Retaining Walls can be built from Concrete, Sleepers, Timbers, Boulders (Rock Walls) and can also be built in different ways – for example, interlocking, crib etc. In addition, some Australia Retaining Walls need Council Approval and others do not.
If you are tempted to construct a retaining wall without a building approval, you should be aware that there can be heavy penalties under the Building Act 1975 and the Integrated Planning Act 1997; check out GCCC regulations at :
Before thinking of engaging a builder, it is essential you are clear about what you want and what it has to do; only then can retaining wall builders give you accurate information – which will probably require an engineers input also.
The most durable Retaining Walls are built from Rocks / Boulders, Concrete Crib, Interlocking Concrete Blocks and Core Filled Blocks. Retaining Walls built from these materials can be expected to last 30-40 years. Concrete Sleepers tend to be slightly less durable.
Treated Timber Retaining Walls tend to have a lower life expectancy, typically 10 to 20 years. This is due to timber having several weaknesses – White Ants, and Rotting being the main two.
However, there are also pitfalls with stone and concrete walls., the main one being the space required. The redeeming features of Rock Walls are their long life.
One of the major issues with Rock Walls is that these are very dependent on the skill of the builder for stability; a Rock Wall that slides is no fun.