Concrete Volume
Estimating Concrete Volume
Whether you are pouring a slab for a shed, a driveway, or a foundational footing, ordering the right amount of concrete is critical. Ordering too little stops work; ordering too much wastes money.
The Formula (Volume)
Concrete is measured in Cubic Meters ($m^3$) or Cubic Feet ($ft^3$). The basic formula for a rectangular slab is:
Volume = Length × Width × Depth (Height)
Dry Mix Calculation (M20 Grade)
Once you know the wet volume, you need to calculate the dry materials (Cement, Sand, Aggregate). Concrete shrinks when water is added. We generally multiply the wet volume by 1.54 to get the dry volume.
- Cement: The binding agent.
- Sand (Fine Aggregate): Fills the voids between stones.
- Aggregate (Gravel): Provides structural strength.
Tips for Success
- Add a Safety Margin: Always order 5-10% extra to account for spillage, uneven ground, or formwork spreading.
- Check Depth: Ensure your depth measurement is consistent. A 4-inch (0.1m) slab is standard for walkways.