Plastering
- Ensure that the sand is free from adherent coatings, clay, silt, dust and organic impurities.
- Use coarse sand for the first coat (rendering coat) and fine sand for the finishing coat.
- Rake the masonry joints to a minimum depth of 12 millimetres.
- Brush out dust and loose mortar from the raked joints as well as the masonry surfaces.
- Roughen the smooth surfaces that are to be plastered by wire brushing/hacking to ensure perfect bond.
- Clean away oily/greasy matter, plastic tapes and any other substances sticking to concrete surfaces and wash thoroughly using wire brush.
- Dampen the wall evenly before applying plaster.
- Mix small quantities of mortar such that it can be consumed within 60 minutes after the water is added.
- Ensure that the thickness of plaster does not exceed 15 millimetres in a single coat and 20 millimetres in two coats.
- Roughen the first coat (rendering coat) and keep it damp for a minimum of 2 days or until the next coat is applied.
- Apply the finishing coat over the rendering coat in 2 to 5 days.
- Cure the plastered surfaces for at least 10 days.
- Avoid plastering in extreme temperatures (>40°C).
- Use well-graded sand and the most suitable proportions of cement and sand (1:3 to 1:6).
- Provide two coats of plaster on solid backgrounds.
- Avoid excessive troweling while finishing the plaster.
- Avoid overworking of cement finishes to avoid shrinkage at the top layer.
- Lightly sprinkle water after 30 minutes of finishing the plaster surface.
- Cure the plaster surfaces properly and adequately (minimum of 10 days).