Plastering the process of applying thin cover of cement mortar over the exposed surface in order to safeguard against penetration of rain water and other atmospheric agencies. It improves the appearance of the structure and gives decorative effect to the interiors.
For good plaster, it is essential that the plaster should have proper bond with the surface of masonry to be plastered. For this the surface should be prepared by adopting following steps.
- All the projections extending more than 13mm from the general face of the masonry should be knocked off.
- All the joints in the masonry should be raked for a depth of about 20mm for good bonding between the cement mortar and masonry.
- Oily, greasy and any efflorescence spots should be removed by brushing or scrapping.
- On old surfaces, the surface should be made rough before applying the plaster.
- Before applying plaster over the surface, it should be thoroughly washed by water to remove any loose material and keep it wet.
- Water to be used for plaster work should be potable and free from soluble salts. Read our article on Tips for water used for construction
- Uniform thickness of plaster should be maintained to avoid irregular finish.
- Usually on ceiling 12mm thick and on walls 15mm thick plaster should be done.
- The proportion for plaster on ceiling should be richer than 1:3 and for walls it should be richer than 1:6.
- The plaster should be cured by sprinkling water at least thrice a day for minimum 7 days.