The quote, already started
⚠️ These are starting numbers, not market rates. Put your own in.
What the job actually is
- Confirm the slab design you are building to — thickness, strength, mesh and edge, from the shed supplier or an engineer.
- Set out the slab square and to level, and check the fall across the site.
- Excavate to grade and compact the base.
- Cart the spoil off, or agree where on site it goes.
- Lay and compact road base where the design calls for it.
- Set the formwork to the perimeter, including any thickened edge.
- Lay the vapour barrier, then the mesh on bar chairs at the right cover.
- Pour, screed to level, and float.
- Finish to what was quoted — broom, trowel or otherwise.
- Saw-cut the control joints at the right time, strip the forms, and tell the customer how to cure it.
Materials
- Ready-mix concrete at the strength specified — the concrete calculator works out cubic metres, 20 kg bags and the ready-mix order, and the mix ratio calculator covers a site-mixed batch.
- Road base or crushed rock for the sub-base — the gravel and aggregate calculator gives the order weight and volume.
- Reinforcing mesh and bar chairs, at the size and cover the design calls for.
- Vapour barrier and tape.
- Formwork timber, pegs and stakes.
- Any starter bars or edge thickening the design specifies.
- Curing compound, if that is how you are curing it.
Order the concrete a little over rather than exactly. The ground is never perfectly flat, a slab that runs short mid-pour is a cold joint you will be looking at forever, and a second small load costs far more per cubic metre than the first.
What the price assumes
- The design — thickness, strength, mesh and edge — has been provided, and is somebody else's cost.
- The site is reasonably level and the ground is ordinary: no rock, no deep fill, no services in the way.
- The truck can get within chute distance. This is the assumption that costs the most when it is wrong.
- Excavation to the depth quoted, and the spoil goes where the quote says.
- Approval, where it is needed, is already in hand.
- Power and water are available on site.
- Nothing has to be demolished or removed first.
Extras that come up
- A concrete pump, when the truck cannot reach. Hundreds of dollars and a longer pour.
- Rock, fill or a service line found in the excavation.
- Extra spoil, or spoil that has to leave the site rather than stay on it.
- Cut and fill on a sloping block, which can turn a slab into an earthworks job.
- Conduit or plumbing under slab, which is another trade and has to happen before the pour.
- A different finish — exposed aggregate, coloured or polished are all different days.
- Termite treatment, where it applies.
- Reinstating a verge, driveway or lawn the truck marked getting in.
Things nobody charges for, and should
- The set-out and the measure-up, plus a second visit to check levels.
- Waiting on the truck, which does not always arrive in the window.
- The saw-cut return visit, which is a separate trip at a specific time.
- Stripping the forms, another trip.
- Compaction hire for the plate or the roller.
- Consumables — form pegs, tie wire, blades, curing compound.
- Cleaning the barrow, the tools and the driveway before the concrete goes off.
A worked example
A 6 × 5 m shed slab on a flat site with reasonable access, 100 mm thick with thickened edges, 25 MPa, SL72 mesh over a vapour barrier, chuted straight off the truck, broom finish. Concreter registered for GST.
| Line | Qty | Rate | Total |
|---|---|---|---|
| Set out, excavate and level to grade | 30 m² | $34.00 | $1,020.00 |
| Cart spoil off site | 1 job | $620.00 | $620.00 |
| Road base — supply, spread and compact | 30 m² | $26.00 | $780.00 |
| Formwork to perimeter, incl. thickened edge | 22 lm | $46.00 | $1,012.00 |
| Vapour barrier and SL72 mesh, on bar chairs | 30 m² | $22.00 | $660.00 |
| Supply and place 25 MPa concrete, 100mm | 3.6 m³ | $315.00 | $1,134.00 |
| Screed, float and broom finish | 30 m² | $28.00 | $840.00 |
| Saw-cut control joints and strip forms | 1 job | $340.00 | $340.00 |
| Subtotal | $6,406.00 | ||
| GST (10%) | $640.60 | ||
| Total inc GST | $7,046.60 | ||
| Deposit (20%) | $1,409.32 | ||
| Balance on completion | $5,637.28 |
These are starting numbers, not market rates. Put your own in. Every figure above comes from the line items in the builder at the top of this page.
Start this quote in Yamate — the lines, not the prices →The app fills in the same line descriptions and leaves every amount blank for you. Your prices, not ours.
Yamate keeps your rates and your standard lines, so the next one of these is a few taps rather than a blank page — then turns the accepted quote into the invoice without retyping it.
FAQ
How much concrete does a shed slab need?
Area multiplied by thickness gives the cubic metres, and you order a little over because the ground is never perfectly flat. The concrete calculator works out cubic metres, 20 kg bags and the ready-mix order for slabs, footings and post holes.
Who pays if the truck cannot get close enough?
Whoever the quote says. If the quote is silent, the argument happens on the day with a loaded truck waiting and the meter running. Name the access the price assumes and what a pump costs, and the answer is already written down.
What thickness should a shed slab be?
That is a design question, not a rule of thumb — it depends on the structure, the loads and the site classification, and it comes from the shed supplier or an engineer. Quote the design you were given rather than deciding it.
Should I take a deposit for a slab?
Usually yes, because the ready-mix is paid for before it is placed and cannot be returned once it is on the truck. Put it on the quote as a percentage and check your state's rules on deposit limits.
Work out the materials first
More like this
General information for Australian tradies, not building, engineering, legal or financial advice. The rates on this page are starting points rather than market prices, and every figure is an estimate based on what you type in. Slab design, approval, licensing and deposit rules are set by the National Construction Code and by your state and council — check yours before relying on this page.