From a DIY job at home to an engineering project, concrete is a diverse product that is adaptable and well-utilised throughout New Zealand. Here, we break down what you need to know for general-purpose DIY cement projects, and give advice on the use of ready mix concrete.

Ground and formwork preparation

  • Clear the site beyond the edges of the slab to allow enough room for setting out pegs and formwork.
  • Dig out to the required depth of the slab (nominal 100mm) allowing additional depth for a layer of sub base (100mm).
  • Ensure sufficient compaction of the sub base.
  • Formwork acts as a mould for the concrete and is commonly made from 25mm thick timber. Timber should be clean, smooth and not flex under the weight of the concrete.
  • Run string lines first to the desired level, then put the formwork up to the line and peg as you go. Allow for a fall for drainage if required.

DIY Info

Materials to use
Health and Safety

Concrete mixing and placing

What to consider before you start
How to mix concrete
Prescribed mixes

Recommended mixes and working out quantities

Recommended concrete mixes and raw material quantities
Amount of concrete required for Slabs, Driveways and Paths
Amount of concrete required for Fenceposts and other round excavations