Concrete Slabs
A concrete slab is a flat, poured concrete pad used as a base for garden sheds, patios, alfresco areas, air conditioner units, garden studios and other small structures. Unlike a house slab, it doesn't need to carry the full engineered load of a building, but it still needs the right thickness, base preparation and reinforcement to stay flat and crack-free over time.
Pricing guide: How much does a concrete slab cost?
A basic concrete slab for a shed or small patio typically costs between $70 and $110 per square metre, depending on thickness, access and site preparation. Larger or more heavily reinforced pads cost more. Get quotes from local contractors for an accurate price on your job.
Why homeowners choose it
- Provides a stable, level base for sheds, patios and outdoor structures
- More affordable per square metre than structural house slabs
- Resists weeds, pooling water and ground movement better than pavers or gravel
- Can be finished plain, broomed, coloured or exposed to suit the space
- Low maintenance once cured and sealed
How it works
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1
Site marking and excavation
The pad area is marked out and topsoil excavated to the required depth for the base and slab.
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2
Base preparation
Crushed rock is spread and compacted to give the slab a firm, even foundation.
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3
Formwork and reinforcement
Timber or steel formwork sets the edges and levels, and mesh reinforcement is placed on chairs above the base.
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4
Pouring and finishing
Concrete is poured, screeded level and finished with a broom, trowel or other surface texture.
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5
Curing and joint cutting
Control joints are cut once the concrete has firmed up, and the slab is left to cure before use.
Hiring guide
Questions worth asking before you commit to a contractor.
Ask to see it, not just take their word for it. Insurance protects your property if something goes wrong on site.
Site preparation, disposal of old material, and any council permits can be included or charged separately — get it in writing before you compare quotes.
Some contractors do the work themselves; others subcontract parts of it. Neither is wrong, but you should know who is doing your job.
Old concrete, tree roots or drainage issues are common surprises. Ask how a change of scope gets costed before it happens, not after.
Materials usually carry a manufacturer's warranty. Ask specifically about the contractor's own workmanship warranty too.
Frequently asked questions
How much does a concrete slab cost?
A basic concrete slab for a shed or small patio typically costs between $70 and $110 per square metre, depending on thickness, access and site preparation. Larger or more heavily reinforced pads cost more. Get quotes from local contractors for an accurate price on your job.
How thick does a slab need to be?
Most small slabs for sheds and patios are 100mm thick over a compacted base. Slabs supporting heavier loads, such as a large shed or a spa, may need extra thickness and reinforcement.
Do I need a permit for a small slab?
A stand-alone slab usually doesn't need a building permit, but if it's forming the base for a shed, carport or other structure, the structure itself may need one. Check with your local council or building surveyor.
Can a slab be poured close to my house?
Yes, but ground levels and drainage need to be considered so water doesn't run back toward the house. A contractor will grade the slab with a slight fall away from the building.
Concrete Slabs in popular suburbs
Local pricing, FAQs and a map for these areas.
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