How much does a 6 x 6 m shed slab cost in Australia in 2026?

A 36 m² shed slab with a plain broom finish typically costs between $2,500 and $5,000 supplied and poured, depending on excavation required, ground conditions and your location. Minimum job fees of $1,500 to $2,000 apply with most concreters, so small slabs rarely come cheaper than that regardless of size. Get a written quote for your specific site.

What is the average cost of a concrete house slab?

A full residential house slab in Australia commonly costs $80 to $130 per m² for a standard engineer-designed slab with mesh and reinforcement. On a 200 m² footprint that is roughly $16,000 to $26,000 or more. Complex sites, reactive soils and additional engineering requirements can push costs higher. Always get a site-specific quote, and confirm whether the price includes the engineering report, excavation and any required drainage.

Is a concrete slab cheaper if I supply the concrete myself?

Generally no, and most concreters will not work this way. Concrete must be ordered at the right grade, in the right volume, and delivered timed precisely to the pour. A licensed concreter takes responsibility for the mix specification, delivery timing and quality. If the concrete is wrong, that responsibility matters. Owner-supply arrangements can also void workmanship warranties.

Do I need an engineer for a shed or garage slab?

For a basic shed on flat, stable ground, engineering is often not required. For a house slab, it is almost always mandatory under AS 2870 and your local council's building approval conditions. In reactive soil areas (which cover large parts of Melbourne, Adelaide and Brisbane), even a garage slab may benefit from an engineer's input. Check with your local council and your concreter before assuming you can skip this step.

How long does a concrete slab take to pour and cure?

Pouring a standard garage or shed slab takes four to eight hours on the day, including finishing. The slab can typically be walked on within 24 to 48 hours. However, concrete reaches most of its design strength at 28 days. Avoid placing heavy loads, vehicles or structural walls on a new slab for at least seven days, and ideally longer in cold or dry conditions.

What concrete thickness do I need for a garage slab?

Most domestic garages are poured at 100 mm to 125 mm thick with SL82 or SL92 mesh reinforcement. If you plan to store heavy vehicles, a boat on a trailer or workshop equipment over about two tonnes, discuss a 125 to 150 mm slab with your concreter. Thicker slabs cost more in concrete volume but significantly improve long-term load performance.

Can I pour a concrete slab on an existing old slab?

Yes, in some circumstances. An overlay or bonded slab can work if the existing slab is sound, flat and properly prepared. It is not always cheaper than starting fresh once you factor in surface grinding and bonding agents. Your concreter should assess the existing slab for cracking, movement or contamination before recommending this approach.

Concrete Slab Cost Guide 2026 | Shed, House & Garage

Concrete Slab Prices at a Glance (2026)

Most Australian concreters charge $65 to $110 per m² for a standard reinforced concrete slab, supplied and laid. A typical 6 x 6 m shed slab (36 m²) runs $3,000 to $5,500 all in. A full house slab (150 to 250 m²) commonly lands between $15,000 and $35,000 or more, depending on engineering, site conditions and state. These are starting-point figures. A written quote from a licensed concreter is the only reliable number for your job.

Slab prices shift a lot depending on what the slab is for. A basic shed slab needs far less reinforcement than a footing-integrated house slab subject to structural engineering. Understanding what drives those differences helps you read quotes more critically, and spot ones that look too cheap to be complete.

Prices quoted throughout this guide are general market ranges sourced from Australian concreting businesses in 2026. Actual costs vary by site, council requirements, ground conditions and the contractor's workload in your area.

Slab Costs by Type: Shed, Garage and House

The biggest variable in slab pricing is what the slab has to do structurally. A garden shed slab carries very little load. A house slab must comply with AS 2870 (residential slabs and footings) and typically involves an engineer's specification, thickened edge beams, slab penetrations and sometimes a vapour barrier. Those extra steps cost money.

Slab Type	Typical Size	Price Range per m²	Typical Total Range
Small shed slab (plain/broom)	20 to 40 m²	$65 to $90	$1,500 to $4,000
Garage slab (reinforced, broom or trowel)	36 to 60 m²	$80 to $110	$3,500 to $7,500
House slab (engineer-designed, mesh + reo)	120 to 300 m²	$80 to $130+	$12,000 to $40,000+
Workshop / commercial slab (heavy-duty)	50 to 200 m²	$90 to $130	$5,000 to $28,000
Alfresco / entertainment slab	15 to 40 m²	$80 to $150	$1,500 to $7,500

House slabs almost always sit at the higher end because they include thickened perimeter beams, internal footings under load-bearing walls, and a geotechnical or engineering report in reactive-soil areas. That report alone can add $500 to $1,500 to the project before a single barrow of concrete is poured.

If you are building a shed or garage and want to avoid a minimum call-out fee, consider staging the job. Ask a concreter whether they have nearby pours scheduled. Piggy-backing onto a larger pour in your suburb can save you $500 to $1,000 on the minimum job fee.

Finish Options and What They Add to the Price

Plain broom finish is the cheapest practical surface for a shed or garage. It cures non-slip and needs no ongoing treatment. Once you move into exposed aggregate, stencil or a polished interior slab, the price per square metre climbs, and so do the skill requirements.

Finish	Approximate Price per m²	Common Uses
Broom finish (plain)	$65 to $90	Sheds, driveways, paths
Steel-trowel finish	$75 to $95	Garages, workshops
Exposed aggregate	$100 to $150	Outdoor entertaining, driveways
Coloured / stencilled / stamped	$100 to $150	Patios, pool surrounds, feature areas
Polished concrete (grind and polish)	$80 to $150	Interior floors, mancaves, commercial

Polished concrete has a wide range because the final finish level, number of grinding passes, densifier and sealer all vary. A basic salt-and-pepper grind sits near $80 per m². A high-gloss, fully processed interior floor can reach $150 per m² or beyond, particularly if the slab needs grinding flat first.

Stencil and stamp work depends heavily on pattern complexity, colour quantity and whether a release agent is used. Always ask for photos of completed jobs and check the sealer included in the quote, because re-sealing every few years is a real cost of ownership for decorative slabs.

Key Cost Drivers Beyond the Square Metre Rate

Two quotes for what looks like the same slab can differ by 30 to 40 percent. That is usually not a mistake. Site-specific factors can legitimately shift the price by thousands.

Excavation and Ground Preparation

Cutting down 100 mm of soil across a 60 m² garage slab, carting the spoil and compacting a gravel base adds real money. Rocky ground, high clay content (common across much of Brisbane, Adelaide and Melbourne's outer suburbs) or a sloping block pushes this further. Some quotes exclude excavation. Read carefully.

Reinforcement

A plain shed slab might use SL72 mesh only. A structural house slab in an M or H class reactive site uses mesh plus bar reinforcement to an engineer's spec. Steel prices have moved around in recent years, so jobs quoted months apart can vary on this line item alone.

Thickness

Standard residential slabs pour at 100 mm. Garages and workshops often go to 125 mm. Heavily loaded commercial floors may specify 150 mm or more. Every extra 25 mm of thickness is roughly 25 percent more concrete volume, and more pump time.

Formwork and Edge Profiles

Simple square slabs are quick to form. Curves, re-entrant angles and levels changes on sloping blocks all take longer and use more timber. Formwork labour is usually included in per-m² rates, but complex shapes attract a surcharge.

Concrete Pump Access

A pump adds roughly $600 to $1,200 to a job, depending on boom size and duration. If the truck cannot get within about 3 metres of the pour, a pump is usually non-negotiable.

Sealing

Most concreters apply a basic curing compound included in the rate. A penetrating sealer or coating-grade sealer is often quoted separately at $10 to $25 per m² applied.

Be cautious of quotes that exclude GST, excavation, formwork or pump hire unless those items are clearly itemised. A headline rate that looks cheap often has these costs added back later. Always confirm what is in and out of scope in writing before signing anything.

Regional Price Differences Across Australia

Labour and material costs shift noticeably between capital cities and regional areas. Sydney and Melbourne tend to sit at the upper end of national price ranges. Perth has historically priced competitively for slabs but has seen cost pressure in recent years due to strong construction activity. Rural and remote jobs attract travel, accommodation and sometimes a regional cement price premium on top of standard rates.

A few general patterns worth knowing:

Sydney and surrounds: High labour costs and difficult access in established suburbs push slab prices toward the top of ranges. Geotechnical reports are common on clay-heavy western and south-western sites.
Melbourne: Reactive soil (Class M and H) is widespread across suburbs like Werribee, Cranbourne and Frankston, which often means engineer involvement and extra reinforcement even for shed slabs on reactive ground.
Brisbane and South-East Queensland: Subtropical conditions mean curing is critical. Steel-trowel finishes in high humidity need careful timing. Concrete pricing is mid-range but excavation costs are real in hilly areas.
Adelaide: Competitive market, though reactive soils across much of the metro area add engineering costs to house slabs.
Perth: Sandy soil profiles in many coastal suburbs make for easier excavation, but the strong construction pipeline means concreters are busy and availability can affect pricing.
Regional and remote areas: Add 20 to 40 percent to metro estimates as a working assumption. Get quotes; do not rely on metro benchmarks for regional builds.

How to Get and Compare Concrete Slab Quotes

Three quotes is the standard advice, and it still holds. But three quotes are only useful if they cover the same scope. Here is how to make comparison practical.

Prepare a Clear Brief

Write down the slab dimensions, what it is for, what finish you want, whether you need excavation and who handles council crossovers or drainage. The more specific you are, the more directly comparable the quotes will be.

Ask What is Included

Every quote should spell out: concrete grade and thickness, reinforcement type, excavation, formwork, pump hire if needed, finish type, curing compound, GST, and any exclusions. If the quote is one line on a napkin, ask for an itemised version.

Check Licences

Concreting licence requirements vary by state. In NSW, Queensland and Victoria, structural concrete work requires a licensed contractor or a contractor working under one. Ask for their licence number and verify it on the relevant state building authority register.

Look at Their Work

Ask to see photos of finished slabs, ideally ones that are 12 to 18 months old. Cracks, surface crazing and poor edge profiles show up with time. Recent photos of a freshly poured slab look good regardless of quality.

Understand Payment Terms

A small deposit (typically 10 to 20 percent) to secure the booking is normal. Demanding 50 percent or more upfront before work starts is unusual and worth questioning.

The cheapest quote is not always the best value. A slab poured without adequate sub-base preparation, the wrong concrete grade or insufficient curing will crack and settle. Fixing a failed slab costs far more than getting it right the first time. Compare quotes on scope and quality, not just the bottom line number.

Concrete Slab Cost Guide (2026): Shed, House & Garage Slabs