Cement and sand for 200 m² plastering numerical

Given: plastering area $= 200\ \text{m}^2$; thickness $= 10$ mm; mix 1:5 (cement : sand).

Step 1: Wet volume of mortar

$$200 \times 0.01 = 2\ \text{m}^3$$

Step 2: Dry volume (add 27% for dry bulk, voids in sand and wastage)

$$2 \times 1.27 = 2.54\ \text{m}^3$$

Step 3: Cement and sand (sum of ratio $= 6$)

$$\text{Cement} = \frac{2.54}{6} = 0.423\ \text{m}^3 \approx 12.2\ \text{bags (0.0347 m}^3\text{ per bag)}$$ $$\text{Sand} = \frac{5}{6} \times 2.54 = 2.117\ \text{m}^3$$

Answer: Cement = 0.423 m³ (about 12.2 bags of 50 kg = 610 kg); sand = 2.117 m³.