About this code
The foundational Indian Standard for design and construction of plain and reinforced concrete structures. Covers materials, workmanship, inspection, durability, and structural design. Every concrete project in India references IS 456.
Key sections
- 01Section 1: General
- 02Section 2: Materials, Workmanship, Inspection & Testing
- 03Section 3: General Design Considerations
- 04Section 4: Special Design Requirements
- 05Section 5: Structural Design (Limit State Method)
- 06Annex A-J: Design tables and detailing
Critical clauses
Mix shall be designed to achieve target strength based on standard deviation.
In practiceUse IS 10262 for design mix; nominal mix only up to M20.
Slump must match placement method and section depth.
In practiceSlump 75-125 mm typical for RCC pumped concrete.
Min cement content, max w/c, and cover based on exposure (mild to extreme).
In practiceSevere exposure: 320 kg/m3 cement, w/c 0.45, M30 minimum.
Nominal cover 20-75 mm depending on exposure and member type.
In practiceSlabs 20mm mild, 50mm severe; footings 50mm minimum.
Min 7 days for OPC, 10 days for blended cements.
In practiceContinuous moist curing; ponding or wet hessian.
Strength accepted if mean of 4 cubes >= fck+0.825σ and individual >= fck-3.
In practicePlan QC sampling from day one to satisfy this.
Practical implications
Reference clause 7 for durability, clause 26 for detailing.
Design mix per 9.2; cube QC per clause 15-16.
Cover, compaction, curing — clauses 13, 14, 15.
FAQs
Yes — it is referenced by the National Building Code and all municipal byelaws.
No — refer to IS 1343 for prestressed concrete.
M20 for general RCC; M25 for severe exposure; M30 for very severe.
Purchase the official Bureau of Indian Standards publication for the complete, legally-binding text.
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