How to read a structural drawing schedule
Published 16 Aug 2026
An architectural drawing shows you what the building looks like. A structural drawing tells you what it costs, and most of that information is not drawn — it is written, in compressed notation, in tables at the edge of the sheet.
If you can read those tables, you can measure concrete and steel instead of guessing at them. This guide covers the four schedules you will encounter and what to pull from each.
Column schedule
The most information-dense table on the sheet. A typical row:
C1 — 230 × 450 — 8-16φ — 8φ @ 150 c/c — GL to +3.00
| Field | Meaning |
|---|---|
C1 | Column mark. Every column on the plan tagged C1 has these properties |
230 × 450 | Cross-section in mm — width × depth |
8-16φ | Eight main bars of 16mm diameter. φ (or Ø, or T, or #) means diameter |
8φ @ 150 c/c | Lateral ties of 8mm at 150mm centre-to-centre spacing |
GL to +3.00 | The level range this applies over — ground level to 3.0m |
What to extract: section area × height gives concrete volume per column. Count the C1 tags on the plan for the multiplier. Main bar count and diameter plus tie spacing feed the steel calculation.
The trap: the level range. A column often changes section or reinforcement between floors, appearing as two or more rows for the same mark. Reading only the first row and multiplying by full building height gets both the concrete and the steel wrong.
Also watch: whether ties are specified at closer spacing near the ends. Many
schedules note something like 8φ @ 100 c/c for 600 from each end, 150 c/c elsewhere.
That changes the tie count.
Beam schedule
B1 — 230 × 450 — Top: 2-12φ — Bot: 3-16φ — Str: 8φ @ 150 c/c
| Field | Meaning |
|---|---|
230 × 450 | Width × overall depth in mm |
Top: 2-12φ | Two 12mm bars at the top face |
Bot: 3-16φ | Three 16mm bars at the bottom face |
Str: 8φ @ 150 | Stirrups of 8mm at 150mm centres |
Top and bottom differ because a beam is in tension at the bottom at midspan and at the top
over supports. Some schedules split further —
Top: 2-12φ through + 2-16φ extra at supports — and the extra bars are shorter,
running only a fraction of the span. Missing them understates steel; treating them as
full-length overstates it.
Overall depth versus clear depth. The scheduled depth is usually overall, including the slab thickness where the beam is monolithic with it. For concrete volume, the beam below the slab is what gets measured as beam — the rest is already in the slab quantity. Billing full depth double-counts the overlap.
Span. Rarely in the schedule; take it from the plan. Clear span between column faces, not centre-to-centre, unless the schedule says otherwise.
Footing schedule
F1 — 1500 × 1500 × 450 — 12φ @ 150 c/c both ways — Depth 1.8m
| Field | Meaning |
|---|---|
1500 × 1500 | Plan dimensions in mm |
450 | Thickness |
12φ @ 150 c/c both ways | A mesh of 12mm bars at 150 centres in both directions |
Depth 1.8m | Founding depth below ground level |
What to extract: footing volume for RCC, and the PCC bed beneath it — usually 75 or 100mm thick and extending 50 to 150mm beyond the footing on each side, which needs checking rather than assuming.
The excavation trap. Excavation volume is not the footing volume. The pit is larger than the footing to allow working space, and it runs from ground level to founding depth. Excavation depth is measured from ground level, not from plinth level — including plinth height here is one of the most common overcounts in manual estimates.
Footing type matters more than any other single assumption. Isolated, combined, strip and raft footings differ enormously in concrete and steel for the same building. If the schedule shows a raft and your estimate assumes isolated footings, nothing downstream is recoverable.
Slab notes
Slabs rarely get a table. Reinforcement appears as notes on the plan:
Slab 125 thick — 10φ @ 150 c/c short span — 8φ @ 200 c/c long span — Extra top 10φ @ 150 over supports
Read this as: main bars run the short direction at 150mm centres, distribution bars the long direction at 200mm centres, plus additional top steel over continuous supports.
One-way versus two-way changes the reinforcement pattern. If the long span is more than about twice the short span, the slab spans one way and the long-direction bars are nominal distribution steel. If the ratio is under two, it is two-way and both directions carry load. The schedule usually implies this through the bar sizes rather than stating it.
Extra top steel over supports is easy to miss and can be 15 to 20 percent of slab steel on a continuous slab.
Notation you will meet
| Symbol | Meaning |
|---|---|
φ Ø T # | Bar diameter, all used interchangeably |
c/c | Centre to centre spacing |
@ | At the following spacing |
nos | Number of |
GL | Ground level |
FFL | Finished floor level |
+3.00 | Level in metres above datum |
Fe500D | Steel grade — 500 MPa yield, D denoting improved ductility |
M20 M25 | Concrete grade — characteristic strength in MPa |
Grade matters for pricing. M25 costs more per cubic metre than M20, and Fe550 more per kilogram than Fe500. A schedule specifying different grades for different members and an estimate applying one rate throughout is a real error, not a simplification.
A reading order that works
- General notes first. Concrete grades, steel grade, cover values, and any project-specific conventions. These govern everything else and are usually ignored.
- Footing schedule. Establishes foundation type, which fixes the largest single unknown.
- Column schedule with the plan. Count each mark, note level ranges.
- Beam schedule with the framing plan. Take spans off the plan.
- Slab notes. Thickness, reinforcement, extra steel.
- Reconcile against the architectural plan. Column positions should match, beam lines should sit over walls or explicitly not. Where they disagree, ask before measuring.
That last step catches more errors than any other. Structural and architectural drawings are revised at different times, and a mismatch means one of them is out of date.
For turning what you read into steel quantity, see how to calculate steel quantity from structural drawings and the bar bending schedule format. For the wider measurement sequence, see how to make a BOQ from architectural drawings.
Frequently asked questions
What does 8-16φ mean in a column schedule?
Eight main reinforcement bars of 16mm diameter. The φ symbol denotes diameter and may also appear as Ø, T or #. It is written this way as count-hyphen-diameter throughout Indian structural drawings.
What does c/c mean on a structural drawing?
Centre to centre — the spacing between the centrelines of adjacent bars. Stirrups at 150 c/c are spaced 150mm apart measured centre to centre, not clear gap.
How do I know if a slab is one-way or two-way?
Compare the spans. If the longer span exceeds roughly twice the shorter, the slab spans one way and the long-direction bars are distribution steel only. Below that ratio it is two-way and both directions are structural.
Can I estimate concrete without a structural drawing?
Only by thumb rule, which carries wide variance. The structural drawing is what lets you measure real column sections, actual beam spans and scheduled footing sizes rather than assuming them.
What is the difference between overall depth and clear depth of a beam?
Overall depth includes the slab thickness where the beam is cast monolithically with it; clear depth is the portion hanging below the slab soffit. For concrete measurement, the portion already counted in the slab quantity should not be measured again as beam.