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

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

Requirements of Good Plaster

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

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

However, the use of Plaster as 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, and walls, and still sometimes for exterior walls.

Defects in Plastering

1. Flaking
2. Peeling
3. Popping
4. Cracks in Plastering
5. Uneven Plaster Surface`
6. The softness of the Plaster
7. Blistering of Plastered Surface
8. Rust Stains on Plastered Surface
9. Efflorescence on Plastered Surface

Requirements of Good Plaster

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

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

Type of Plaster

1. Gypsum Plaster
2. Lime Plaster
3. Cement Plaster
4. Clay Plaster
5. Heat-resistant Plaster
6. 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. 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.

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.

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.

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. 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. 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. 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.

Frequently Asked Questions (FAQ):

What Is Plaster?

Plaster is a construction material used to cover uneven surfaces and rough walls. It is a mixture of cement or lime, sand, and water, applied to surfaces to create a smooth and even finish.

What Are the Different Types of Plaster?

The main types of plaster include:

1. Gypsum Plaster: Used for its ease of application and ability to prevent cracks and shrinkage.
2. Lime Plaster: Known for its durability and historical use; made from lime, sand, and water.
3. Cement Plaster: Commonly used for its strength and durability, particularly in external walls.
4. Clay Plaster: A sustainable option that is breathable and often used in eco-friendly construction.
5. Heat-Resistant Plaster: Designed for high-temperature environments, such as around chimneys.
6. Water-Proof Plaster: Used to protect walls from moisture ingress and reduce dampness.

What Are the Recommended Mix Ratios for Plaster?

Common mix ratios for plaster are:

1. 1:3: For severe climatic conditions and repair works.
2. 1:4: For ceilings and external walls.
3. 1:5: For brickwork mortar and internal plaster.
4. 1:6: For fine internal plaster.

How Do You Calculate the Quantities of Materials Needed for Plastering?

The quantities of cement, sand, and water vary based on the mix ratio and the thickness of the plaster. For example, for a 10 sqm area with a 12 mm thickness, the quantities are:

1. 1:3 Mix: 49.37 kg of cement, 3.77 ft³ of sand, and 44 liters of water.
2. 1:4 Mix: 39.29 kg of cement, 3.99 ft³ of sand, and 44 liters of water.
3. 1:5 Mix: 32.54 kg of cement, 4.14 ft³ of sand, and 44 liters of water.
4. 1:6 Mix: 27.8 kg of cement, 4.24 ft³ of sand, and 44 liters of water.

What Are the Requirements of Good Plaster?

Good plaster should:

1. Adhere well to the background and remain adhered through various climatic changes.
2. Be economical and durable.
3. Be applicable in all weather conditions.
4. Effectively prevent moisture penetration.
5. Have good workability.

What Are Common Defects in Plastering?

Common plastering defects include:

1. Flaking and peeling
2. Popping
3. Cracks
4. Uneven surface
5. Softness
6. Blistering
7. Rust stains
8. Efflorescence

How Can Defects in Plastering Be Prevented or Fixed?

To prevent defects, ensure proper surface preparation, mix ratios, and application techniques. For existing defects, repair methods vary depending on the issue, such as re-plastering affected areas or treating underlying causes like moisture ingress.

What Is the Historical Significance of Plastering?

Plastering has been used since ancient times, with evidence found in Egyptian pyramids and Greek temples. Historically, it has been used for both practical and artistic purposes, although its use as an art medium has diminished since the 19th century.

What Is the Difference Between Plaster and Render?

Plaster is typically used for interior surfaces to create a smooth finish, while render is used for exterior walls and often includes additional additives for durability and weather resistance.

How Should Plaster Be Maintained?How Should Plaster Be Maintained?

Plaster should be regularly inspected for signs of wear or damage. Proper maintenance includes repairing any defects promptly and ensuring that the plastered surfaces are protected from harsh weather conditions.