Uses of Gypsum Plaster in Construction

One of the oldest and most common finishing procedures is plastering. It is used to give the wall’s block or brick masonry a smooth, aesthetically beautiful surface. Bricks and stones are shielded from the elements by plastering, which also improves their visual appeal. Different types of plasters are utilised in different works depending on the desired finishes, components, popularity, and required proportion. Cement plaster, lime plaster, clay plaster, mud plaster, gypsum plaster, and other types of plaster are all available on the market.

Gypsum plaster has become more common during the past few decades and has mostly supplanted lime and cement plasters.

What is Gypsum Plaster?

Calcium sulphate and water combine to form the mineral gypsum. The name of the chemical is calcium sulphate dihydrate. Gypsum has a chalk-like texture  and is lightweight. It is crystalline in nature in its unaltered state. When it is prepared for usage, it develops a chalk-like quality. It maintains its original crystalline state when combined with water. To create a smooth surface, this substance can be put over a block, brick, or concrete surface. It is available in a format that is ready to use and doesn’t require sand. All that has to be done is add water.  It provides levelled walls with the highest polish and great thermal and acoustic qualities.

Gypsum plaster provides a smooth interior finish and is an ideal base for good quality paints and wallpaper finishes. It can be applied on both smooth and rough surfaces of the wall. Gypsum plaster is easy to apply and requires less skilled manpower unlike the traditional cement mortar. The preparation of surface and application of gypsum plaster should be apt to prevent cracks and peel offs.

Storage of Gypsum

The surfaces exposed to moisture reduce the setting time and strength of gypsum plaster. So, gypsum bags have to be stored on elevated as well as a dry platform made of timber, brick or concrete. The shelf life of gypsum plaster is usually 3-4 months from the date of manufacture. If stored properly under suitable conditions of temperature and humidity, its shelf life can be increased by another 6 months.

Gypsum Plaster Thickness

It can be used in thicknesses ranging from 6 to 20 mm. Gypsum plaster’s undercoat typically measures 11 millimetres for walls and 8 millimetres for ceilings, while the thickness of the finish coat is 2 millimetres. To prevent cracks, it is advised to apply gypsum plaster at a minimum thickness of 6 mm. If a wall needs more than 20mm of plaster built up, an initial dash coat of cement sand plaster is placed for a thickness of 8–12mm, and the final thickness of not less than 6mm of gypsum plaster is put to provide a smooth finish.

Method of Application

Gypsum plaster is used in the following manner after surface preparation:

• Most Gypsum Plaster is sold in ready-to-mix bags. In a clean, dry container, combine the powder with the water and swirl for two to three minutes.
• Make sure the required plaster is not more than 13 mm thick.
• Firmly press gypsum plaster onto the surface.
• Continue flattening while the plaster stiffens. When the plaster is sufficiently set, wash the surface as needed with a sponge float and water.
• Gradually trowel the surface to achieve a smooth finish.
• Plaster surfaces need to be shielded from ongoing moisture exposure.
• The painting should begin once the surface has dried sufficiently. 

Properties of Gypsum Plaster

• Because of its minimal weight, plastering does not add to the building’s structural burden.
• In contrast to cement plaster, gypsum plaster does not shrink throughout the drying and hardening processes.
• It is less prone to cracking. 
• Gypsum has a high concentration of crystal water and is non-combustible. It serves as a fire barrier and safeguards the steel, concrete, and block construction.
• Gypsum plaster boosts the longevity of metal fittings like pipes by preventing rust.
• Gypsum plaster ensures energy and electricity savings due to its low thermal conductivity.
• Plaster made of gypsum has a high tensile and flexural strength.

Advantages of Gypsum Plaster

Heat Resisting

Gypsum plaster is both highly resistant to fire and harsh temperature conditions.

No cracks on Shrinkage

When conventional cement and water are combined, some heat is generated. When gypsum and water are combined, very little heat is produced, yet this heat can be seen as surface fissures. There are thus no surface cracks. 

Easily accessible in markets

Some marketplaces do not carry certain resources, such as natural sand. However, gypsum is offered in all marketplaces and can be purchased in a ready-to-use state.

High Strength 

Gypsum Plaster is lightweight and extremely durable. This automatically lowers the structure’s overall dead load.

Polished Surface

Walls can be plastered with gypsum without having to worry about ruining the surface. Due to the texture of the material, even the corners of the wall can be perfectly lined.

Simple to Use

Gypsum plaster can be placed directly on concrete surfaces, bricks, blocks, and other building materials.

Quick Setting Time

Gypsum plaster may be applied on walls in as little as 30 minutes, compared to an hour or more for conventional materials. The walls can be painted 72 hours after the plaster has been set since the plaster must totally dry before painting.

Reduced Water Use

Contrary to traditional plaster used for cementing, gypsum plaster does not require water for curing, so the procedure can be completed rapidly without the use of water.

Useful for interior design

Gypsum plaster is important in interior design and other fields because it can be moulded into a variety of forms and sizes.

Easy to maintain

Gypsum plaster does not require as many quality checks to verify its standard, unlike cement plaster, which necessitates constant observation to ensure that the materials are mixed in the proper proportions.

Disadvantages of Gypsum Plaster

Expensive

Gypsum Plaster is costlier than conventional cement mortar plaster that consists of sand and cement. In areas where sand is not permitted for usage, gypsum plaster has to substitute for the lack of sand and this would increase the overall cost for construction.

Retains moisture

Gypsum plaster is not resistant to moisture and hence, cannot be used for outdoor applications. This material cannot be used in areas that are exposed to water and dampness such as the bathroom, kitchen counter, etc.