Step-by-Step Slab Casting Checklist

Introduction

Slab casting is a critical activity on every construction site. Missing a single check can lead to rework, cracks, or failure. This step-by-step checklist helps you cast slabs correctly and avoid common mistakes.

Related: Cement Calculator, BBS Generator, Staircase Calculator, DPR Reports.

Before Casting – Shuttering Check

1. Shuttering / Formwork

• Centering is firm and properly supported (props, beams, shores)
• No gaps or leakage at joints
• Surface is clean (no hardened concrete, mud, or debris)
• Oil/grease applied to prevent sticking
• Level checked – top of slab at correct height (use auto level)
• Corners and edges properly aligned
• Opening for stairs, ducts, etc. correctly boxed

2. Reinforcement (Steel)

• Bar bending schedule (BBS) followed – use BBS Generator for schedules
• All bars in place – main bars, distribution bars, extra bars at supports
• Lap length and overlap as per code
• Cover blocks installed (bottom, top, sides)
• Spacers/chairs for top mat to maintain clear distance
• Tie wires properly fixed – no loose bars
• Stool height correct for slab thickness
• Cantilever and edge reinforcement as per drawing
• Development length at supports

3. MEP and Services

• Conduit pipes for electrical fixed and secured
• Sleeves for plumbing, AC, ducts in correct position
• No conflict with reinforcement
• Openings sealed to prevent concrete leakage

4. Materials Ready

• Cement – grade and quantity as per design
• Sand – washed, sieved
• Aggregate – 20mm or 10mm as specified
• Water – clean, potable
• Admixtures (if used) – correct dosage
• Cement calculator used for quantity check

5. Equipment and Labour

• Pump or conveyor ready (if used)
• Vibrator(s) available and working
• Labour count sufficient for pour and finishing
• Supervisor and mason present
• Site access clear for material delivery

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During Casting

6. Concreting Process

• Pour in one direction, avoid cold joints
• Proper compaction with vibrator – no over-vibration
• Top surface leveled with straight edge
• Float finish or trowel as required
• Edges and corners properly finished
• Sample cubes cast (typically 3 cubes per 50–100 m³)
• Date and location marked on cubes

7. Quality During Pour

• No segregation – concrete uniform
• No excess water added on site
• Slump checked (as per design)
• Temperature of concrete within limits (especially in summer)

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After Casting

8. Curing

• Curing started within 24 hours (earlier in hot weather)
• Surface kept moist for minimum 7 days (14 days preferred)
• Curing compound or wet gunny bags / plastic sheet
• No traffic on slab during curing period
• Edges and sides also cured

9. Shuttering Removal

• Removed only after required strength (see FAQs)
• Slab soffit: typically 14–21 days
• No premature removal – can cause cracks and deflection
• Props under slab may be "re-propped" for 2–3 weeks more if needed

10. Final Checks

• Surface even – no honeycombing
• No visible cracks (hairline may appear – monitor)
• Levels within tolerance
• Cube test results documented
• Update DPR with slab completion and progress

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Quick Reference Table

Phase	Key Checks
Before	Shuttering tight, reinforcement per BBS, cover blocks, MEP sleeves, levels
During	Proper compaction, no segregation, cubes cast, finish correct
After	Curing 7–14 days, no early deshuttering, cube results

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Summary

Use this checklist before every slab pour. Pre-cast checks prevent most defects. During casting, focus on compaction and finish. After casting, cure properly and remove shuttering only when safe.

For levelling, see How to Use Auto Level. For site documentation, use Yojo DPR and contractor app.