UPSC » UPSC CSE Study Materials » Chemistry » Knowing More On Gypsum Plaster

Knowing More On Gypsum Plaster

Learn about the outstanding characteristics of Gypsum and why it has been used in construction for ages.

Gypsum plaster is a popular choice for walls, ceilings, and floors because it is easy to work with, has a long-lasting finish, and is relatively inexpensive. Gypsum plaster is a type of plaster made from Gypsum. It is a soft, lightweight mineral found in many places worldwide.

Gypsum plaster can paint or stain to match any décor. They can also use it in place of wood or other traditional building materials. Gypsum plaster is composed of two parts: an adhesive and drywall. The bond binds the Gypsum to the surface that it will be covering. The drywall is then applied over the glue and creates a smooth, finished surface.

Gypsum Plaster’s History

The invention of gypsum plaster is not new. Because of its outstanding characteristics, it has been used in construction for ages because of its exceptional features. The ancient Egyptians consumed it to plaster the Cheops Pyramid. The use of gypsum plaster as an inside plaster in Egypt’s Giza pyramid demonstrates its longevity and performance.

Gypsum plaster of Paris is a versatile product that can be used in various applications. It is easy to install and has a long-lasting finish.

How Is Gypsum Plaster Prepared?

Gypsum is a lightweight mineral found in thick beds or layers in river bottoms, coastlines, deltas, hot springs, and lagoons where there is calcium and sulphate-rich water. Sulphur forms a sulphate when water evaporates, and sulphur comes into contact with oxygen (SO4). 

Gypsum (CaSO4.2H2O) is formed when sulphate combines with calcium and water.

Gypsum is a mineral that can be found as crystals or deposits in river beds worldwide. Gypsum plasters are made by grinding the Gypsum to a fine powder and heating it to high temperatures.

Gypsum Plaster Thickness

It can be applied in thicknesses ranging from 6 to 20mm. The undercoat of the plaster is frequently 11mm thick for walls and 8mm dense for gypsum ceiling, while the texture coat plaster is 2mm thick. 

A minimum thickness of 6mm gypsum plaster is advised to avoid cracks. If a wall requires more than 20mm of an application built up, a dash coat of cement sand plaster for a thickness of 8-12mm is put first, followed by gypsum plaster for the remaining thickness of not less than 6mm to provide a smooth finish.

Storage Of Gypsum

The setting time and strength of Gypsum plaster of Paris are significantly reduced when exposed to moisture. As a result, gypsum bags must be stored on an elevated, dry platform made of wood, brick, or concrete. It has a shelf life of 3-4 months from the date of manufacture. If stored properly at the right temperature and humidity, its shelf life can be extended to 6 months.

Types Of Gypsum Plaster

Based on the amount of valuable heat during the manufacturing progression, there are two varieties of gypsum plasters.

  • Anhydrite gypsum plaster is made by heating gypsum to 1700 degrees Celsius.
  • Hemihydrate gypsum plaster is made by heating gypsum to above 1700 degrees Celsius.

How Is Gypsum Plaster Applied?

The gypsum plaster is combined with water during application—some helpful hints for Gypsum plaster of Paris.

Before putting the plaster

Make sure that any cracks, holes, or seams are repaired. Before plastering, dust must also be eliminated. It may be challenging to obtain a smooth, crack-free, glossy finish without sufficient surface preparation.

Mixing with water

When mixing with water, always add the gypsum plaster to the water, not the other way around. It enhances the application’s consistency and helps prevent lumps from forming.

Always mix thoroughly

Do not overmix the ingredients. The best time to mix is 1-2 minutes. Complete the mixing in less than 2 minutes and more than a minute. You may not be able to achieve the proper consistency and smoothness of the finish if you overmix

The plaster. On the other hand, undermixing causes the plaster to separate and peel away from the surface.

Do not soak the plaster in water for too long.

The plaster may begin to settle and harden as a result of this.

Don’t use contaminated tools

Using soiled buckets, contaminated tools, contaminated water, or soiled drills can impact the quality of the plastering job. At every stage of the plastering process, clean the equipment, tools, and machinery.

Conclusion

Water should not be mixed at extreme temperatures, either cold or hot. If you use hot water, the plaster may solidify simultaneously, making it challenging to obtain the ideal smoothness. If you use icy water, on the other hand, you may have to invest in a lot of work to get the plaster to mix correctly. As a result, use room temperature water.

faq

Frequently asked questions

Get answers to the most common queries related to the UPSC Examination Preparation.

What is gypsum plaster?

Ans. Gypsum Plaster is an ancient and commonly used last method. It is used to give a wall’s block or ...Read full

What are the two types of Gypsum plaster?

Ans. Hemihydrate gypsum plaster is made by heating gypsum to above 1700 degrees Celsius. Anhydrite gypsum plaster is...Read full

What are the advantages of Gypsum?

Ans. It is simple to apply and mould into various shapes for decorative purposes; the setting time of gypsum plaste...Read full

What are the disadvantages of Gypsum?

Ans. Gypsum plaster of Paris is more expensive than cement plaster for the same thickness. Gypsum plaster would be more cost-effective in locations...Read full

What are the characteristics of Gypsum?

Ans. Gypsum is lightweight, and using it for plastering does not add to the structural strain on the building. Unlik...Read full