Cost Guides
Concrete Slab Cost QLD: Shed, Garage & House Slabs (2026)
By Fraser Coast Concreting · 20 June 2026
Quick answer
As a guide, a plain concrete slab in Queensland typically costs $80–$120/m² supplied and laid. A common 6x6m (36m²) shed slab usually runs about $2,900–$4,300, and a 6x9m (54m²) slab around $4,300–$6,500. Thickness, reinforcement, site prep and soil type all change the price. A written quote is the only accurate figure.
Whether it’s a slab for a new shed, a garage or a house extension, the price comes down to a handful of factors: size, thickness, reinforcement, site prep and soil. This guide gives you realistic 2026 ranges for Queensland, with a table of common shed slab sizes so you can budget quickly.
These are indicative figures, presented as typical ranges. The only accurate price is a written quote based on your actual site.
Concrete slab cost per m² in QLD
For a standard plain slab, expect roughly $80–$120/m² supplied and laid in 2026. Where you sit in that range depends mostly on thickness, the reinforcement specified and how much site preparation is needed.
A domestic slab is commonly 100mm thick with steel mesh. Slabs that carry vehicles, machinery or heavy storage are often poured thicker (125mm or more) with heavier reinforcement, which lifts the per-m² cost.
Shed slab cost by size
Here are indicative totals for common shed slab sizes at the typical $80–$120/m² range. Use these to get a rough budget before you call for a quote.
| Shed size | Area | Indicative cost (plain slab) |
|---|---|---|
| 6 x 6 m | 36 m² | $2,900 – $4,300 |
| 6 x 7 m | 42 m² | $3,400 – $5,000 |
| 7 x 7 m | 49 m² | $3,900 – $5,900 |
| 6 x 9 m | 54 m² | $4,300 – $6,500 |
| 7 x 9 m | 63 m² | $5,000 – $7,600 |
| 9 x 9 m | 81 m² | $6,500 – $9,700 |
As a guide only. Bigger slabs often cost a little less per m² because fixed costs are spread further, while small slabs can cost slightly more per m².
House and garage slabs
House and garage slabs are usually engineered to a structural plan, with footings, thickened edges and reinforcement designed for the building and the soil. Because of the engineering, formwork and extra concrete in the beams, they generally cost more per m² than a simple shed slab. These jobs are best quoted from the engineer’s plans rather than a rule of thumb.
What changes the cost of a slab
- Thickness. A 100mm domestic slab is the baseline. Thicker pours for sheds, garages, sheds storing vehicles or workshops use more concrete and cost more.
- Reinforcement. Steel mesh is standard; heavier mesh or added bar increases strength and price.
- Site preparation. Clearing, levelling, importing and compacting road base, and setting formwork all add to the cost. Sloping or uneven ground costs more to prepare.
- Fall and finish. Slabs often need a slight fall for drainage, and a particular finish (trowel, broom) affects labour.
- Footings and edge beams. Sheds and buildings usually need thickened edges or footings, which add concrete and steel.
- Reactive (clay) soil. Much of the Fraser Coast and Maryborough sits on reactive clay that swells and shrinks with moisture. Slabs on reactive soil often need stronger engineering to resist movement and cracking, which adds cost but is well worth it.
Why soil matters on the Fraser Coast
Reactive clay is common around Maryborough and parts of Hervey Bay. When it gets wet it expands, and when it dries out it contracts, and that movement can crack an under-built slab. A properly engineered slab with the right footings, reinforcement and base preparation is the best insurance against this. It’s one of the main reasons we don’t recommend cutting corners on prep.
What’s actually included in a slab price?
When you see a per-m² figure, it helps to understand what that number is paying for. A typical supplied-and-laid slab price rolls together several stages of work:
- Set-out and excavation. Pegging the slab to the right level and digging out topsoil so the slab sits on a stable, compacted base rather than soft ground.
- Base preparation. Importing and compacting road base or crusher dust to create an even, free-draining foundation. This is the layer most cowboys skimp on.
- Formwork. Setting the timber or steel forms that hold the wet concrete to the right shape, level and fall.
- Reinforcement. Laying steel mesh (and bar in footings or edge beams) on bar chairs so the steel sits in the correct position within the slab.
- The concrete itself. Supply and delivery of the right mix strength (commonly 20–32 MPa depending on the job), plus pump hire where access is tight.
- Placing, screeding and finishing. Pouring, levelling, and finishing the surface to the agreed finish (broom, trowel or otherwise).
- Curing and clean-up. Keeping the slab moist as it sets, stripping forms and removing waste.
When two quotes look different, the gap is almost always in the base prep, the reinforcement spec or the concrete strength, not the finishing.
Worked example: budgeting for a 6x9m shed slab
Say you’re putting in a 6 x 9 m (54 m²) slab for a Colorbond shed at Hervey Bay on reasonably level ground.
- At the plain slab rate of $80–$120/m², the slab itself sits around $4,300–$6,500 as a guide.
- If the shed will store a caravan or a vehicle hoist, the engineer may call for a thicker pour and heavier reinforcement, which nudges you toward the upper end or beyond.
- If the block slopes or has soft fill, extra excavation and imported base could add several hundred dollars before a drop of concrete is poured.
- On reactive clay, thickened edge beams and stronger steel are money well spent and will lift the figure again.
The point is that the headline per-m² rate is a starting point. The site decides where you actually land, which is why a written quote after a site visit is the only number you can rely on.
How slab thickness changes the cost
Thickness is one of the biggest levers on price because concrete is sold by volume.
| Slab thickness | Typical use | Effect on cost |
|---|---|---|
| 100 mm | Standard domestic slab, garden sheds, paths | Baseline |
| 125 mm | Larger sheds, light vehicle storage | Moderately higher (more concrete + steel) |
| 150 mm+ | Workshops, machinery, heavy vehicles | Highest (engineered, more concrete and reinforcement) |
Going from 100 mm to 150 mm adds roughly 50% more concrete to the same footprint, so it’s a real cost, but it’s the right call when the slab has to carry weight.
Does a bigger slab cost less per m²?
Generally, yes. Many of the costs on a slab job are fixed regardless of size: getting the crew and gear to site, hiring a pump, setting up forms and mobilising the finishing team. When those fixed costs are spread across more square metres, the per-m² rate tends to ease. That’s why a small 3 x 3 m slab can feel expensive per metre, while a 9 x 9 m slab is more efficient. If you’re planning a shed, it’s often worth sizing the slab once for what you’ll eventually need rather than pouring twice.
Should you pour a slab in the wet season?
Concreting is possible year-round on the Fraser Coast, but timing matters. Heavy wet-season rain can wash out a freshly poured surface and saturate the base before the pour, making compaction harder. A good concreter will plan the pour around the forecast and the tides for low-lying coastal blocks. If your project isn’t urgent, the drier months often give the cleanest run, though a well-organised crew can work around the weather in most conditions.
How to compare slab quotes
Make sure each quote states:
- Slab thickness and reinforcement type
- Concrete strength (MPa) being supplied
- Site preparation and base material included
- Footings or edge beams where required
- Whether the slab is engineered for your soil
- Site clean-up and rubbish removal
If a quote is vague on any of these, ask. A clear, itemised quote is a sign of a concreter who plans the job properly, and it makes comparing prices genuinely fair.
Common slab types and what they’re used for
Not every slab is the same, and the type you need affects both the engineering and the price.
- Slab-on-ground (raft slab). The most common domestic slab, where the floor and footings are poured together as one stiff raft. Ideal for sheds, garages, granny flats and houses on reactive soils because it moves as a single unit.
- Strip footing with infill. Perimeter footings carry the walls, with a separate floor slab inside. Sometimes used on firmer ground.
- Waffle slab. A raft slab formed over void formers, popular for new homes on reactive clay because it’s stiff and uses concrete efficiently.
- Simple shed or path slab. A straightforward 100 mm reinforced slab for light-duty use where heavy engineering isn’t required.
For most Fraser Coast shed and garage jobs, a properly reinforced slab-on-ground does the job. House slabs and anything carrying serious load should follow an engineer’s design.
How long does a slab take to pour and cure?
Pouring itself is usually quick, often a single day for a domestic slab, but the work either side is where the time goes. Site prep, forming and steel-fixing can take a few days depending on the job and the ground. After the pour, concrete needs time to cure: you can generally walk on it within a day or so, but it keeps gaining strength for weeks. As a rule of thumb, light foot traffic is fine after a couple of days, and you’d wait longer before putting heavy loads or a shed build on top. Your concreter will advise the right timeframes for your specific slab and the weather at the time.
Can I save money on a slab without cutting corners?
There are sensible ways to keep costs down that don’t compromise the result:
- Get the site ready. Clearing vegetation and rough-levelling yourself (where safe) can reduce prep labour.
- Good access. Clearing a path for the truck or pump saves time and pumping costs.
- Pour once, sized right. Building the slab to suit your future plans avoids a second job later.
- Bundle work. Combining a slab with other concreting on the same visit can spread the fixed mobilisation costs.
What you should never trim is base prep, reinforcement, concrete strength or curing. Those are the things that keep the slab sound on our reactive soils for decades.
Related guides
- How much does a concrete driveway cost in QLD?
- Why is my concrete driveway cracking?
- Explore our concrete slabs service for sheds, garages and extensions.
Get an accurate slab quote
The ranges above are great for budgeting, but every slab depends on your site and soil. Fraser Coast Concreting provides free written quotes for concrete slabs across Hervey Bay, Maryborough, Rainbow Beach and Tin Can Bay. Get your free quote here and we’ll give you a clear, itemised price for your shed, garage or house slab.