Retaining Walls
Engineered retaining walls for sloping and cut-and-fill sites.
We cover 5 regions and 226 suburbs across Victoria. Pick your area below. Each page covers the councils, site conditions and permit considerations specific to that part of the state.
What retaining walls actually involves
A retaining wall holds back ground. That sounds obvious, but it is the reason retaining walls are engineered structures rather than landscaping features. The load behind them is constant and it increases dramatically when the soil is saturated.
Most failures are water failures, not load failures. A wall built without free-draining backfill and a drain behind it accumulates hydrostatic pressure every time it rains heavily, and eventually moves. The drainage you cannot see is what determines whether the wall is still straight in fifteen years.
Technical requirements
- Permit thresholds for wall height in Victoria
- Engineering design, surcharge loads and drainage
- Agricultural drain and free-draining backfill
- Soil classification and footing depth
How the job runs
- Survey levels and determine what is being retained and what loads sit behind it
- Obtain engineering design appropriate to the soil classification
- Confirm the permit position for the wall height and situation
- Excavate and construct footings to the design
- Build the wall, installing agricultural drain and free-draining backfill as you go
- Backfill, compact and finish drainage outlets
What goes wrong
The failures we get called out to fix are consistent. These are the ones worth asking any builder about before you engage them.
- No agricultural drain behind the wall
- Backfilling with the excavated clay instead of free-draining material
- Building to a height that needed a permit and engineering without either
- Not resolving boundary responsibility with the neighbour in writing first
Tell us the address, we will tell you what applies
Tell us the address and what you are planning.
We reply the same business day.
Retaining Walls by area
5 regions, 226 suburbs. Each page is specific to that area.
Geelong & the Bellarine
68 suburbs around Geelong
Retaining Walls in Geelong & the Bellarine →Inner East Melbourne
57 suburbs around Camberwell
Retaining Walls in Inner East Melbourne →Inner West Melbourne
33 suburbs around Footscray
Retaining Walls in Inner West Melbourne →Hume & Craigieburn
29 suburbs around Craigieburn
Retaining Walls in Hume & Craigieburn →Yarra Ranges & Dandenongs
39 suburbs around Lilydale
Retaining Walls in Yarra Ranges & Dandenongs →Common questions
These answers apply wherever the job is. Anything specific to your area is on the relevant area page above, and anything specific to your property is a conversation.
Do I need a permit for a retaining wall?
In Victoria a building permit is generally required once a retaining wall passes a defined height, and lower walls can still need one where they support a driveway, a structure or a surcharge load. Because the threshold and its exceptions depend on the situation and the council, treat any wall above knee height as needing a check rather than assuming it is exempt. Engineering design is a separate requirement from the permit itself.
How deep do the footings need to go?
That is set by the engineering design, which depends on the wall height, the soil classification, what is behind the wall and whether anything is loading it from above. Reactive clay sites, which are common through Melbourne's west, generally need deeper or wider footings than sandy or rocky ground. This is not something to estimate from a rule of thumb. It comes from a site-specific design.
Who is responsible for a retaining wall on a boundary?
This depends on why the wall exists and who benefits from it, and it is a common source of neighbour disputes. As a general position, the party who created the change in ground level is usually responsible for retaining it. Where responsibility is genuinely unclear, it is worth getting it agreed in writing before work starts rather than after.
How do you stop a retaining wall from failing?
Most retaining wall failures come down to water, not load. Without free-draining backfill and an agricultural drain behind the wall, water pressure builds up and pushes the wall over, no matter how solid it looks. Proper drainage, correct engineering for the actual soil, and adequate footings are what determine whether a wall lasts.