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Johny AJ
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July 11
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5 Minutes Read
Traditional Lime Plastering
Traditional lime plaster is a type of plaster that has been used for centuries in the construction and restoration of historic buildings. It is typically composed of lime, sand, water, and sometimes natural additives based on their nativity. The lime used is typically non-hydraulic hydrated lime. Lime plaster is known for its durability, breathability, and flexibility, which allows it to adapt to the movement and settling of a building over time. The sand used in lime plaster can vary in size and texture, depending on the desired finish. Lime plaster is often applied in multiple coats, with a base coat used to level the wall or surface, and one or more additional coats to achieve a smooth, even finish. Lime plaster is widely used in restoration projects to match the original historic plaster
Properties:
Natural Material: Lime plaster is made from a mixture of lime, sand, and water. It is an eco-friendly and natural alternative to modern cement-based plasters, which are more resource-intensive to produce.Breathability: Lime plaster is highly breathable, allowing moisture to pass through it. This quality helps regulate humidity levels inside buildings and prevents the accumulation of moisture, which can lead to mold and decay.Self-Healing: Lime plaster has the ability to self-heal hairline cracks that may develop over time. The carbonation process, where lime absorbs carbon dioxide from the air, enables it to re-crystallize and fill in small cracks, ensuring the integrity of the plaster.Flexibility: Lime plaster is flexible and can accommodate slight movements in the structure of a building without cracking. This flexibility makes it suitable for older and historic buildings that may experience some degree of settlement or movement.Fire Resistance: Lime plaster is naturally fire-resistant, making it an excellent choice for protecting building interiors. It can help slow down the spread of flames and can even prevent a fire from penetrating the plaster for a significant amount of time.Aesthetic Appeal: Lime plaster has a unique appearance that adds character and charm to buildings. It can be applied in various textures and finishes, including smooth, polished, or textured surfaces, allowing for a range of decorative possibilities.Sustainable and Recyclable: Lime plaster is a sustainable material as it can be easily recycled or reused. If a building undergoes renovations or is demolished, lime plaster can be crushed and used as a base for new plaster or as a soil amendmentHealth Benefits: Lime plaster is a non-toxic material and does not emit harmful volatile organic compounds (VOCs). It also has natural antimicrobial properties, which can help inhibit the growth of mold, fungi, and bacteria on the surface.Longevity: When properly applied and maintained, lime plaster has excellent durability and can last for many decades or even centuries. Historic buildings with lime plaster interiors and exteriors stand as a testament to its long-lasting nature.Applications:
Interior and External Plaster to achieve a smooth, durable finish.Creating decorative finishes, such as stucco, for exterior walls of buildings.Covering masonry or brickwork to protect it from the elements and help regulate humidity within buildings.As a mortar for joining masonry or brickwork in historic buildings.As a base for fresco painting, a traditional painting technique where pigments are applied to the wet plaster surface to create a mural.1. Traditional Lime Preparation.
Materials: LimeStone, Kaduka(Galnut), Karupatti(Jaggery), River Sand, Purified Water.
Equipments: Mixer, Trowel, Gloves, Eye Mask.
Procedure:
Lime Water Extraction: LimeStone is added to a pit of water and allowed to hydrate for 24 hours. Since this is an exothermic reaction, a lot of heat is generated. Hence it is necessary to allow it to cool down before extraction. This process is known as slaking.The Lime water produced is sieved to remove the lime sludge and then added to the mixer grinder along with river sand in the ratio 2:3 for lime water to river sand until a homogeneous consistency is achieved.The prepared mortar is allowed to rest for 7-15 days to the lime particles to further absorb water and ensure a more cohesive and manageable plaster. This is still a weak mortar with low binding capacityThe putty after the resting period is put back into the mixer grinder followed by Kaduka and Karupatti in a fermented state. These natural organic additives slow down and accelerate the setting time and increase the mortar's workability. Lime water is added to adjust for favorable consistency.This mortar is stored on sheets so that the load surfaces should not absorb water in mortar.Rough Ratio: 30 bags of limestone requires 50-100 L of water. To this 25-30 L of both Kaduka and Karupatti are individually added in fermented form.
Precautions:
The entire process is to be free of the presence of salt. Work in a well-ventilated area to minimize exposure to lime dust and fumes.Lime plaster is made by hydrating quicklime, also known as lime putty or slaked lime, with water. It is important to achieve the right consistency and ensure proper hydration of the lime.Allow sufficient curing and drying time for the lime plaster to achieve strength and durability.It is to be ensured that the lime water preparation occurs in a covered situation. Usage of gloves, eye masks and trowels to ensure a safe extraction of lime milk.Lime milk extraction from lime Water Pit
Lime Water
Sieved sand for preparing lime mortar
Kaduka and Karupatti extraction and filtration
Stored Lime mortar taken to mixer again
Final Mixing to prepare an aggregate
Final Lime Plaster produced
2. Traditional Lime Plastering
Equipments: Chisel, putty knife, Hawk, Float.
Procedure:
Step 1: Plaster Chipping: The wall surface is removed of any previous plasters and ensured to be devoid of any loose plaster, dust, or debris. Use a brush, vacuum, or damp cloth to clean the surface. Any cracks were filled with dicofill
Step 2: Plaster Coat 1: Apply a base coat or scratch coat of plaster onto the prepared surface. Use a trowel to spread and level the plaster evenly, ensuring proper adhesion to the substrate. This is then allowed to cure for 7-15 days.
Step 3: Plaster Coat 2: Subsequent coat with a composition of Pure sand and Lime Water. This also allowed to cure for 7 -15 days
Step 4: Lime Milk: The third coat is done here along with the second coat which is the application of lime water followed by curing.
Step 5: Painting: Preferred Paint is applied to finish the surface.
Chipping and removal of old Plaster
After Plastering
Precautions:
To be careful on removing the plaster of decorative motifs, in order to limit the damage done to the existing load bearing brick masonry work.Ensure that the substrate or wall surface is properly prepared before applying lime plaster. It should be clean, free of loose materials, and adequately dampened to promote adhesion and prevent rapid drying.Usage of moulds on executing the intricate decorative motifs and elements such as cornices, architrave, vertical moulding to avoid uneven decoration and to maintain the symmetry.The restoration/replacement of decayed structural wooden members, shall be carried out, after the provision of adequate support/propping to the existing structure.The areas exposed internally or externally for carrying out restoration, strengthening and general civil work, shall be completed in stipulated time period and shall not be kept incomplete for long duration, whatsoever may be the reason or obstacle.References:
Wikipedia Contributors. 2023. “Lime Plaster.” Wikipedia. Wikimedia Foundation. July 7, 2023. https://en.wikipedia.org/wiki/Lime_plaster.http://www.hunnarshala.org/uploads/2/5/9/5/25955121/lime_booklet.pdf 
