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Builders and contractors prefer gypsum plaster due to its superior finish and time saving attributes, writes Venkat Subramanian.
In recent years, the construction sector has witnessed a number of new trends, technology advancements and innovations across applications, all aimed at making construction faster and delivering higher performance.
However, very few would have imagined that the substitute for the generations old method of sand cement surface plastering will be an even older method of plastering i.e. gypsum plastering. Gypsum has proved to be a miraculous material aiding interior construction. Gypsum surface plaster is one form that has caught the attention on the sector and is growing in popularity.
The oldest example of usage of gypsum as an internal plaster is found in the Pyramids of Giza in Egypt which were lined with gypsum stucco plaster centuries ago and are still intact, which is proof of the durability & performance of this product.
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Gypsum is a light weight material which is formed as the result of evaporating sea water in massive prehistoric basins. In terms of its chemical composition, it is Calcium Sulphate Di-hydrate (CaSO4.2H2O) and inherently contains 21% water by molecular weight.
Gypsum products have been used for centuries in the construction space and are the material of choice because of gypsum’s unique properties. It has excellent insulation properties both thermal and acoustic and can offer very good passive fire protection, moisture resistance, impact resistance and vapour control when used in combination with the right systems.
What is Gypsum Plaster?
When a wall is constructed with brick or block, they are finished with a coat of plaster which is called internal plastering. Internal plastering has traditionally been done through a process of sand-cement plastering finished with POP pruning.
This is a two stage process and involves multiple elements like sand, cement and water which is mixed onsite. This form of plastering is being slowly replaced by a direct single coat application of gypsum plaster.
So gypsum plaster is actually a replacement of two processes i.e. sand cement plastering & POP punning. Gypsum plaster is produced as a result of calcinations of the raw gypsum in an automatic kettle under controlled temperature.
Advantages of Gypsum Plasters
Sand Cement Vs Gypsum Plaster ~ Ingredients
Sand Cement Plaster Gypsum Plaster
• Cement Gyproc One Coat Elite – 25 Kg Bag
• Sand Water
• Water
• POP/Putty
Sand Cement Vs Gypsum ~ Material Preparation
Sand Cement Plaster Gypsum Plaster
• Screen Sand Quality checked, 25 kg bags ready to use
• Wash Sand Mixing in cans – ensures zero wastage
• Site mixing
• No quality control
Sand Cement Vs Gypsum ~ Application
Sand Cement Plaster Gypsum Plaster
• Sand Cement Plaster is applied within Level Patches (Level Dabs) which does not ensure line & level surfaces.
• Gypsum Plaster is applied within level strips which ensure line & level surfaces.
Sand Cement Vs Gypsum ~ Post Application
Sand Cement Plaster Gypsum Plaster
• Water curing for 7 days minimum No Water Curing
• Coat of leveling material required before painting (POP) Dries in 3 days
• Attains full strength after 28 days Start painting directly
Sand Cement Vs Gypsum Plaster ~ Smooth Crack Free Surface
Sand Cement Plaster Gypsum Plaster
• Shrinkage Cracks No shrinkage cracks
• Increases thickness up to 50mm Thickness of wall lining limited to 15-20 mm
• Cannot achieve Line, Level & Right angle corners Perfect line and level achievable
Sand Cement Vs Gypsum Plaster ~ Finishing
Sand Cement Plaster
• Need to use POP to finish
• With POP – cracking of surfaces occurs
• POP - Increases the thickness of wall (20-30mm) & reduces the carpet area substantially
• POP – Wastage is as high as 30-40%
Gypsum Plaster
• Direct application on brick, block or RCC, no separate finishing product required
• Perfect Line and level with sharp corners and edges
• Smooth finish
• Ready to paint
Benefits to builders / developers:
1. Green material
2. Shrinkage crack free surfaces - smooth finish
3. High productivity – faster work (Reducing plastering time by 70% when compared to conventional Sand cement plaster + POP method) so time saving
4. Performance – Durability, light weight (Reduces dead load on structure)
5. Cleaner sites - direct application bagged product – requires no water curing
Benefits to the end customer:
1. No shrinkage cracks on walls and ceilings
2. Reduction in the time required for plastering and this helps in timely possession of homes
3. Perfectly lined, leveled, smooth walls
4. Saving on electricity used for air conditioning as gypsum has very low thermal conductivity
In the last few years, gypsum plaster has become the solution of choice for all leading builders especially in Mumbai and Pune and is now starting to catch on with developers in other cities like Bengaluru, Hyderabad, Chennai and Delhi.
Many builders such as Lodha, Hiranandani, K Raheja, Magarpatta, Oberoi, Rohan, HCC, Rustomjee to name a few have adopted this method of plastering for a majority of their projects for its sheer convenience over traditional plastering and aesthetic appeal.
ABOUT THE WRITER: Venkat Subramanian is the managing director of Saint-Gobain Gyproc India, which markets a range of CII–IGBC approved gypsum plasters under the brand name - Gyproc Plasters - manufactured at its modern plant at Wada, near Mumbai.
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COMMENT
I want to know 1)what is costing gap in sand plaster & gypsum? 2)what is its effect on painting cost? 3)Can Gypsum Plas