We specialise in building steel reinforced concrete block retaining walls in Sydney, which are generally considered to be one of the best solutions without the need for heavy duty plant and equipment compared with piling for example, and can be built plumb with a cantilevered footing to maximise on space. These types of retaining walls are commonly used to retain anything up to 3.4m. We can provide designs or build to engineers' specifications where required.
What we handle
- Demolition of existing structures
- Excavation
- Concrete footings
- Reinforced concrete block construction
- Render or paint finishes
- Drainage behind the wall
- Timber paling boundary fences on top, where required
Demolition, excavation, and concrete footings
We take care of the demolition of old failed retaining walls and brick fences, excavations, formwork, shoring, steel reinforcing, and placing of new concrete footings. Most of our clients prefer to deal with one contractor that handles everything. And we prefer to build on footings we have prepared, because we take great care in levelling the concrete and setting out reinforcing starter bars correctly for block laying without having to cut blocks or bend reinforcing bars.
Retaining wall design and construction
Concrete block retaining walls are certainly the preferred method of construction for retaining applications above 1m high, especially in tight access areas such as existing residential back and side boundaries where neighbouring blocks are above or below each other, often separated by old brick or stone retaining walls that are failing and need to be replaced (if they haven't already collapsed).
Why retaining walls fail
The most common causes for the failure of retaining walls are usually a combination of bad drainage of water that builds up behind retaining walls following heavy rain, inadequate sized footings rotating under pressure, inadequate wall thickness, and tree roots.
Engineering and DA approvals
In NSW any retaining wall over 1m (whether it's a new one or a replacement) will need a Development Application (DA) and therefore will need an engineer's certified design and site inspections to sign off on the construction at various stages. We work closely with a Chartered Professional Structural Engineer who can provide these services when needed.
Combined with brick fences
It's very common for a brick fence to also act as a retaining wall for properties above or below street level, or to create planter boxes or level spaces in the garden for lawns. When this is the case it's very important to consider the design. Generally, if a brick fence is retaining more than 600mm it's good practice to incorporate a concrete block retaining wall to deal with the lateral forces and install ag lines to move water away. This can all be done without compromising the look of the brick fence by adding a facade of bricks in front of the blocks.
See the brick fences page for the brickwork side.