Plastering Uses, Advantages. How to Plastering Brick. Cement Sand Water Ratio for Plastering many more discussing here.
Plastering work procedure, Cement Mix Masonry surfaces. Plaster is a thin layer of mortar applied over the masonary surface. It is the process of applying one or more coats of mortar to a concrete surface.
Plastering Process, Cement Mix Ratio
Plastering works as part of finishing works. it helps to build structure protection from harmful environmental influences, increase building lifespan, Improvising sound insulation and fire protection are the purposes of its functions. Portland cement plaster is also one of the most abused materials curring used in construction. Applying mortar coats on the surfaces of walls, columns, ceiling, etc. to get a smooth finish is termed as plastering. Successful plastering depends on proper batching and mixing of the individual and combined materials. its process of covering rough walls and uneven surfaces in the construction places and other structures with plastic material. To provide an even, smooth, regular, clean and durable finished quality plastering used.
Requirement of Plaster
Plastering/ Plaster has important considered requirements in the fresh and hardened plaster states. In the fresh state, the plaster must be workable and cohesive. It should adhere to the background and should remain adhered to during all climatic changes and must be cheap and economical and It should be possible to apply it during all weather conditions.
In a Hardened state, Plaster must be strong enough to hold paint and withstand local impact and abrasion. Free of Unsightly cracking and It should effectively check the entry or penetration of moisture from the surfaces. Have acceptable surface accuracy. It should possess good workability.
Current plastering methods take a long time and consume additional human power. So due to this slow process, the labor cost has also been increased.
The concrete surface should be clean, free of loose debris, porous, and chipped, scarified, etched or otherwise roughened to ensure good mechanical bond. as precautions, Clean all the Joints and surfaces of the wall with a wire brush, there should be no oil or grease, etc. Keep all the mortar Joints of wall rough, so as to give a good bonding to hold plaster. the last one Wash the mortar joints and entire wall to be plastered and keep it wet for at least hours before applying cement plaster. Roughness improves adhesion by providing a positive “key” for the plaster to grip onto. Absorption removes the water film between surface and plaster that would tend to weaken adhesion.
Curing Plastering Setting Time:
Curing has been done the proper way. It must take a maximum time setting. Curing for Plastering shall be done minimum 3 days with Potable water in each coat, Rush coat and final coat. With heavy fall we have to maintain at least 7days for sure. Curing shall be started 24 hours after finishing the plaster. The plaster shall be kept wet for 7 days during which period it shall be suitably protected from all damages.
Portland Cement Plaster:
Portland cement plaster is a combination of portland cement-based cementitious material and aggregate, mixed with a suitable amount of water to form a plastic mass. The plaster will adhere to a surface and harden, preserving any form and texture imparted to it while plastic.
plaster containing the admixtures should be evaluated at the project to establish that the results conform to what is expected. Admixtures should not be used indiscriminately. The use of soaps or detergents should not be condoned, since the uncontrolled air entrained with these materials is detrimental to plaster quality.
Plaster mixtures are very sensitive to admixtures. If plaster must be applied to an absorptive substrate or during extremely dry conditions, an admixture that retards cement hydration can increase and prolong the workability of the plaster.
Indian Standard which helps you to learn more about this. you might have a look
IS 383 Specification for coarse and fine aggregates for natural sources for concrete.
IS 1542 Specifications for sand for plaster
IS 2645 Specifications for integral cement waterproofing compound
IS 8112 Specification for 43 grade OPC
IS 269 Specification for 33 grade OPC
IS 1489 Specification for Portland Pozzolana Cement
Procedure for Cement Plastering on Wall Surfaces
Cement plastering is commonly used as ideal coating for the external and internal surface of wall. Cement plaster is usually applied in a single coat or double coat. Double coat plaster is applied where thickness of plaster is required to be more than 15 mm or when it is required to get a very fine finish. The process of applying a double coat cement plaster on wall surface consists of the following 4 steps.
Step-1: Preparation of surface for plastering
8tep-2: Groundwork for plaster
8tep-3: Applying first coat for under coat or rendering coats
8tep-4: Applying second coat for finishing coat or fine coats.
Plastering materials. All plasters must contain at least one cementitious material for work. generally lime, gypsum (admixture) or Portland cement. Sand is used to increase capacity and to reduce shrinkage. Water is necessary to develop the plasticity of the cementitious material and to assist in the chemical reactions involved in the hardening process.
Dry Plaster: Dry plaster is a facing of surfaces with gypsum boards which are prefabricated and have a various characteristics depending on its use. Finishing work with the application of gypsum boards is a facing of walls and ceilings, an assembly of partitions. Dry plaster can be used only for finishing works indoors because plasterboard consists of the cardboard which can not withstand long atmospheric effects. The dry plaster is also less reliable and does not have as good characteristics of maintenance as the wet condition.
Tools for plastering: The following tools are used for plastering, Gauging trowel, floats, floating rule, plumb bob, straight edge, bushes, set square, spirit level, scratcher, plumb rules, etc.
Cracks due to reasons, Hair cracks or wide cracks formed. if the old surface is not properly dressed, bad workmanship, due to expansion and shrinkage in plaster coat during dring might reason to cracks. Due to excessive thermal variations, Inadequate bonding between plaster coats and due to imperfect adhesion of the plaster to the background.