Frequently Asked Questions
How do I calculate how much concrete I need?
For a rectangular slab: multiply length × width × thickness (in metres) to get cubic metres. For a 5m × 4m slab at 100mm thick, that's 5 × 4 × 0.1 = 2 cubic metres. Always add 10% for wastage. Our Concrete Calculator handles slabs, circular areas and columns automatically.
How much does concrete cost in Australia?
Ready-mix concrete typically costs between $200–$350 per cubic metre in Australia, depending on your location, mix strength (MPa rating) and delivery distance. Metro areas tend to be on the lower end, while regional areas can be higher. Our Concrete Calculator uses an adjustable price per m³ so you can enter your local supplier's quote.
What wastage allowance should I use for flooring?
A standard wastage allowance for flooring is 10% for rooms with straight walls. For rooms with angles, bay windows or complex shapes, allow 15%. Timber flooring laid at 45 degrees can require up to 20% extra. Our Flooring Calculator lets you set your own wastage percentage.
Do I need a licensed builder for concrete slabs?
In Australia, any structural concrete work (foundations, footings, load-bearing slabs) must be carried out or supervised by a licensed builder or concrete contractor. Small non-structural slabs (e.g. garden paths, small garden sheds) may be DIY depending on your state's regulations. Always check with your local council before starting.