Procedure : 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 1:4 to 1:8 cement mortar is used.
Preparing the surface
• Before applying the plaster, the surface of wall shall be cleaned, free from loose particles/dust and wet in advance.
• The joints of masonry are properly raked to a depth of 10 to 15 mm to provide key and bonding between wall and plaster.
• All the cavities and holes in the wall should be properly filled up in advance.
• 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 mortars screed or bands and patches (dots) of plaster of required thickness shall be made on the surface vertically and horizontally at center to center distance of 2 M and evenness of plastered surface shall be checked by plumb bob and plain wooden rule.
• The mortar is dashed against the prepared surface into a uniform thickness with the help of trowel.
• 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 within48 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 8 to 10 days.