You're standing at the bottom of a backyard that falls away towards the back fence, and the client says they want it levelled, with a wall across the back and paving up top. Before the tape's even out, you're doing sums in your head. If you've ever typed "retaining wall cost per metre" into Google to sanity-check those sums, you'll know what comes back is written for the homeowner, not for the person digging the footing.
Retaining walls are bread and butter for most of us. They're also one of the easiest places to leak margin, because a wall looks simple on a quote and it isn't. So this is how I'd build one up from the contractor's side, a lineal metre at a time.
Why the retaining wall cost per metre online doesn't price your job
Have a look at what's out there. RetWall puts an installed, engineered Besser block wall at $400–$700 per lineal metre at 1.0 m high, $600–$1,000 at 1.5 m and $800–$1,400 at 2.0 m. Those are 2025 figures that include basic drainage, and RetWall doesn't say whether GST is in or out. Built Simple has rendered or clad Besser block at $320–$450 a metre, but that's a metro figure, ex-GST, for walls up to 1.2 m on flat sites with good access. Karven prices per square metre of wall face instead, GST inclusive: $450–$800/m² for core-filled block and $500–$1,000+/m² for natural rock or sandstone block.
Three sources, three different bases. None of them know your site, your access, your crew or your overheads. They're handy for knowing roughly where the client's head is at when they've done their own research. They're not your quote.
Build it up per lineal metre, not per wall
Say the job is 18 lineal metres of rendered block at 1.0 m high. That's 18 m² of wall face, which is worth working out because block, render and drainage aggregate all scale with face area, while footing and ag pipe scale with length.
The line items I want to see on that quote:
- Excavation for the footing and the cut behind the wall, and where the spoil goes. Dirt comes out bigger than it went in, so price skip bins or truck loads on the loose volume, not the hole.
- Footing concrete, reo, starter bars, and whether you need a pump.
- Blocks and core fill.
- Render, and who's doing it. A rendered block wall is really two jobs.
- Drainage (more on that below).
- Backfill and compaction.
- Capping, if there is any.
- Labour, item by item, with access honestly factored in. Hand dug and barrowed in down a side path is not the same job as a mini excavator walking straight in off the street.
And watch height. RetWall says doubling the wall height roughly triples the construction cost. So don't take your 1.0 m rate and add half for a 1.5 m wall. That's a quick way to work for nothing.
Rendered block, sleepers or stone
Sleepers are usually the cheaper option to put in front of a client. RetWall's table lists treated timber sleeper at $200–$400 a metre for 1.0 m high. On your side, the take-off is post holes, concrete, posts, sleepers and cuts, and it goes up quicker than block.
Rendered block is more line items and more trades, as above, and the render is where I see people underquote, because it gets added as an afterthought.
Stone is a different beast again. It's heavy, the handling time is real, and you'll want a machine for anything decent. Price the labour like you mean it.
Whatever the client picks, quote the material they've chosen with the build-up it actually needs. Don't let a sleeper wall carry a block wall's drainage allowance or the other way round.
Drainage is a line item, not an afterthought
This is the one I'd circle in red. Karven calls ag pipe, free-draining gravel and weep holes a real cost and the most common corner cut on cheap quotes. In their worked example, a 12 m by 1 m concrete sleeper wall, they allow $900 just for ag drain, gravel backfill and weep holes.
RetWall's drainage guide spells out the spec: 100 mm perforated PVC in a geotextile sock at the base of the wall behind the footing, falling at a minimum of 1:100 to the discharge point; a 200–300 mm zone of clean 20 mm aggregate behind the wall, with no fines, so not crusher dust and not road base; and weep holes of 50–75 mm PVC at 1.5–3.0 m centres.
So take it off like any other quantity. On our 18 m example, that's 18 m of socked ag pipe plus the run to wherever the water's going. Weep holes at 2 m centres is around nine or ten. A 300 mm drainage zone, 1.0 m high, over 18 m is about 5.4 m³ of 20 mm aggregate before you allow for anything else. And ask yourself where that water actually ends up, because a long run to a legal discharge point is a cost too.
RetWall says saving $500–$1,000 by skimping on drainage is false economy. I reckon any landscaper who's been around a while has seen a wall that proves it.
Engineering and approvals depend on your state
There's no single national rule here, and I'd be wary of anyone who tells you there is. RetWall's guide on engineers says each state has slightly different rules, and individual councils can be stricter.
In Victoria, RetWall says a building permit is generally needed for walls over 0.6 m on or near a boundary, and over 1.0 m regardless of location. Check that with a building surveyor for your job before you rely on it.
In Queensland, Salt Landscaping explains that council building approval isn't needed for a wall under 1 m with no load above it and at least 1.5 m clear of any building or wall. But licensing is a separate question: Salt says any building work over $3,300, materials, labour and GST included, has to be done by someone with the right QBCC licence. Their example is a 600 mm sleeper wall in a $30,000 garden upgrade that still needs a licensed contractor even though no permit is needed for the wall itself.
When engineering or a permit is in play, RetWall puts the add-ons at $600–$1,500 for engineering, $500–$1,500 for a building permit and $300–$800 for a soil report if you need one. Built Simple suggests adding 20–40% for steep blocks, restricted access, engineering certificates or removing an existing wall. If you're not carrying those costs yourself, say clearly on the proposal what's excluded.
Don't rely on memory at the site walk
Most of the margin on a wall is lost on the site walk, not at the laptop. You forget to note the side gate is 900 wide, or that there's an old wall to come out. That's why we built Ask Willow to prompt for the hidden stuff: soil expansion, skip bins, access and slope. It also asks things like whether to allow for a concrete pump when access is tight. It's not perfect, and it can't measure off a plan, so you still measure your lineal metres on site and check the numbers. I almost always change something when I review it, and I usually add some labour hours.
The takeaway
When a client asks what discount I can do, I tell them we don't discount, but I'm happy to change the scope. A shorter wall, sleepers instead of rendered block, a staged job. What I won't take out is the drainage, the footing or the engineering, because that's where cheap walls come from.
So on your next wall quote, build it up per lineal metre, scale for height properly, put drainage on its own line with real quantities, and check the rules for your state and council before you send it.
Sources
- Do landscapers need a QBCC licence in Queensland? | Learning Centre | Salt Landscaping
- Do I Need a Retaining Wall Engineer? | Complete Guide | RetWall
- Retaining Wall Costs Australia | Price Guide | RetWall
- Retaining Wall Cost Australia (2026): Per Metre Pricing
- How much does a retaining wall cost in Australia? (2026 guide)
- Retaining Wall Drainage Design | The Complete Guide | RetWall