In order to calculate the required quantity of cement, sand and water for plastering we have to follow the following 5 simple steps.
Step 1:- Assumptions
Area of Plaster = 100 m²
Thickness of plaster = 12 mm =0.012 m
Mix Ratio → 1:4
Step 2:- Volume of Plaster
∵ Volume of plaster = Area of plaster x Thickness of plaster
Volume of plaster = 100 x 0.012=1.2m³
Add 20% extra Quantity for Filling of joints, Depressions & Wastage
∴Volume of plaster = 1.2 + [ (20×1.2) /100 ] =1.2 + 0.24 =1.44 m³
Dry volume of plaster = Wet volume x 1.35
Dry Volume = 1.44 x 1.35m = 1.944 m³
Step3:- Quantity of Cement
Quantity of Cement = (Dry Volume of plaster x Cement ratio) / (Sum of the ratio)
Quantity of cement = (1.944 x 1) /(1+4)= 0.3888 m³
∵ Density of Cement = 1440kg/m³
Weight of Cement = 1440 x 0.3888 = 559.872 Kg
∵ 1 bag of cement contains 50 kg of cement
Number of bags = 559.872 Kg/50 = 11.2 No’s
Step 4:- Quantity of Sand
∵ Cement : Sand :: 1:4
Quantity of Sand = Quantity of Cement x 4
∴ Quantity of Sand = 0.3888 m³ x 4 = 1.5552 m³
∵ 1 m³=35.3147 Cubic Feet (CFT)
Quantity of sand = 1.5552 x 35.3147 = 54.921 CFT
∵ 1 brass = 100 CFT
Sand = 54.921 /100 =0.54921 Brass
∵ Density of sand = 1920 kg/m³
Weight of sand = 1.5552 x 1920 = 2985.98 kg
∵ 1 tonne = 1000 kg
Weight of sand in Tonne = 2985.98 /1000 =2.985 Tonne
Step 5:- Quantity of water
Quantity of water equals to 20% Total Dry material (cement & sand)
Quantity of water = 0.20 x (Weight of cement + Weight of sand )
∴ Quantity of water = 0.20 x (559.872+ 2985.98) = 709.2 kg = 709.2 Litre
watch the below video for better understanding and detailed explanation & To know the Quantity of cement, sand & water for 6 mm, 12 mm and 15 mm thickness of plastering
How to calculate Quantity of Cement Sand & Water in plaster of 1:4 ratio
