is a reasonable expectation.

Watch for cementitious mudjacking proposed on a residential sand site without explanation. It is a legitimate technique in the right situation, and the weight of the material on weak sand is a genuine consideration, so a contractor should be able to say why it suits your site if they are recommending it. There are legitimate reasons and you should hear one.

Check the realistic outcome is agreed before work starts. Full recovery is not always achievable on a slab that has settled unevenly or is keyed into adjoining surfaces, and agreeing what success looks like beforehand prevents an argument about the result afterwards. Put the expected outcome in the scope.

Finally, be sceptical of a lift proposed on a badly cracked slab. Lifting relies on the slab acting as a single unit, so a slab in several pieces will hinge at the cracks and finish worse than it started. A contractor declining to lift that slab is giving you good advice. Getting a second opinion is sensible and shopping until someone agrees is not.

How to Get Useful Quotes

Give the area and the drop. Approximate dimensions in metres, how far the slab has settled at its lowest point measured against the adjoining surface, and whether the settlement is even across the area or concentrated at one edge. A tape measure and five minutes produces all of it. Measure from a straight edge laid across the settled area to the adjoining surface.

Say what the slab is and what it carries. Driveway, path, patio, alfresco, garage, house slab or commercial floor, the finish involved, roughly how old it is, and what drives or walks on it. Vehicle loading changes both the assessment and the specification. Mention caravans, boats or heavy vehicles specifically.

Describe the water history, since on a Perth block that is the diagnostic that matters. Where the soakwells are and whether they surcharge in winter, whether retic runs near or under the slab, whether there is a valve box nearby, and whether anything has been dug up or built recently. Work done near a slab in the year before it settled is frequently the explanation.

Photograph it usefully. A wide shot of the whole area, a low angle shot along the surface where the drop shows clearly, close ups of any cracking, and a photograph showing the step where the settled slab meets an adjoining surface. Place a ruler in the step shot so the drop is measurable. A short video during heavy rain showing where water runs is worth more than any still image.

Have each quote state what caused the settlement and how that was established, which material and method is proposed and why, whether void filling or a lift is being priced, how the lift will be monitored, what recovery is realistically expected, and what warranty applies and what it excludes. Six clear answers make two quotes genuinely comparable. A price per square metre with nothing behind it cannot be compared with anything.

Keeping the Void From Coming Back

Everything on this page comes back to keeping water out of the sand beneath your slabs, and the measures are ordinary maintenance. Soakwells sized for the actual roof area, cleared of silt and functioning, are the single largest factor on most Perth properties. Stand outside during the next heavy downpour and watch where the water actually goes.

Reticulation deserves an annual look. Checking for zones that run longer than programmed, valve boxes holding water, unexplained increases in consumption and damp patches appearing on hard surfaces catches most leaks while they are still small. It costs nothing beyond attention. A retic system running when it should not be is the most common finding.

Surface drainage matters as much as what happens underground. A slab that ponds water, a downpipe discharging beside a driveway edge, or ground falling toward a slab rather than away all concentrate water exactly where it does damage, and correcting falls is usually inexpensive. Broader site drainage sits under drainage, and persistent subsurface water under French drain and subsoil drainage installation. Correcting a fall away from a slab is usually a small job with a large effect.

Joints and cracks are the entry points on the slab itself. Sealing control joints and any crack that has opened keeps surface water from running straight into the base, and it is genuinely cheap preventive work compared with dealing with the void it would otherwise create. Resealing every few years is the cheapest item on this page.

Where landscaping or excavation work is planned near a slab, raise it with the contractor beforehand. Machinery, trenching and changes to ground levels all affect what happens under adjacent concrete, and that work sits with excavation and earthmoving or landscaping depending on the scope. Getting the sequence right prevents undoing a repair you have just paid for. Mention any planned works when getting a levelling quote.