How to Calculate Cement and Sand Required for Cement Mortar Plastering

Plastering on the walls for the purpose of to remove surface undulations and , maintain the line level of the alignment.It also acts as a protective surface for external walls against the leaakages,seepages etc. The types of plaster commonly known as Cement plaster, Gypsum plaster and Lime plaster etc.which are commonly used plastering materials in the residential constructions. Cement plaster is made by mixing cement and sand in the proportions required. Cement plaster is applied to both interior and exterior walls to give them a smooth surface.


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Commonly used Cement Mortar ratio for Plastering:

Mix Ratio of Mortar General Usage Recommended

1:3 Very rich mortar mix. Not recommended for general usage at sites. Can act a s a repair mortar with a waterproofing/bonding agent

1:4 For External Plaster and for ceiling plaster) ( in external plaster of 20 mm thick base coat of 12 mm done with 1:4 and remaining mm done with 1:3

1:5 Brickwork Mortar and for Internal plaster (If sand is not fine Fineness Modulas > 3)

1:6 For Internal Plaster (if fine sand is available)

How to Calculate Cement and Sand Required for Cement Plastering:

To arrive at the quantities of Cement, Sand and Water required for Plastering work, we need to have a clarity on what parameters do these quantities depend.

Volume of Plaster required: Volume of Plaster can be determined by multiplying the area of plastering nultiplied by the thickness. Generally it is 12 mm.

Mix Ratio of Plaster: Mix ratio mean the ratio of Volume of Cement to the Sand used in the proportionate of the mixture. Plaster of mix ratio 1:4 mean that it contains one part of cement and 4 parts of sand by volume. Since the amount of cement and sand changes with the change in the mix ratio, it is one of the most important factors in determining the quantities.

Quantities of Cement, Sand and Water in Various Mix Ratio of Plaster:

Area (Sqm)) Mix proportion Cement (in Kgs) Sand (In cft) Water (in Kgs)

10 1:3 49.37 3.77 44

10 1:4 39.29 3.99 44

10 1:5 32.54 4.14 44

10 1:6 27.80 4.24 44

The above calculation done on the basis of plaster thickness 12 mm. accprdingly ypu can calculate for various other thickness.Wastage not considered in the calculation. You can consider the wastage According to your site quality control. Generally we consider 5% wastage

Tip: Ready Made plaster (40 kg) are also available in market. They are ready to use with only an addition of water. The other details you can obtain from the manufacturer..