Ridges, plains and wetlands
The southern suburbs sit across two quite different landscapes. Closer to the coast and the river, through Applecross, Mount Pleasant, Bicton, Bateman and Bull Creek in the City of Melville, and through Spearwood, Coogee, Hamilton Hill and Bibra Lake in the City of Cockburn, the land rises over limestone ridges covered in yellow sand. Blocks there are often sloping, sometimes steeply, and limestone may sit only a short way below the topsoil.
Head south-east into the Cities of Canning, Gosnells and Armadale and the land flattens out. Suburbs like Willetton, Canning Vale, Southern River, Harrisdale and Piara Waters sit on grey sand plains dotted with wetlands, drains and low ground. Water, rather than slope, is the main issue there.
On the limestone ridges
On the ridges the typical jobs are boundary walls between houses at different heights, terraced back gardens, and walls along the street where front gardens sit above the footpath. Many homes in these suburbs date from the 1960s to the 1990s, and their original limestone walls are now old enough to need repair.
When digging footings or post holes here, builders often meet limestone caprock. That gives a firm base in some spots but slows excavation in others, and it can mean bringing in a rock breaker. A builder who has looked at the site will allow for it; a quote from a photo can't.
Limestone walls suit the look of these suburbs well, and natural cut limestone is often used to match older walls on the same street. Where a boundary is tight, concrete sleeper walls are a common alternative.
On the plains
On the flatter estates to the south-east, walls tend to be lower but drainage matters more. Lots are usually built up on imported sand to lift house pads above the natural ground, and developers retain the edges between lots, often in limestone. Owners then add their own garden walls, steps and raised beds.
Because the natural water table is closer to the surface in parts of these suburbs, ground behind a wall can stay wet for long periods in winter. Drainage needs an outlet that will actually work in July, not just in summer, and footings need to suit damp sand.
Common repair calls
South of the river, repair requests usually come from:
- Older limestone walls on sloping blocks that were built without drainage pipes
- Walls that have had extra fill, a shed or a pool added on the high side
- Timber garden walls from the 1990s and 2000s that are now rotting at the base
- Estate walls disturbed by later landscaping or digging close to their footings
Our repairs page explains the difference between patching, partial rebuild and replacement.
Approvals south of the river
Each local government sets out its own requirements, so the answer for a wall in Melville may differ in detail from one in Gosnells. Height, closeness to the boundary, fill and what the wall supports all come into it. Read our approval guide and confirm with your council before work begins.
Get a quote
Call 08 7666 2963 or send the form with your suburb, photos and a rough height and length. A local builder will look at the site and give you a written price. The cost guide has planning ranges if you want a budget first.