In this civil engineering article, one will learn how to work out the quantity of cement and sand in 100 ft² plastering work for a wall. The thickness of the plaster is ½ inches or 12 mm. The mix ratio of plaster is 1:6 i.e. 1 part cement and 6 part sand.

The calculation is done in the following way:-

Area of plaster = 100 ft²

We know 1 ft² = 0.0929

So, 100 ft² = 100 x 0.0929 = 9.29 m²

The thickness of plaster = 12 mm or 0.012 m (divide with 1000)

Initially, you have to work out the volume of plaster as follow:-

So, Volume = Area x Thickness

After putting the values, we get

Volume = 9.29 m² x 0.012 m = 0.11 m³

Now the wastage and extra quantity of plaster should be added with the volume of plaster.

So, 0.11 m³ + 20%

Or 0.11 + (20/100 + 0.11) = 0.13 m³

But, the above value is for wet volume (as moisture is included in it and the volume becomes low) and it should be converted to dry volume.

So, dry volume = 0.13 x 1.35 (multiply with 1.35 for conversion) = 0.17 m³

The quantity of cement will be calculated with the following formula:-

So, cement = Dry volume x ratio of cement / sum of ratio x density of cement

After putting the value, we get the following result:-

Cement = 0.17 x 1 / 5 = 0.03 m³ (sum of ratio = 1+4 = 5)

0.03 x 1440 = 50 Kg (rounded off) [ density of cement = 1440 kg m³]

We know, the weight of 1 bag cement = 50 kg

So, here, one bag cement will be required.

The quantity of sand will be calculated with the following formula:-

Sand = Volume of cement x Sand ratio

After putting the value, we get the following result:-

Sand = 0.03 x 4 = 0.12 m³

As we know, 1 m³ = 35.314 square feet

So, 0.12 m³ x 35.314 = 4.23 cft

So, sand will be required = 4.23 cft