Characteristics of gypsum finish.
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate (CaSO4: 2H20). It is widely used as fertilized, in mold, in carvings and as plaster material.
Gypsum is a chalky material and it is very light. It is available in crystalline form in nature.
In recent years, the construction sector has seen a number of new trends, technological advances and innovations in all applications, all of which are aimed at accelerating construction and increasing efficiency . Gypsum, although a much older material than cement-sand plaster, has rarely been widely used in construction. Currently, Gypsum has turned out to be a wonderful material supporting interior design due to its properties.
Gypsum modeling and gypsum plaster.
Gypsum plaster is obtained by pulverizing gypsum (calcium sulfate hemihydrate CaSO4 0.5H2O) which is heated to a temperature of 150 degrees Celsius.
After adding water, plaster of paris turns into ordinary plaster (dihydrate) again, causing the resulting material to harden. This curing material can be used to create casting molds and structures.
When dry POP powder is mixed with water, it hardens. This material, which can be applied to the surface of a brick, block or concrete to obtain a smooth surface, is called gypsum plaster.
Previously, a 6mm thick layer of gypsum plaster is usually applied to the top of the cement plaster to give a smooth finish prior to painting. This is a two-step process and involves various components such as sand, cement and water that must be mixed on site. This process is slowly being replaced by the direct application of a single layer of gypsum plaster. In gypsum plaster, the finished POP powder is mixed with water and applied directly to the wall.
Gypsum plaster can be applied directly to any bricks, blocks or blocks, blocks and gypsum boards. Gypsum plaster has good insulating, fireproof and impact-resistant properties. In addition, gypsum and gypsum plaster save a lot of time during construction and have an excellent finish. These properties have clearly drawn the attention of property builders and contractors to the choice of gypsum plaster over traditional cement plaster.
Color of the finished surface: white
Setting time: 25-30 minutes
Coverage area (considering the 12mm thickness): 21 square feet per 25kg bag
Compressive strength: 60-70 kg / cm2
Shelf life: 4 months
Contractors and builders began to give preference to gypsum plaster over the excellent finishing properties and time-saving materials. Some of the advantages of gypsum plaster are:
Ease of application (feasibility): The plaster can be applied directly to the brick / block without a separate finish. It is also very easy to apply and smooth gypsum plaster.
No shrinkage cracks: The gypsum reaction produces less heat compared to the cement-water reaction. Therefore, there are fewer shrinkage cracks in gypsum plaster compared to traditional cement plaster.
Fast setting time: The gypsum sets quickly (ie within 25-30 minutes). Thus, painting can be started 72 hours after the plaster has been applied. The plaster must be dried before painting.
Does not require hardening time: Unlike traditional cement plaster, gypsum plaster does not require hardening, saving water and time during construction.
High Efficiency: Significantly reduces the time compared to traditional cement plaster.
High performance: excellent high strength after drying, durable and light (reduces the structure’s own load)
Smooth finish: perfectly tiled, level, smooth walls and perfectly straight corners
Limited supervision: the quality of the cement plaster should be carefully checked as cement and sand must be dosed properly. In contrast, gypsum plaster does not require the same quality control during application, which reduces the surveillance efforts.
Easily available raw materials: Gypsum is a ready-made available material. Natural sand, which is the raw material used in traditional cement plaster, is difficult to obtain. It is also banned in many states in India.
Fireproof: gypsum plaster is highly resistant to fire.
Low thermal conductivity: gypsum has a low thermal conductivity. This saves electrical costs for heating and cooling rooms in the building.
Decorative application: can also be easily applied for decorative purposes and can be formed into various shapes.
Gypsum plaster can not be used for exterior walls as they retain moisture. It is also impossible to make gypsum plaster in permanently wet places, such as bathrooms, etc.,
Gypsum plaster is more expensive than traditional cement plaster (cement and sand) for the same plaster thickness. However, in areas where natural / river sand is not available for construction, plastering with cement mortar would require a 6mm gypsum layer to finish it, making the cement plaster more expensive.