Retaining Walls in Adelaide
Trendscape builds engineered retaining walls for sloping blocks, pool surrounds, driveways and terraced gardens across Adelaide and the Adelaide Hills. Concrete sleeper, block, rendered and feature stone walls, with the drainage, ag-pipe, backfill and earthworks done properly by the one crew, so the wall is still straight in twenty years. Adelaide's reactive clay soils move with the seasons, which is why we size footings and drainage for the site rather than the brochure. Where a wall needs engineering or council approval we organise it. We can also cut in the steps, paths and exposed aggregate that usually go with a retaining job, and finish with planting. Free site visit and fixed written quote. Call Val on 0411 555 359.
Retaining Walls in Adelaide: Engineering, Council Rules and What They Cost
A retaining wall is holding back soil that wants to move, and in Adelaide that soil is usually reactive clay that swells every winter. The walls that lean, crack or bulge after a few years were almost always built without proper footings, drainage or engineering. We build sleeper, block, rendered and stone walls with the footings, ag-drain and backfill they need, and we get the engineering and council paperwork done when the height calls for it.
Do I need council approval for a retaining wall in South Australia?
As a general rule, a retaining wall up to one metre high can usually be built without development approval. Above one metre, or where a fence sits on top of the wall, or where the wall is close to a boundary or supports a building, you will normally need a development application with an engineer's design. Rules vary by council and by what the wall is retaining, so we check your site against them before quoting and manage the application if it is needed.
What does a retaining wall cost in Adelaide?
Concrete sleeper walls with galvanised steel posts are the most common in Adelaide and typically run $350 to $600 per square metre of wall face installed, depending on height, access and ground conditions. Rendered block walls and natural stone cost more. Excavation, disposal of spoil, drainage and any engineering are itemised in our fixed quote so there are no surprises.
Concrete sleepers, block or stone?
Concrete sleepers are the workhorse: fast, strong, termite-proof and available in smooth, textured and timber-look finishes. Rendered block walls give a clean architectural line and suit front yards and pool surrounds. Natural stone and gabion walls suit Hills properties and larger landscapes. Timber sleepers are cheaper up front but rot in Adelaide clay and we do not recommend them for anything you want to last.
How deep do the posts go?
For a sleeper wall, steel posts are set in concrete to roughly the same depth as the wall height above ground, so a one metre wall has posts a metre into the ground, and higher walls are designed by an engineer. This is the detail that most cheap walls skip.
Why does drainage matter?
Water is what pushes walls over. Every wall we build has an ag-drain at the base wrapped in geofabric and a free-draining gravel backfill behind the sleepers, with the drain run to a legal discharge point. Without it, wet clay loads the wall every winter until something gives.
Can a retaining wall go on the boundary?
Often yes, but the wall and its footing generally need to stay on your side of the line and there are notification requirements for neighbours where excavation or a fence is involved. We survey the boundary before we dig.
Can you also do the levels, steps and the landscaping?
Yes, and that is where a retaining wall makes sense. Most of our walls are part of a bigger job: creating a flat lawn on a sloping block, terracing a front yard, a pool surround or a driveway cut. We do the earthworks, walls, steps, paving, concrete and planting as one crew with one plan.
Where we work
We build retaining walls across metropolitan Adelaide and the Hills. North-east: Athelstone, Paradise, Campbelltown, Rostrevor, Tea Tree Gully, Golden Grove and Blakeview. East and inner south: College Park, Mitcham, Torrens Park and Goodwood. South: Flagstaff Hill, Warradale, Morphett Vale, Lonsdale and Huntfield Heights. West: West Lakes, Henley Beach, Henley Beach South and Ethelton. Hills: Mount Barker and the Adelaide Hills. If your suburb is not listed, call anyway. 30 years in Adelaide soil, owner on every job, fully insured. Call 0411 555 359 for a free site visit and fixed quote.