How to Calculate Quantity of Material For Plastering

How to Calculate Quantity of Material For Plastering

The term plastering is used to describe the thin mortar covering that is applied on the surface of the wall and ceiling. The plastering removes the unevenness of the surface and sometimes used to develop decorative effects. Today in this article we will learn how to calculate the quantity of material for plaster.

Calculation of quantity of material for 12 mm thick plaster of ratio 1: 6 (1 Cement:6 Sand) in the wall for 100 mm2

The volume of mortar  =  Area × Thickness
=    100   × 0.012
=     1.2

Adding 30% to fill up joints, uneven surface etc

Wet Volume of Mortar =  1.2 + 0.36
=     1.56 Cum

Increasing 25% for dry volume

Total Dry Volume       =   1.56 + 0.39
=    1.95
=    2 Cum (say)
Quantity of Cement  =    2/(1+6) × 1             (1 Ratio of cement)
=  0.30 Cum
In Kg                           =   0.30 × 1440           (Density of cement = 1440 kg/m3)
=    432 Kg
In Bags                        =    8.64 bags
Quantity of  Sand      =    2/(1+6) × 6              (6 Ratio of sand)
=     1.80 Cum
In Cubic Feet              =      63.558 cft               (1 Cum = 35.31 cft)

Water Required        =    Cement quantity in  Kg × 0.5        (water cement ratio = 0.5)
=        432 × 0.5
=         216 Litres

Alternative Method

Quantity of Sand    =  Cement bags × Sand ratio ×1.226  (Volume of one bag cement = 1.226 cft)
=          8.64  ×  6  ×  1.226
=             63.55 cft

Similarly, The quantity of materials for other proportions may be calculated.

Material For 20 mm thick Plastering in the wall for 100 sqm

As the thickness of plaster is more 20% of mortar may be taken to fill up the joints, unevenness etc.

The Quantity of wet Mortar  =  100 × 0.02 + 20%
=  2 + 0.4
=    2.4 cu m
Increasing 25% for dry volume of mortar

Dry Volume of Mortar  =  2.40 + 0.60
=        3.00 cu m
The quantities each material of mortar may be found by the usual method as discussed above.

Rich Mortar

For rich mortar plastering, the quantities of material will be less as the cement will be in excess than the voids in sand and the reduction in the volume of dry mortar will be less.

Ceiling Plastering 12 mm thick for 100 sqm

For plastering in RCC ceiling, the unevenness of surface will be less and 20% extra mortar may be taken to get even surface.

The quantity of wet mortar  =  100 × 0.12 + 20%
=   1.2 + 1.4
=     2.6 cu m
Increasing 25% for dry volume

The dry volume of mortar    =   1.44 + 0.36
=       1.80
The quantities each material of mortar may be found by the usual method as discussed above.

For 6 mm thick plastering in RCC, the quantity of dry mortar may be taken as 1.00 cu m.

General Notes

The ratio of Cement Mortar for Wall Plastering             =        1:6
The ratio of Cement Mortar for Ceiling Plastering         =        1:4
The thickness of the Internal Wall Plastering                  =        12 to 15 mm
The thickness of the External Wall Plastering                 =        15 to 20 mm
The thickness Plastering on Concrete Face                     =         6 to 8 mm