Melbourne’s Leading Concrete Pouring Specialists
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A concrete slab cost per m2 is a derived number, not a price. Concrete is supplied and charged by volume, so a square metre rate only exists once thickness, reinforcement, site classification and scope are fixed. That is why two defensible quotes for the same floor area can differ by a wide margin, and why any published cost of concrete slab per m2 in Australia should be treated as a starting question rather than a benchmark.
This article covers the rate itself: what one square metre of slab buys and which variables move it. For total project budgeting, see our guide to what a concrete slab costs in Australia. Urban Pour publishes no rates.
Concrete arrives on site measured in cubic metres. A batching plant sells volume. A slab, however, is described by the area it covers, so somewhere between the docket and the quote, a volume figure gets converted into an area figure. That conversion is entirely governed by thickness.
The arithmetic is simple enough to run yourself. A square metre of slab consumes a volume equal to its thickness expressed in metres. Increase the thickness and the volume per square metre rises in direct proportion, before you touch reinforcement, formwork or labour. A rate quoted without a stated thickness is therefore not comparable to anything.
Volume is the easy part. The variable that decides which row you are on is how thick the slab needs to be, and that is set by the engineer against loads and ground conditions, not chosen to hit a rate.
Three different numbers commonly get called the same thing. Supply-only is concrete delivered to the kerb. Supplied and placed adds the labour to get it in, screeded and levelled. Supplied, placed and finished adds the finish, and sometimes the curing and protection with it. A builder comparing a supply-only rate against a placed rate is comparing two unrelated numbers.
Ask for the rate broken into supply, placing, reinforcement, formwork and finish, with the exclusions written down. A subcontractor who prices this work every week can produce that split without difficulty. A rate that cannot be broken down is a rate that will be varied later.
Slab type sets the amount of formwork, steel, propping and engineering input a square metre needs. It moves the number further than any other single decision.
Suspended and post-tensioned slabs are the two that break rate-sheet thinking, because formwork and propping become a major share of the number rather than an incidental. For the pricing detail specific to stressed slabs, see post-tensioned slab pricing factors.
Thickness sets volume, and volume sets a floor under the rate. Reinforcement then sets much of what sits above that floor, through both material and labour.
Mesh is the fastest to fix and suits slabs where reinforcement is uniform. Bar takes longer, is scheduled and tied to a drawing, and carries far more labour per tonne. Fibre changes the crack-control behaviour of the mix rather than replacing structural steel, and is a specification decision rather than a substitution a builder makes to save money. Steel fixing labour is a separate cost from steel supply, and quotes that fold them together are difficult to compare.
Concrete strength grade works the same way. The grade is set by the engineer against exposure and structural demand. It is a specification input, not a lever to pull when a quote comes back high. If two rates differ and the grades differ, the rates were never comparable. Where a slab carries substantial steel, the scope belongs with a subcontractor who does reinforced concrete construction as core work rather than as an add-on.
For a rate to be comparable, the quote must state:
Two identical slabs on two Melbourne streets can price very differently, and site classification is usually why. AS 2870 sets the method for determining the classification of a site along with the design and construction requirements for slab on ground, stiffened raft, waffle slab, strip, pad and piled footings, as the Housing Industry Association sets out in its guidance on residential slabs and footings published in January 2022.
The classes run from stable through progressively more reactive ground, and are commonly written as:
Melbourne carries a great deal of reactive clay, which makes this a first-order variable rather than a footnote. Moving up the classes adds beam depth, steel and excavation, and it does so before any negotiation on rate occurs. Classification is determined by a geotechnical report and confirmed by the engineer, so a per square metre rate quoted before classification is provisional by definition. Treat it as an indication, and expect it to be restated once the report lands.
Nothing on a rate sheet reflects what a truck can actually reach. Access decides whether concrete is chuted directly, barrowed, or placed by pump, and pump requirements are usually the largest single access-driven cost on a suburban site. Boundary conditions on tight blocks, overhead services, and the standing position available for a boom all feed into it.
Fall across the slab area matters just as much. A site cut on a sloping block generates spoil, and spoil generates cartage. Where levels change across a footprint, benching is required to create workable platforms, and the volume of that work is set by the ground rather than the floor area. This is why site benching and excavation is priced on conditions rather than by square metre.
Excavation is also a regulated activity. The WorkSafe Victoria compliance code for excavation, published in December 2019, covers the duties attached to excavation work, how work is planned and organised, and how the risk of ground collapse is controlled. Those obligations are real work with real cost, which is why excavation is not a line to be haggled down against an area rate.
Answer these before asking anyone for a rate:
Formwork cost tracks edge length and complexity, not area. A long, narrow slab has far more perimeter per square metre than a square one of the same area, so it costs more per square metre even with identical concrete and steel. Set-downs, steps, rebates and returns each add setting-out time and stripping time.
Finish carries its own labour profile. A broom finish is quick. A steel trowel finish takes more passes and more time on site. Burnished and exposed aggregate finishes are separate trades of work again, with their own tolerances and their own risk of rework. Curing and protection are genuine costs, particularly on exposed pours, and construction joints add both setting out and detailing.
None of these appear in a headline rate, and all of them appear in the final invoice.
Construction prices move every quarter. The Australian Bureau of Statistics recorded in its Producer Price Indexes release for the June 2026 quarter that building construction prices rose 1.4% in the quarter, with house construction up 2.0%. A rate lifted from a cost guide, or from a quote issued two quarters ago, is a historical figure rather than a benchmark. Any rate worth comparing carries the date it was issued.
If two quotes answer all ten of those the same way and still differ, you are looking at a genuine commercial difference. If they answer them differently, you are not comparing rates at all.
There is no single honest national figure. A per square metre charge only becomes meaningful once thickness, reinforcement, concrete grade, slab type, site classification and scope inclusions are fixed, and it changes with site access and finish. Any rate offered without those variables stated is an average of unrelated jobs rather than a price for yours.
Concrete is sold by volume, and the supply rate is set by the batching plant against mix design, strength grade, additives, delivery distance and load size. Those rates move with input costs, so a cubic metre figure is only valid for a stated plant, mix and date. A supply rate also excludes placing, reinforcement, formwork and finishing.
No. A per square metre rate covers only the slab work it is defined to cover. A total slab cost includes everything around it, including excavation, spoil, services, engineering, inspections and any work outside the slab footprint. Multiplying a rate by floor area gives you a slab subtotal, not a project figure, and the two are routinely confused.
Directly. A square metre of slab consumes a volume equal to its thickness in metres, so a 150mm slab consumes half again as much concrete per square metre as a 100mm slab. Thickness also affects reinforcement and placing time. This is the main reason a rate quoted without a stated thickness cannot be compared to another.
Substantially. Classification under AS 2870 determines footing and slab design, and more reactive sites require deeper beams, more steel and more excavation. On Melbourne's reactive clay this is one of the largest variables in the whole rate. Classification comes from a geotechnical report, so any rate quoted beforehand is provisional.
Usually because they are pricing different scopes. One may be supply-only against another that is supplied, placed and finished. Thickness, grade, reinforcement, pump allowance, spoil cartage and finish can all differ. Line the two up against the same specification and the gap generally turns out to be scope rather than margin.
A per square metre figure is only as good as the specification behind it. Fix the thickness, the reinforcement, the grade, the classification and the inclusions, and the rate stops being a guess and starts being something you can hold a subcontractor to. Urban Pour is the structural concrete subcontractor whose rate sits inside a builder's quote in Melbourne. Send through your drawings and site details and talk to us about your slab.
How waffle pod and stiffened raft slabs differ on site, and what decides which one your engineer specifies.
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The footing types used under Australian slabs, what sets their depth, and the standards that govern the design.
See moreA builder's guide to what actually sets the concrete slab rate per m2, from slab type to site classification.
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