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.
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
- 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
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.
Also, read: 10 Best Cement Companies In India
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 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 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.
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.