01/06/2025
Important Points to Check Before Casting a Slab
When inspecting a slab before concrete casting, there are several key points that must be carefully verified to ensure structural quality and code compliance:
1. Presence of Concrete Cover
The concrete cover is essential to prevent honeycombing in the slab and to protect the reinforcement from environmental exposure.
2. Check of Top and Bottom Additional Reinforcement
Ensure that additional reinforcement is placed correctly in both the top and bottom layers. In case of a cantilever (drop), the additional steel should be placed in the top mesh only.
3. Lap Splice Length (Overlapping of Bars)
Confirm that the lap length between rebars complies with the building Code, which requires a minimum overlap of 60 times the bar diameter (60D).
4. Beam Reinforcement Inspection
Verify beam reinforcement arrangement. Pay special attention to the placement of additional steel:
• Bottom third of the beam (bottom reinforcement)
• Middle third (top reinforcement)
5. Spacing Between Rebars
Ensure the spacing between rebars matches the shop drawings.
6. Column Location Verification
Confirm that column locations and dimensions are correct using offset lines to ensure precise placement.
7. Rebar Tying
Check that rebar ties are distributed uniformly and not concentrated in one area to maintain structural integrity.
8. Cleanliness of the Slab
Make sure the slab surface is thoroughly cleaned and blown out before pouring the concrete.
9. Partial Casting Strategy (if needed)
If the slab cannot be cast in one pour, it should be divided and poured up to the first or last third, as the moment at these points is nearly zero. Additional reinforcement must be provided at the construction joint for both slab and beam continuity.
10. Leveling Strings (Wires) for Pouring Level
Install leveling strings or wires to define the concrete slab level and ensure it is consistently maintained during pouring.
11. Thickness of Reinforcement
