Gypsum plastering is an environmental friendly alternative to traditional sand-cement application for internal plastering surfaces.
Gypsum plastering is also a faster application method for internal surfaces, since it does not require time consuming water curing process. Water curing process is mandatory for 20 – 21 days after sand-cement plastering to reduce shrinkage cracks arising due to heat of hydration.
Gypsum plaster is mixed with clean water in recommended proportion at site to make a consistent slurry. Gypsum plaster slurry is then applied at desired thickness on walls and ceilings by trained applicators, this process is called as Gypsum plastering.
Used for centuries in the construction space
Gypsum plaster had been used for centuries in the construction space and is time tested process for plastering interior walls. Gypsum plaster provides excellent thermal and acoustic properties while providing superior rich and smooth finish. Gypsum plastering is now very popular in India and today is preferred choice of builders in most metro markets like Mumbai, Pune, Bengaluru, Delhi NCR, Hyderabad and Chennai.
Gypsum Plasters – FAQ’s
Gypsum is chemically termed as Calcium Sulphate dihydrate (CaSO4.2H2O). There are three broad kinds of gypsum which are found across the world.
Naturally gypsum is found below the earth’s surface like other minerals and this gypsum is called Natural Gypsum. The Natural gypsum is mined and extracted below the earth’s surface using conventional means. In India, natural gypsum is found largely in Rajasthan.
Gypsum is also formed as a by-product of the salt manufacturing process and this gypsum is called Marine gypsum. In India marine gypsum is found in Tuticorin and Gujarat where the salt pans exist.
Thirdly gypsum is also formed as a by-product of industrial manufacturing processes like fertilizers, copper and power. The gypsum thus formed is called synthetic gypsum and is also referred to as phosphor gypsum & DSG depending on the type of manufacturing process.
Gypsum Plasters in India is governed and adopted by Indian Standards Institution (IS:2547), drafted by Gypsum Building Materials sectional committee and finalized by the Civil Engineering Division Council.
Gypsum Plasters are tested on the basis of their physical and chemical properties. These tests are revised into two parts: Part I deals with all Gypsum Plasters with or without “light weight aggregates”.
This method covers the tests determining Normal consistency (%), setting time (minutes), compressive strength (N/mm2), transverse strength (N/mm2), soundness, expansion (%), freedom from coarse particles (residue on 150micron mesh) & bulk density (kg/M3).
Part II deals with Gypsum Plaster containing premixed “lightweight aggregates” and necessarily complying to IS: 2547 (Part 1).
This method of testing determines:
Above tests are conducted at regular intervals for all Saint Gobain Gyproc Plasters by authorised third party agencies.
Traditionally sand-cement plaster was extensively used for levelling interior walls on Bricks, AAC Blocks, Concrete Blocks & RCC surfaces. In certain markets to achieve crack free and smooth finished walls, 3mm to 6mm of gypsum plaster is applied over sand-cement plastered surface, this is called as gypsum punning.
No Shrinkage Cracks
Saint-Gobain Gyproc gypsum plaster is completely free from shrinkage cracks due to is self-setting properties.
Shrinkage cracks occurs in sand-cement plaster due to sudden change in moisture of concrete arising out of heat of hydration. To control heat in concrete and reduce shrinkage cracks in sand-cement plaster, water curing process is mandatory for 20-21 days. Water curing is labor intrinsic and time consuming. Monitoring of water curing process for large projects is a big challenge.
Saint-Gobain Gyproc gypsum plaster does not require any water curing. Gypsum Plaster with adequate initial and final setting time improves workability and provides a ready paintable surface within 3-4 days. This is net savings of 24 days of construction time.
Sand-cement plaster is mixed at site in various proportions (4:1 or 5:1) to arrive at desired strength. Sand-cement plaster requires total 28 days (water curing + POP punning) complete curing of surface to attain paintable surface.
Light weight Construction
Saint-Gobain Gyproc gypsum plaster is 50% lighter in weight (density of approximately 700Kg/m3) in comparison to traditional sand-cement plaster (density of 1860 kg/m3). Using Saint-Gobain Gyproc gypsum plaster for internal plastering thereby decreases the load on the building. Technologically Saint-Gobain Gyproc Gypsum Plaster is light weight but still conforms to standards of the compressive strength required for Internal plastering.
Saint-Gobain Gyproc Gypsum plaster comprehensive strength ranges from 8N/mm2 to 4N/mm2**
**Above parameters are tested under lab conditions.
No Curing (Water Saving)
Saint-Gobain Gyproc gypsum plaster gives freedom from water curing process thus saving cost of water and labour.
Sand-cement plaster requires water for curing to the tune of 0.6 kg/m2/day. A project of 1 Lac sq-m will require water to the tune of 60000 liters daily. With minimum curing time of sand cement plaster as 25-28 days, the quantity multiplies manifold.
Water required for sand-cement per square feet is 1.56 Litres
Water required for Gypsum plaster per square feet is 0.00092 Litres
Elimination of River Sand
Saint-Gobain Gyproc gypsum plaster comes in ready to use bags. Just addition of Saint-Gobain Gyproc gypsum plaster to clean water at site in prescribed proportion and we are ready for plastering. Gypsum plaster is a most proven alternative method to Sand-cement plaster for internal plastering applications. River sand mining is strictly banned in many states of India.
GREEN Building Certified
Saint-Gobain Gyproc gypsum plasters are infinitely recyclable.
Saint-Gobain Gyproc gypsum plasters are GRIHA and GreenPro certified. “GRIHA and GreenPro” certifies that the Saint-Gobain Gyproc gypsum plasters are environment friendly throughout its Life cycle.
Griha council is joint initiative of “Ministry of New and Renewable Energy”, “Government of India” and “The Energy and Resources Institute (TERI)”. GreenPro is an initiative by Indian Green Building council (IGBC).
Saint-Gobain Gyproc gypsum plasters also conforms to LEED requirements which helps in getting “US Green Building Certification” (USGBC).
Reduced Electricity Bills
Saint-Gobain Gyproc gypsum plasters have low thermal conductivity (0.25 W/m-K) as compared to Sand Cement Plaster (0.72 W/m-K). Lower the thermal conductivity of material, higher the insulating properties. Lower thermal conductivity helps in keeping house cool in summer and warm during winter which in turn save energy cost.
The exact difference in temperature can be calculated basis various parameters and quite complex theoretical calculation.
Sand-cement Plaster has two major variables, cost of both vary every month depending on the market demands. River sand mining is banned in many cities of India resulting in sharp increase of cost and inconsistent supplies. Depending on location, cost of Sand-cement plastering for 16-18mm thickness ranges between Rs. 23-27 per Square feet (labour + material).
Loss of sand during transit from distributor to site is approximately 5%-7%.
Moving sand in open barrow from storage heaps to plastering area, incurring loss of 5%-10%.
Sand is then manually sieved to remove large sized pebbles, there by incurring loss of 5%.
Mixing process of Sand & cement generally takes place on floor, adding to another 5% to 7% wastages.
Due to these inefficiencies in sand-cement plastering cost further goes up by another 20-30%.
Saint-Gobain Gyproc plasters are packed in high quality attractive 20Kgs & 25Kgs bags, these are easily transported and can be safely handled at site.
Saint-Gobain Gyproc plasters are manufactured in our World class manufacturing units in Mumbai, Bangalore, Rajasthan. Saint-Gobain Gyproc plasters are mixed with water in buckets with no loss or minimal loss of material. Gypsum plaster slurry is then applied directly over properly prepared surfaces on Bricks, Blocks, RCC etc. Saint-Gobain Gyproc plaster can be applied from 6mm thickness to 18mm thickness in one coat, with no shrinkage cracks. Saint-Gobain Gyproc plasters is cost effective due to higher productivity and reduction in construction time by 24 days.
Gypsum plastering at 13mm thickness will cost in range of Rs.22-30/- per square feet,
** prices vary depending on distance of project from factory, scale of work, skilled labour’s availability in towns.
Gypsum plaster by design has definite savings
Gypsum, a hydrated calcium sulphate (CaSO4. 2H2O) is white or pale yellow coloured depending on the sources. Saint-Gobain Gyproc gypsum plasters are manufactured with high purity gypsum and processed at fully automated machineries thus giving consistent quality. Saint-Gobain Gyproc gypsum plasters is further blended with special additives and retarders to make it suitable for Gypsum plastering. Special retarders added in Saint-Gobain Gyproc plasters increases working time for plastering (setting time from 15 – 25 Minutes) thereby reducing wastages in bucket and spillage during application (maximum wastage 5%). Saint-Gobain Gyproc gypsum plasters with special additives makes it light weight and increases productivity by 20%
Plaster of Paris (POP) found in most parts of India are manufactured with low purity and manually operated machines producing inconsistent quality. Plaster of Paris (POP) with low purity and inconsistent quality have lower setting time ranging between 3 min to 6 min, resulting in higher wastage in buckets (Minimum 10% - 20%). Due to inconsistent quality of Plaster of Paris (POP) it develops shrinkage cracks and hence is not suitable for plastering.
Saint-Gobain Gyproc is specialized in execution of Large and mega projects for internal plastering in major cities of India. Saint-Gobain Gyproc offers a host of services that are needed for large and mega projects that help make appropriate choices for their plastering needs. Currently Saint-Gobain Gyproc have supported in successful completion of projects like residential buildings, hospitals, hotels and government organizations.
Mockups are conducted by Saint-Gobain Gyproc plasters at large projects. This activity helps to get coverage per square feet of Saint-Gobain Gyproc plasters in actual site conditions. Coverage derived at site will support the project team to calculate “cost of material” per square feet.
Saint-Gobain Gyproc can recommend gypsum plastering contractors capable of executing large projects. These gypsum plastering contractors are regular users of Saint-Gobain Gyproc plasters and have a team of trained applicators to deliver “superior quality”, “higher productivity”, “less wastages” at site and “follow safety guidelines”.
Saint-Gobain Gyproc have technically equipped and trained technologists. Saint-Gobain Gyproc technologists regularly conduct inspection during their site visits. During site Inspection, technologist observe application methods followed at site and suggest improvements wherever required. “Plastershala” is training provided to site applicators by our trained personnel. Plastershala are conducted with prior approval from project managers at regular intervals to improve labour productivity.
In some metros, Saint-Gobain Gyproc plasters reach** directly to projects from manufacturing plants or warehouses. You can be rest assured about genuine Saint-Gobain Gyproc plasters reaching your project. There is no need of spending time in arranging vehicles for picking material from distributor.
**Depending on location, minimum order quantity is required for site delivery.
In large projects, it is observed to have uneven walls. Best time to get it rectified is during erecting the wall itself but there are ways to get it rectified during gypsum plastering also.
Saint-Gobain Gyproc plasters are applied directly over various surfaces and is executed in four stages:
Step1 - Setting out to achieve right angled corners between walls and floors with 3-4-5 method. Dabs are placed at fixed distance and thickness as required after proper calculations.
Step 2 - Making level strips with Saint-Gobain Gyproc plaster joining 2 Dabs from top to bottom.
Step 3 - Filling Saint-Gobain gypsum plaster between two level strips using appropriate plastering tools
Step 4 – Final finishing to remove small unfilled portions and give smooth finish.
Saint-Gobain Gyproc plasters offer added benefits viz. higher coverage and less wastages
Saint-Gobain Gyproc plasters have lower density as compared to basic stucco plaster available in the market. The average density of our Saint-Gobain Gyproc plasters is approximately 700 kg/m3 which are significantly lower than basic stucco (1000 kg/m3) thus providing 30% higher coverage.
Saint-Gobain Gyproc plaster are manufactured at fully automated factories to deliver consistent quality and higher setting time of 15-25 minutes. Thus giving freedom to use entire bag of Saint-Gobain Gyproc plasters without wastages.