To calculate quantity of materials required for plastering we need following data along with area plastering:

- Thickness of plaster (i.e., 6 mm, 12 mm & 15 mm)
- Mix ratio plaster (i.e., 1:3, 1:4, 1:5 & 1:6)

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 ft^2 (9.2903 m^2)

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 = 9.2903 x 0.012=0.1115 m³

**Add 20% extra Quantity for Filling of joints, Depressions & Wastage**

∴Volume of plaster = 0.1115 + [ (20×0.1115) /100 ] =0.1338 m³

**Dry volume of plaster = Wet volume x 1.35**

Dry Volume = 0.1338 x 1.35 = 0.1806 m³

**Step 3:- Quantity of Cement**

**Quantity of Cement = (Dry Volume of plaster x Cement ratio) / (Sum of the ratio)**

Quantity of cement = (0.1806 x 1) /(1+4)= **0.0361 m³**

**∵ Density of Cement = 1440 kg/m³**

Weight of Cement = 1440 x 0.0361 = **52.020 Kg**

**∵ 1 bag of cement contains 50 kg of cement**

Number of bags = 52.020 Kg/50 = **1.040 No’s**

**Step 4:- Quantity of Sand**

*∵ Cement : Sand :: 1:4*

**Quantity of Sand = Quantity of Cement x 4**

∴ Quantity of Sand = 0.0361 m³ x 4 = **0.1444 m³**

**∵ 1 m³=35.3147 Cubic Feet (CFT)**

Quantity of sand = 0.1444 x 35.3147 = **5.0994 CFT**

**∵ 1 brass = 100 CFT**

Sand = 5.0994 /100 = **0.0509 Brass**

**∵ Density of sand = 1920 kg/m³**

Weight of sand = 0.1444 x 1920 = **277.248 kg**

**∵ 1 tonne = 1000 kg**

Weight of sand in Tonne = 277.248 /1000 =**0.2772 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 (52.020+ 277.248 ) = 65.85 kg = 65.8536 **Liters**

**Watch the video given in the link below, for better understanding and detailed explanation**

**How to calculate Quantity of Cement Sand & Water in plaster of 1:4 ratio**