Moreover, small expansion of gypsum is considered significant propertied that prevent shrinkages and cracks. So, important gypsum plaster that is employed as under coat, finish coat, and replaced lime and cement broadly. Gypsum plaster is widely used plaster materials that could be mined naturally or produced as a by-product. Plasticizer is a liquid that added to the mixture to ease plaster spreading over the surface. Mixture of sand and cement might be plastic and require experienced and skill labor therefore plasticizer or lime is added to the mixture usually by volume ratio of 1cement:0.25 lime: 3 sand or 1 cement to 4 sand with plasticizer. Grey powder Portland cement is mixed with water by the ratio of 1cement to 3 or 4 clean washed sand by volume as an under coat for hard background for example brick block walls and partitions. Lime plaster could be used for ancient structure restoration and rehabilitation. Lime plaster might be shrink after drying so animal hair of about 5 Kg is used for 1 m 2 to avoid lime plaster cracking and shrinking. Not only this mixture is used for under coat but also used as finish coat. Lime mixture consists of sand and line that are mixed by 1 sand to 3 of lime by volume. Types of Plaster based on Material Used Lime Plaster Types of Plaster Finishes used in Building Construction are:.Plaster Finishes to Timber Joists and Studs.Types of Plaster based on Material Used.Finally, finish coat is applied for the surface.įigure-1: Advantages of Two Under Coat of Plaster That is why spreading thin layer and permitting to harden followed by employing second under coat is the best practice as shown in Figure 1. This is because thick under coat tend to sag due to weight of thick wet plaster. Moreover, walls constructed from irregular and different size stones might require three coating. In this case under coat which is low cost coarse grain material is used to render the surface followed by finish coat that is thin layer of fine grain materials. However, there are surfaces that irregularities are more than 3cm. Wet materials that spread over wall or roof surfaces should not be more than 0.3 cm. Recently, wall surfaces in modern houses are finished with bricks or blocks or aesthetically pleasing stones to show beautiful appearances. The prime purpose of plastering is to obtain hard and smooth surface that could be painted and provide nice aesthetic appearances. At the beginning, wet materials are spread over the block or brick works and then suitable equipment is used to make the surface smooth level. □ Reading time: 1 minute Plastering is a process by which coarse surfaces of wall or ceiling roofs are changed or turned or rendered to provide smoothness.
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