Methods of Measurement
The take-off — long-wall/short-wall, centre-line, and the IS 1200 rules.
In the detailed estimate every element is measured from the drawings as No. × Length × Breadth × Height on a ruled sheet. The two classic ways of getting wall lengths — the long-wall/short-wall method (out-to-out and in-to-in) and the centre-line method (one total length × each layer) — must give identical answers. Learn both, the all-important centre-line junction correction at cross-walls, the IS 1200 deduction rules, and why a wrong unit or a missed deduction corrupts the estimate. Try the centre-line estimator.
Learning objectives
By the end of this lesson, you will be able to — mapped to the course outcomes for Estimation and Specification:
Take off quantities on a measurement sheet as No. × L × B × H.
Compute quantities by the long-wall/short-wall and centre-line methods.
Apply the centre-line junction correction at cross-walls.
Apply the IS 1200 deduction rules for openings in brickwork and plaster.
The two measurement methods
The centre-line method is one length × each layer; long-wall/short-wall measures out-to-out and in-to-in — and both must agree.[1]
No. × L × B × H
Every element is measured from the drawings on a ruled sheet — columns for Item, No., Length, Breadth, Height/Depth, Quantity, Remarks. Quantity = N × L × B × D; sub-totals carry to the abstract; deductions are negative lines under the same item; always note the drawing reference. Work systematically, substructure upward.[1, 4]
Estimate a room live
Set a room's internal size, wall thickness and excavation section and watch the centre-line length, earthwork, PCC and brickwork compute.
Centre-line estimator · a single room
15.20
m centre-line
12.31
m³ earthwork
2.74
m³ PCC bed
12.62
m³ brickwork (net)
Centre-line length = 2 × ((L + t) + (B + t)) = 15.20 m. A simple rectangle (four L-corners) needs no junction deduction; brickwork is the gross 13.68 m³ minus 1.06 m³ of openings.
Each layer = centre-line length × that layer's breadth × depth. Add a cross-wall and you would deduct one breadth per junction.
The IS 1200 rules
Deduct full openings in brickwork (ignore ≤0.1 m²), one face for plaster (0.5–3 m²), and one breadth per cross-junction in the centre-line method.[2]
Full openings, ignore the tiny
In brickwork/masonry, door and window openings are deducted FULL size (width × height × wall thickness); small openings ≤ 0.1 m² are NOT deducted, and a lintel's bearing in the wall is not separately deducted. Earthwork, concrete and masonry are all measured in m³.[2]
At a glance
| Aspect | Long/short-wall | Centre-line |
|---|---|---|
| Length basis | Long/short-wall: out-to-out + in-to-in per layer | Centre-line: one total length |
| Speed | Long/short-wall: slower, more lines | Centre-line: faster, one line per layer |
| Junction correction | Long/short: implicit in in-to-in lengths | Centre-line: subtract one breadth per junction |
| Best for | Long/short: irregular / varying thickness | Centre-line: uniform-thickness rectangular plans |
| Must they agree? | Yes — same building | Yes — identical quantities |
Key terms
Extracting and measuring each item's quantity from the drawings onto a sheet.
Length measured to the outer faces of the walls (long walls).
Length measured between the inner faces of the walls (short walls).
The running length along the centres of the walls.
Deduction of one layer-breadth per cross-junction in the centre-line method.
Horizontal haul / vertical raise of material beyond the free limits.
Studio task
For a room internal 4.0 × 3.0 m with 0.30 m walls, take off the earthwork, PCC, brick footing and superstructure brickwork by BOTH the centre-line and the long-wall/short-wall methods and show they agree. Deduct one door (1.0 × 2.1) and one window (1.2 × 1.2) from the brickwork. Then add an internal cross-wall and apply the junction correction.
Self-assessment
1. In the centre-line method, at each cross-wall T-junction you must —
2. In brickwork, an opening of 0.08 m² is —
3. The long wall is measured ___ and the short wall ___.
Recap
References & further reading
- [1]B.N. Dutta, Estimating and Costing in Civil Engineering (long-wall/short-wall & centre-line examples).
- [2]BIS, IS 1200 (Parts 1–28) — Method of Measurement (Part 1 earthwork, Part 3 brickwork, Part 12 plastering).
- [3]M. Chakraborti, Estimating, Costing, Specification & Valuation (measurement sheets & deductions).
- [4]S.C. Rangwala, Estimating and Costing (measurement methods).
- [5]CPWD Analysis of Rates (lead/lift conventions).
Further reading
- B.N. Dutta — Estimating and Costing in Civil Engineering.
- BIS — IS 1200 (Method of Measurement).
- S.C. Rangwala — Estimating and Costing.
Sources gathered and fact-checked June 2026. Published values vary by source, sample and method — treat as indicative and confirm against the cited standard before structural use.