How Much Sand and Cement Is Required for 100 Sq. Foot Plaster?

Plastering might not be the most glamorous aspect of construction, but it’s an essential part of creating a smooth and polished finish for your walls. Whether you’re renovating your home or building a new one, understanding how much sand and cement you need for plastering is crucial. 

Well, it will depend on the thickness of the plaster. For example, a 6 mm plaster thickness on a 100 sq ft wall requires 27 kg of cement and 2.56 cft sand. Whereas, 100 kg of cement is required for 23mm plaster.

To learn more, stay with me till the end and be the Quantity expert for your own work!

Amount of Sand and Cement Required for Different Types of Thickness for 100 Sq. Foot Plaster

Now that we’ve explored the different plaster thickness options, let’s get down to the numbers. Now, let’s do some simple calculations!

As the unit weight of Sand and Cement is in meters, for easier calculation, we have converted all units to meters.

Plastering Area = 100 x (0.3048)² [1 Foot² = 0.0929 m² ]

       =9.29 m² 

Mixing ratio = 1:4 (1 part of cement, 4 parts of sand)

Volume of plaster = Plastering Area x Thickness of plaster

For 6 mm = 9.29 x 0.006 = 0.056 m³ 

For 12 mm = 0.111 m³

For 18 mm = 0.167 m³

For 23 mm = 0.214 m³

As a rule of thumb, we will have to calculate including the wastage and others during the plastering work. For this, consider 20% in the volume of plaster. So, the new wet volume is,

For 6 mm = 0.056 + 20*0.056100 = 0.0672 m³ 

For 12 mm = 0.133 m³

For 18 mm = 0.2 m³

For 23 mm = 0.257 m³

#Quantity of Cement: 

The formula for determining the weight of Cement = Dry Volume of Plaster * Cement ratio of Sand and Cement Ratio X Density of Cement

For 6 mm plastering, 

cement required = 0.0672 * 1.35* 15 X 1440 kg/m³ [ Dry Vol of Plaster = wet vol * 1.35]

                                 = 26.0496 kg 27 kg of cement.

For 12 mm plastering, the quantity of cement = 49kg

For 18 mm plastering, the quantity of cement = 78 kg

For 23 mm plastering, the quantity of cement = 100 kg

#Quantity of Sand:

The formula for determining the quantity of Sand = Dry Volume of Plaster * Cement ratio of Sand and Cement Ratio * Sand ratio.

So, the quantity of sand for 

6 mm per ft is = 0.018144 X 4 = 0.0723 m³ = 2.56 ft³ [1 m³ = 35.3147 ft³]

For 12 mm =0.12 m³ = 4.23 ft³

For 18 mm = 0.216 m³ = 7.623 ft³

For 12 mm = 0.278 m³ = 9.8 ft³

These calculations are approximate and can vary based on factors like the quality of materials and the skill of the plasterer. Always consult with a professional or your local supplier to get precise measurements.

Types of Plaster Thickness

Before we dive into the specifics of calculating sand and cement, let’s first explore the different types of plaster thickness you may encounter during your construction process. The number of sand and cement bags can vary from different types of plaster thickness. 

A. Plaster Thickness of Internal Wall

6-mm Internal Plastering, Applied in One Coat

This type of plaster is ideal for a smooth and clean finish on your internal walls. It’s often used in areas where you want a minimalist and sleek look. But how much sand and cement will you need to get the job done.

12-mm Internal Plastering, Applied in One Coat

A slightly thicker plaster is required for those areas that might experience more wear and tear. This 12-mm plaster is perfect for adding durability to your internal walls. But let’s not forget to calculate the sand and cement quantities!

B. Plaster Thickness of Exterior Wall

18-mm External Rough or Smooth, Applied in two coats (1^st Coat 12-mm & 2^nd, 6-mm)

When it comes to exterior walls, you need plaster that can withstand the elements. This 18-mm plaster, applied in two coats, offers both protection and aesthetic appeal. Let’s find out how much sand and cement you’ll need for this job.

23-mm External rough plaster, Applied in two coats (1^st 8-mm & 2^nd 15-mm)

For an even sturdier finish on your exterior walls, the 23-mm plaster is the way to go. But again, we need to break down the sand and cement requirements to get it right.

Final Thoughts

Plastering isn’t just about slapping some mix on your walls; it’s an art that requires precision and a touch of creativity. Now that you know how much sand and cement you need for different plaster thicknesses, you’re better equipped to tackle your next construction or renovation project. Remember, a well-plastered wall not only enhances the aesthetics of your space but also adds to its longevity.