Cement mortar calculation in brick masonry

CALCULATION OF MATERIALS REQUIRED FOR BRICK WORK WITH STANDARD BRICKS FOR 10 CUM OF WORK.

BRICK:

Considering a wall 1½ brick thick, 30 cm nominal thickness of length 15 m and height of 5 m.

Ø Total Nominal Volume = 15m × 0.3m (30 cm) × 5m = 22.5 cum.

Normally for brickwork, mortar joint will be less than 1 cm (1 m), taking 1 cm mortar joint, the thickness of the wall will be 29 cm.

Ø Hence, the Actual Volume = 15m × 0.29m (29 cm) × 5m = 21.75 cum.

The Nominal size of a Standard Brick = 20 cm × 10 cm × 10 cm

Ø Then, the Volume of a Standard Brick of Nominal Size= 0.20m × 0.10m × 0.10m = 0.002 cum.

Ø Therefore, the Number of Standard Bricks for Actual Volume (21.75 cu m.) –

Ø Hence, Number of Brick required per cu m. (Nominal) –

Ø Considering 5% breakages, wastage, etc., then Number of Brick required per cu m. = 507 nos, this may be taken as 500 nos. per cum.

v For 10 cum. Of Brickwork (500x10) 5000 nos Brick are required.

MORTAR:

Ø Mortar requirement for Brickwork –

= (Total Actual Volume of Brickwork – Net Volume of Bricks)

= 21.75 – (10875×0.19×0.09×0.09)

= 21.75 – 16.737

= 5.013 cum.

Ø 15% extra Mortar considering for frog filling, for use of cut bricks, for bonding, for uniform joints, wastage etc., hence, the Total Volume the Mortar –

= Mortar requirement for Brickwork + (Mortar requirement for Brickwork × 15%)

= 5.013 + (5.013×15%)

= 5.765 cum.

Ø For dry volume increased by ¼ dry volume of Mortar –

= Total Volume the Mortar + (Total Volume the Mortar × ¼)

= 5.765 × (5.765 × ¼)

= 7.206 cum.

For 22.5 cum. of Brickwork, dry volume of mortar = 7.206 cum.

v For 10 cum of brickwork, Dry Volume of mortar = 7.206 × (10/22.5) = 3.203 cum.

Ø In practice, for cement mortar 3 cum. dry mortar and lime mortar 3.5 cum of dry mortar are taken for 10 cum. brickwork, an approximate 30% of total brickwork quantity may be taken for dry mortar.