Split the slab into bays no larger than one day's pour, then cast alternate bays first and the infill bays after a waiting period. A 40 × 30 m slab, 200 mm thick (240 m³), with 60 m³ a day, becomes four 20 × 15 m bays: A1 and B2 first, then B1 and A2 three days later.
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Concrete Pour Sequence Planner
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Pours needed
4bays of 20.00 × 15.00 m
Volume per bay
60.0 m³
Last pour
Sat, 7 Nov 2026
Pour 1: Mon, 2 Nov 2026
Bay A1 first set
Pour 2: Tue, 3 Nov 2026
Bay B2 first set
Pour 3: Fri, 6 Nov 2026
Bay B1 infill
Pour 4: Sat, 7 Nov 2026
Bay A2 infill
Bay sizes and joint positions must match the joint layout on the drawings: check with the engineer before setting out.
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Total = 40.00 × 30.00 × 0.200 m = 240.0 m³ → at most 60.0 m³ per pour → 2 × 2 bays
Checkerboard: bays where column + row is even go first, so no two fresh bays touch; the infill set starts 3 days after the last first-set pour
Bays are labelled by column letter (A, B, …) along the length and row number across the width
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Generated with myconstructioncalculator.com. Estimates for planning and ordering only; verify against drawings and specifications.
Method
Bays = ⌈total volume ÷ maximum daily pour⌉, arranged in columns × rowsFirst set = bays where column + row is even (no two touch)Infill set = remaining bays, starting the waiting period after the last first-set pourOne bay per pour day, on your chosen working days
Worked Example
40 × 30 m slab, 200 mm thick (240 m³), 60 m³ per day, 3-day wait, Monday–Saturday, starting Monday 2 November 2026:
Pour
Date
Bay
Set
1
Mon 2 Nov
A1
First
2
Tue 3 Nov
B2
First
3
Fri 6 Nov
B1
Infill
4
Sat 7 Nov
A2
Infill
Bays are 20 × 15 m, 60 m³ each. Columns are lettered along the length and rows numbered across the width.
Frequently Asked Questions
What is a checkerboard pour sequence?
Casting alternate bays first (like the black squares of a chessboard) and the remaining bays later, so that each new bay is placed against concrete that has already done some of its early shrinkage.
How big should each pour bay be?
No larger than the crew, pump and plant can place and finish in one shift, and arranged so the joints fall where the drawings show construction or movement joints.
How long should I wait before pouring the infill bays?
It depends on the specification: commonly a few days to a week. The calculator lets you set the gap.
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