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Describe the procedure for carrying out the Plastering in cement mortar in two coats.
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• The mix ratio of mortar in case of cement plastering depends upon the nature of the work to be plastered.

• For rich plastering work at sensitive places (e.g. in side bathrooms, W.C. etc.), 1:3 cement plaster mix is used. For general plastering of walls 1:5 to 1:8 cement plaster mixes are used.

Preparing the surface

• Before applying the plaster, the surface should be prepared properly.

• The joint of masonry are properly raked to a depth of 20 mm to provide key to plaster.

• The surface is then thoroughly wetted with water, washed well and kept wet for six hours.

• When the surface is ready, plaster is applied.

Applying the plaster

• Cement plastering may be applied in one or two coats.

• In case plastering is to be done in two coats the first coat is applied as described below.

• The mortar is dashed against the prepared surface into a uniform thickness with the help of trowel.

• Wooden screeds 7.5 cm wide and of required thickness of the plasters are generally fixed vertically 2.4 to 3 m apart to act as gauges/ guides in order to keep the plaster to the required thickness. Careful plumb line should be done in fixing of these screeds.

• Surplus mortar is removed with the help of mason’s straight edge and then the mortar is pressed well with a wooden float so that mortar may fill in the joints of the masonry.

• The thickness of this coat should not be more than 16 mm.

• Before applying the second coat, the first coat is allowed to set but it should not become dry and it is also roughened with a scratching tool to provide key to the second coat.

• The second coat is then applied in a thin layer not exceeding 3 mm in thickness within 48 hours.

It is then well trowelled and rubbed perfectly smooth with the help of a steel float. It is then allowed to set for 2 days and cured for more than 7 days.

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