What Is Plaster | Plaster Ratio | History of Plastering | Requirements of Good Plaster

What Is Plaster _ Plaster Ratio _ History of Plastering _ Requirements of Good Plaster

What Is Plaster?

Plastering is the process of covering uneven surfaces and rough walls in the construction of houses and other structures with a plastic material known as Plaster, which is a mixture of cement or lime concrete and sand along with the required quantity of water.


Different Plastering Ratios of Cement Mortar Used

Mix Ratio of Mortar General Usage Recommended
1:3 As its a rich mortar mix, and it is used where external walls are prone to severe climatic conditions.
It is also used for repair works.
1:4 Used for Ceiling and external walls
1:5 Brickwork Mortar and for Internal Plaster
1:6  For Internal Plaster (fine sand is available)

Also, read: Difference Between Carpet Area and Built-up Area

Quantities Of Cement, Sand, And Water In Various Plaster Mix Ratio:

Area Plaster thickness Mix Ratio of Mortar Cement Sand Water
10 sqm 12 mm 1:3 49.37 kg 3.77 ft3 44lit
10 sqm 12 mm 1:4 39.29 kg 3.99 ft3 44lit
10 sqm 12 mm 1:5 32.54 kg 4.14 ft3 44lit
10 sqm 12 mm 1:6 27.8 kg 4.24 ft3 44lit

Requirements of Good Plaster

  • It should adhere to this background and should remain adhered to during all climatic changes.
  • It should be cheap and economical.
  • It should be hard and durable.
  • It should be possible to apply it during all weather conditions.
  • It should effectively check the penetration or entry of moisture from the surfaces.
  • It should possess good workability.

Also, read: What Is a Field Dry Density Test | Different Type of Field Density Tests

History of Plastering

A form of plastering was utilized by primitive civilizations, creating durable and weather-resistant structures using mud.

The Egyptian pyramids contain plasterwork comparable to that used today that remains hard and durable some 4,000 years later.

Greek artisans utilized Plaster, mainly to cover the exterior of temples but sometimes also interiors.

Through history, plaster ceilings became increasingly ornamental, with those during the Tudor period being particularly extravagant.

However, the use of Plaster for a means of demonstrating artistic skill and expression had waned from the 19th century, when imitation and mechanical reproduction displaced it as a creative medium.

But, Plaster is still very commonly used as a surface finish for interior ceilings, walls, and still sometimes for exterior walls.

Defects in Plastering

  • Flaking
  • Peeling
  • Popping
  • Cracks in Plastering
  • Uneven Plaster Surface`
  • The softness of the Plaster
  • Blistering of Plastered Surface
  • Rust Stains on Plastered Surface
  • Efflorescence on Plastered Surface

Also, read: Testing for Silt Content in Sand

Requirements of Good Plaster

To provide an even, clean, smooth, regular, and durable finished surface with improved appearance.

  • To conceal defective workmanship.
  • To preserve and protect the surface.
  • To provide a base for the decorative finish.
  • To cover up the use of inferior quality and porous materials of the masonry work

Type of Plaster

  • Gypsum Plaster
  • Lime Plaster
  • Cement Plaster
  • Clay Plaster
  • Heat-resistant Plaster
  • Water-Proof Plaster

Gypsum Plaster

This is widely used plaster materials that can be mined naturally or produced as a by-product.

Therefore, important gypsum plaster that’s employed as under coat finish coat and replaced cement broadly and lime.

Gypsum Plaster

Moreover, small expansion of gypsum is considered significant propertied that prevent cracks and shrinkages.

There are various types of gypsum plaster that are produced by heating gypsum to a specific degree, for example, anhydrous gypsum manufactured by heating gypsum up to 170 Co, hemihydrates gypsum produced by heating gypsum more than 170 Co.

Furthermore, depending on applications for ceilings or walls, gypsum plasters could be categorized like casting, undercoat, finish, one coat, and machine applied Plaster.

Also, read: 10 Best Cement Companies In India

Lime Plaster

This brings us to Lime Plaster, which, as stated earlier, is made up of sand, lime, and water. The lime in question is generally Non-Hydraulic Lime, which, of course, can also be called Lime Putty.

Lime Plaster

Incredibly, the use of Lime Plaster dates back as far as 7200BC, where statues sculpted in Lime Plaster were found buried in a pit in the archaeological site of a Ghazal in modern-day Jordan. This is the perfect example of just how durable Lime Plaster is as a building material.

Often products may be used as both a Lime Plaster and a Lime Render since the Lime Putty utilized is durable enough to withstand the weather conditions encountered in external use.

This is just one of many benefits of using lime Plaster or lime render. Though this on climate and geographical location. For any help choosing the right lime plaster, please do get in touch.

Also, read: What Is Plinth | What Is Plinth Protection | Purpose of Plinth Protection

Clay Plaster

Clay plaster is considered to be a more sustainable alternative to modern plasters, using a lower embodied energy than gypsum, lime, or cement-based plasters.

Clay Plaster

It’s available with fiber additives to increase its strength and in a range of natural colors. It is breathable and doesn’t need to be painted.

Heat-resistant Plaster

Heat-resistant plaster is a building material used for coating walls and chimney breasts and also for use as a fire barrier in ceilings.

Heat-resistant Plaster

Its purpose is to replace conventional gypsum plasters in cases where the temperature may get too high for gypsum plaster to stay on the ceiling or wall.

Water-Proof Plaster

Waterproof plaster is needed for the protection of the masonry wall from the ingress of moisture and thus eliminating or reducing dampness of the wall.

Waterproof Plaster

The plaster is made from sand and cement mix 1: 2. Pulverized alum is added at the rate of 12 kg per cubic meter of sand.

Softsoap in the rate of 75 gms per liter is added from the water for mixing. Alum and soap react chemically and seal the pores from the plaster.

Short Note

Plaster Mix Ratio

Mix cement and sand in the ratio of 1:6 (1 cement:6 sand) for inner plastering of bricks. And for outer plastering mix it in the ratio of 1:4. On a brick wall never do plastering of thickness more than 12 or 15mm. At one go, avoid plastering of more than 12mm thickness.

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