Job takeoff
Concrete slab takeoff
Concrete, reinforcement and formwork for a ground slab from one set of dimensions.
A takeoff is the trade word for the shopping list a job produces — every material, and how much of each, worked out by its own cited calculator.
- 3Measurements in
- 3Trades out
Give the job once
Every figure on the right follows these, in the units you choose.
Been given a quote for this job?
Paste it into the concrete slab quote check: each line is read against these same calculators — what it leaves out, what it adds, and what to ask.
Check the quoteEvery trade, from those dimensions
then change a dimension, and each line shows what moved.
| Trade | Quantity | |
|---|---|---|
Concrete CalculatorVolume including a waste allowance.
Why this quantity?
Resting on
The waste factor: the calculator's working figure, a trade convention. | 3.44 cubic yards | |
Rebar CalculatorReinforcement on a standard grid, with an allowance for lap splices.
Why this quantity?
Resting on
The lap-splice allowance: the calculator's working figure, a trade convention. | 21 x 20 ft sticks | |
Concrete Formwork CalculatorEdge formwork around the pour, as deep as the slab.
Why this quantity?
Resting on
The cutting allowance: the calculator's working figure, a trade convention. | 9 x 8 ft boards | |
Concrete CalculatorVolume including a waste allowance.
Why this quantity? | 2.64 m³ | |
Rebar CalculatorReinforcement on a standard grid, with an allowance for lap splices.
Why this quantity? | 11 x 12 m sticks | |
Concrete Formwork CalculatorEdge formwork around the pour, as deep as the slab.
Why this quantity? | 10 x 2.4 m boards |
Estimates, not a quote. Each row gives its base, the allowance on top, the adjusted figure and what to order; change an allowance on the row, or open its reasoning to see every figure it rests on. A trade's own page carries what it does not cover — open the one you are about to order against.
Labour and programme
Person-hours for the rows going in, from trade rules of thumb: a range for each piece of work, never a price.
- Concrete5.7 h (2.9–12)
- Concrete Formwork2.0 h (1.2–5.0)
About 7.8 person-hours in the rows that carry them, between 4.1 and 17.
Trade by trade
- Labourer2 labourers + 1 mason + 1 plant operatorunder a quarter of a day
- Carpenter1 carpenter + 1 labourerunder a quarter of a day
About half a day, one trade after another at eight hours a day. Left out: drying and curing, deliveries, inspections, trades overlapping.
1 row carries no hours of its own
- Rebar: Fixing reinforcement is not rated here: the bar schedule, the shapes and laps it sets, and the inspection before the pour change its time several-fold.
Labour and programme
Person-hours for the rows going in, from trade rules of thumb: a range for each piece of work, never a price.
- Concrete5.8 h (2.9–12)
- Concrete Formwork2.0 h (1.2–5.0)
About 7.8 person-hours in the rows that carry them, between 4.1 and 17.
Trade by trade
- Labourer2 labourers + 1 mason + 1 plant operatorunder a quarter of a day
- Carpenter1 carpenter + 1 labourerunder a quarter of a day
About half a day, one trade after another at eight hours a day. Left out: drying and curing, deliveries, inspections, trades overlapping.
1 row carries no hours of its own
- Rebar: Fixing reinforcement is not rated here: the bar schedule, the shapes and laps it sets, and the inspection before the pour change its time several-fold.
Setups you have saved
The build-up, the dimensions and any allowance you changed — kept on this device, and reusable on any job. Your prices are not copied in: they stay in your price book, so a setup never holds a stale one.
How far does a budget go?
At your own prices, with this build-up unchanged.
About this job
A ground slab is three separate orders that all come off one set of dimensions: the concrete itself by volume, the reinforcement by area, and the formwork by perimeter. They scale differently — double the length and the volume and the steel double, but the perimeter does not — which is exactly why estimating them together from one measurement is more reliable than estimating them apart.
Thickness is the input that carries the most risk on this page. It is a design decision, not a rule of thumb: a slab carrying a wall, a vehicle or a machine base is sized by an engineer against the ground it sits on, and a figure taken from a similar job is a guess about somebody else's soil.
How each line reads
- Base
- What the calculator gives for these dimensions, before anything is added.
- Allowance
- Cutting waste, a lap or spare stock — named, with where it comes from, and changeable on the row.
- Adjusted
- The base with its allowance on top.
- Order
- What to buy: the adjusted figure in whole boards, bags, rolls or lengths.
The order this happens in
Quantities do not tell you the sequence, and on this job the sequence is where the money goes wrong.
- Excavate to formation and remove the spoil.
- Lay and compact the sub-base in layers — a slab is only as good as what it sits on.
- Set the formwork to line and level, braced against the pour's pressure.
- Damp-proof membrane and any under-slab insulation, lapped and taped.
- Reinforcement on chairs, at the cover the design calls for, with laps to the drawing.
- Pour, compact, finish and then cure — curing is a step, not an afterthought.
What this takeoff does not cover
- Any structural design. Thickness, mesh size, bar spacing and cover are an engineer's figures for your ground and your loading; this page takes them as given.
- Excavation, spoil removal and the sub-base — none of which is derived from the slab's own dimensions.
- Damp-proof membrane, radon barrier and under-slab insulation.
- Chairs, tying wire and edge thickenings. Laps are in the rebar row, as a flat allowance on the bar length.
- The pour itself: pump hire, access, curing compound, and cold or hot weather protection.
Quote check
Been given a quote for this job?
Paste it into the concrete slab quote check. Every line of it is read against these same calculators and your measurements. Quantities only, never prices.
What it leaves out
Every line this takeoff has that nothing on the quote reads as.
What it adds
Labour, removal, hire, fees — each named for what it is.
What to ask
One list of questions, ready to copy. Never a verdict.
More takeoffs
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Run this takeoff
Frequently asked questions
- What does the concrete slab takeoff give for a typical job?
- Opened at Slab length 6 m · Slab width 4 m · Slab thickness 0.1 m, it orders: Concrete, 2.64 m³; Rebar, 11 x 12 m sticks; Concrete Formwork, 10 x 2.4 m boards. Opened at Slab length 19.5 ft · Slab width 13 ft · Slab thickness 4 in: Concrete, 3.44 cubic yards; Rebar, 21 x 20 ft sticks; Concrete Formwork, 9 x 8 ft boards. Every figure follows the dimensions you give it.
- Which calculators does the concrete slab takeoff run?
- 3 calculators, one to a line: Concrete Calculator, Rebar Calculator, Concrete Formwork Calculator. Each has a page of its own with its formula and its sources; the takeoff runs them all on one set of dimensions.
- What does the concrete slab takeoff leave out?
- 5 things, each named on this page: Any structural design; Excavation, spoil removal and the sub-base; Damp-proof membrane, radon barrier and under-slab insulation; Chairs, tying wire and edge thickenings; The pour itself.
- Can I check a quote for this job against the takeoff?
- Yes. The concrete slab quote check reads a quote's lines against these same calculators and your measurements, and reports what it leaves out, what it adds and what to ask. It reads quantities, never prices.