Posted by Fair Trading NSW
on 2 October 2018
Fair Trading's building inspectors receive approximately 2400 complaints each year and many of those complaints relate to concrete driveways and paths cracking and/or displacing. When managing these complaints our inspectors refer to Australian Standard 3727.1 Paving - Part 1 Residential.
The standard is written and maintained by industry experts and is accepted as the 'minimum industry practice'. All builders and concretors should be familiar with this standard as it will give you a better chance of avoiding issues such as random cracking.
Some important things to remember:
If the foundation is not solid, the paving will not stay intact. Make sure the ground you are placing the concrete on is firm and even. Compaction or a suitable fill should be used where necessary.
Drainage is important to maintain the integrity of the pavement. Ensure the paving is sloped away from the building and any surface water doesn't settle at the paving edge.
Use joints to control planned cracking and to avoid random cracking.
The standard specifies that the slab's reinforcement must stop 50mm either side of the joint, it cannot be continuous.
The standard specifies maximum distances between control joints for different thickness and strengths of concrete and the sizing of the reinforcement used.