Casting a reinforced cement concrete slab is a critical phase in any building construction. A well-executed slab ensures structural strength, durability, and long-term performance of the building. For a site engineer, following a detailed checklist for RCC slab casting is essential to maintain quality, safety, and compliance with standards. This guide offers a practical, field-ready checklist covering every stage—pre, during, and post-slab casting.
Importance of Slab Casting Checklist
Slab casting is not just about pouring concrete. It involves careful planning, coordination between multiple teams, material control, formwork inspection, reinforcement checks, and concrete quality assurance. A thorough checklist helps:
Avoid construction delays and rework
Ensure safety of workers and structural members
Verify that codes and drawings are followed
Maintain quality and prevent honeycombing, cracks, or sagging
Document each stage of work for future reference
Types of RCC Slabs Used in Construction
One-Way Slab
Used when the slab is supported on two opposite sides. Load transfers in one direction only.
Two-Way Slab
Supported on all four sides. Load is distributed in two directions. Common in residential buildings.
Flat Slab
Slab rests directly on columns without beams. Used in commercial buildings for flexibility in partitioning.
Waffle Slab
A ribbed slab with a grid-like pattern underneath. Used for aesthetics and long spans.
Hollow Core Slab
Precast slab with hollow spaces to reduce dead weight. Often used in industrial or modular structures.
Pre-Casting Checklist for RCC Slab
A site engineer should verify the following before starting slab casting:
1. Formwork Inspection
Formwork must be properly aligned and fixed. Check for dimensions, level, plumb, and squareness. Ensure joints are sealed to prevent slurry leakage. Apply shuttering oil to allow easy removal. Support must be strong enough to bear dead and live loads.
2. Reinforcement Check
Match bar diameters and spacing with structural drawings. Check cover blocks are placed correctly (top, bottom, and sides). Verify overlap length (lapping) and binding with proper tie wire. Ensure chairs and spacers are used to maintain reinforcement height.
3. Electrical and Plumbing Conduits
Verify that all electrical conduits, pipes, and sleeves are fixed before concreting. Confirm sleeves for AC, plumbing, and electrical are secured and won’t move during casting.
4. Slab Openings and Embedments
Check that all openings for stairs, ducts, or elevators are correctly marked. Ensure inserts, sleeves, anchor bolts, and embedded pipes are placed as per the drawing.
5. Staging and Centering
Verify staging and centering system is strong and level. Confirm spacing of props and beams is as per design. Ensure vertical supports are resting on firm ground or base plates.
6. Safety Precautions
Barricade the slab area. Check for fall protection gear. Workers must use safety helmets, shoes, and reflective jackets. Keep firefighting equipment on-site in case of electrical mishaps.
Material Checklist for Slab Casting
Ensure availability and quality of materials before the concrete pour:
Cement – fresh and stored properly
Sand – clean and well-graded
Coarse Aggregate – of correct size and free from mud
Water – potable and clean
Admixtures – plasticizers, retarders if used
Shuttering Oil – for formwork release
Cover Blocks – of proper thickness
Vibrator – needle and plate type, working condition
Concrete Pump – tested and functional
Curing Materials – jute bags, water pipes, sprinklers
Concrete Checklist Before Pouring
Ensure the following steps before concrete placement:
Concrete grade and mix confirmed (e.g., M20, M25)
Slump test conducted for workability
Cube molds ready for sample collection
Concrete batching plant or mixer is calibrated
Check delivery time from plant to site
Truck mixer chute cleaned and aligned
Vibrators ready near slab pour zone
Watchman assigned to restrict access during casting
Checklist During RCC Slab Casting
1. Continuous Pouring
Maintain continuous pouring without joints for better bonding. Pour in layers if the slab is very thick. Avoid cold joints at any cost.
2. Vibrator Use
Use needle vibrator around reinforcement, especially corners and congested zones. Avoid over-vibration to prevent segregation. Move vibrator slowly and withdraw vertically.
3. Leveling and Finishing
Ensure proper leveling using straight edges or laser levels. Provide slope (1:100 or as per drawing) in toilets, balconies, or terraces. Finish slab surface using trowel or float.
4. Construction Joints (if required)
If pouring is stopped due to emergency, roughen the joint area and clean it properly. Use bonding agent or cement slurry during resumption.
5. Quality Control
Collect concrete cubes every 15 m³ or as per code. Record batch details (mix, time, location, cube number). Ensure temperature of concrete is within limits (not above 35°C).
Post-Casting Checklist for RCC Slab
1. Finishing and Marking
Finish surface within 30 minutes after final leveling. Mark beam/slab centerlines, grid lines, and column points on slab after 24 hours.
2. Curing
Start curing after 12 to 24 hours. Keep slab moist for a minimum of 7 to 14 days. Use water ponding, sprinkling, or curing compounds. Protect concrete from direct sun and wind.
3. Stripping of Formwork
Follow IS 456:2000 guidelines:
Side forms – 24 to 48 hours
Bottom of slab – after 7 days (with props)
Props removal – 14 days for spans under 4.5 m, 21 days for longer spans
Ensure concrete has gained sufficient strength before removal
4. Surface Protection
Avoid impact loads or stacking of materials during early days. Repair minor cracks or honeycombs immediately with approved methods.
Record-Keeping and Reporting
Keep daily records of slab casting with the following entries:
Date and time of casting
Concrete grade and mix used
Slump value
Cube test sample numbers
Worker attendance
Equipment used (vibrator, pump)
Weather conditions
Signature of site engineer and supervisor
Common Mistakes During RCC Slab Casting
Skipping slump test and cube test
Improper reinforcement placement
Not using vibrators properly
Overloading formwork
Inadequate curing
Ignoring construction joints
Pouring in rainy weather without protection
Safety Checklist for RCC Slab Casting
| Item | Checked? |
|---|---|
| Barricading of slab edges | ✅ |
| PPE for all workers | ✅ |
| First-aid kit on site | ✅ |
| Fire extinguisher available | ✅ |
| Vibrator and pump safety | ✅ |
| Rain protection setup | ✅ |
| Ladder/scaffolding safe | ✅ |
FAQs on RCC Slab Casting
What is the minimum curing period for an RCC slab?
The minimum curing period is 7 days for ordinary Portland cement and 10 days for blended cement, though 14 days is recommended for durability.
How many cubes should be cast per slab?
As per IS 456, three cubes for every 15 m³ of concrete or one set per floor is standard.
Can slab casting be done during rain?
Only if proper rain protection is arranged. Otherwise, postpone casting as water affects strength and bonding.
What is the ideal slump for RCC slab?
75 mm to 100 mm is ideal for slab concreting to ensure workability and prevent segregation.
How long should props be kept under a slab?
For spans less than 4.5 meters, props should be removed after 14 days. For longer spans, keep them for at least 21 days.
Is waterproofing done before or after slab casting?
Waterproofing is usually done after slab casting, once the surface is fully cured and dry.
