Brickwork estimating: number of bricks, mortar and wastage

Brickwork remains the most common walling in Bangladesh. Its estimate has two parts — bricks and mortar — and one discipline: deducting openings.

The standard brick

The common first-class brick measures about 9½" × 4½" × 2¾" (240 × 115 × 70 mm). With a 10 mm (⅜") mortar joint, the nominal size becomes about 10" × 5" × 3".

Bricks per unit volume

• Volume of one nominal brick = 10 × 5 × 3 = 150 in³
• 1 cft = 1,728 in³ → 11.5 bricks per cft
• 1 cum ≈ 35.31 cft → about 406 bricks per cum (by the metric nominal 250 × 125 × 75 mm, about 427)

Add 3–5 % breakage and wastage.

Mortar

The mortar fills the joints and the frog. A practical figure is 0.30 cft of dry mortar per cft of brickwork (wet mortar about 0.22–0.25 cft, × 1.33 dry factor).

For 1:4 mortar (parts = 5):

• per 100 cft of brickwork: dry mortar = 30 cft
• cement = 30 / 5 = 6 cft = 4.8 bags
• sand = 24 cft

For 1:6 (parts = 7): cement = 4.3 cft = 3.4 bags, sand = 25.7 cft.

Measuring walls

1. Measure each wall's length along its centre line (avoid double counting corners).
2. Multiply by height and thickness: 10" (250 mm) and 5" (125 mm) walls are typical.
3. Deduct doors, windows, lintels, beams and columns that interrupt the wall.

Worked example

A 10" wall, 40 ft long and 10 ft high, with two 3' × 7' doors and three 4' × 4' windows:

• Gross = 40 × 10 × 0.833 = 333.3 cft
• Doors = 2 × 3 × 7 × 0.833 = 35.0 cft
• Windows = 3 × 4 × 4 × 0.833 = 40.0 cft
• Net = 258.3 cft → 2,970 bricks + 4 % = 3,090 bricks; mortar 77.5 cft dry; at 1:4, 12.4 bags of cement

Half-brick walls

5" walls are usually measured by area (sft or sqm) in the BOQ, with bricks and mortar per sft derived the same way.

In EstiMatrix

Use − Add deduction rows for openings; they turn red and subtract automatically. The material requisition sums bricks, cement and sand from every brickwork analysis.