| Primary value | 230 mm width (for 450 mm deep beam (D / 2 to 2D / 3)) |
| Applies to | Conventional rectangular RCC beams · Beams concealed inside 230 mm or 300 mm walls · Plinth and tie beams |
| Exceptions | Minimum width for fire / detailing → 200 mm |
| Beam matching block-wall thickness → 230 mm or 300 mm | |
| Wide-shallow beam (limit) → Width ≤ depth | |
| Measured as | Width = breadth perpendicular to span. Match to brick wall module (230 mm or 300 mm) to avoid offsets. Depth/width ratio of 1.5–2 keeps the beam stable in lateral buckling. |
| Source | IS 456 — Clause 26.5.1, 26.5.2 ✓ Verified |
68 related items across IS codes, knowledge articles, design rules, maps and tools
Beam width is fixed by two practical constraints — masonry module above and bar spacing inside. 230 mm is the default because it sits flush with a 9-inch brick wall; 300 mm comes from 230 mm rendered with two-side plaster. Width below 200 mm rarely passes IS 13920 ductile detailing for two-leg stirrups.
230 × 450, 230 × 500, 300 × 450, 300 × 600 — this set covers ~90% of Indian residential beams. Anything wider is usually a transfer beam or a balcony edge beam.