Hello Civil Engineers, after reading this article you will learn about the best standard practice we follow at the work site for plastering walls.
Before doing plastering work in walls.
Before doing plastering in brick walls, at least for 7-10 days, you need to cure it properly. At concrete and brick joints use chicken mesh wire, so that plaster will long last on it. Properly do hacking on the concrete surface by hammer and chisel before applying the plaster coat. Brickwork outer surface should be a rough and proper groove in it. The surface which is to be plastered should be free from dust particles, oily materials, and plastic tapes. And then the surface should be wetted properly before 1 hour of plastering.
During plastering walls
The main aim of plastering the wall is to provides even surface which makes it aesthetically goods. Also, it provides protection to the walls.
Make a slurry of cement and sand in a ratio of 1 part of cement and one part of sand (1:1) and spray over the walls properly before 1 or 2 minutes of starting plastering, it helps to make good bound between wall and plaster. Then with the help of trowel put mortar over the wall surface properly.
Note: The ratio of cement and sand kept by measuring and should be mixed well. Mortar should be made up in a small quantity as per requirement only and should be used within one hour.
After plastering the walls
After 3-4 hours of laying plaster, the walls or surface should be covered with wet gunny bags and left undisturbed for 4 days with water curing continued. You need to cure plaster at least 3-4 times per day depending upon the temperature of the surrounding for up to 7 days – 10 days. Due to curing, the hydration process will complete in time which helps plaster to gain its strength.
Tips for plaster mortar (cement:sand ratio)
A) For internal walls, cement, and sand ration is taken up to 1:6 with a maximum of 12mm-15mm plaster thickness.
B) For the ceiling, cement, and sand took in 1:4 ratio with a maximum 8mm – 12 mm plaster thickness.
C) For external walls, the cement, and sand is taken in 1:5 ration and 12mm – 20 mm plaster thickness. In outer or external walls, if you want to provide a single coat of plaster only then it will be of 12mm thick only. It depends upon whether you want to provide a single or double coat of plaster. If you want to provide a double coat, the first coat should be of 12 mm and the second coat of 8 mm thick. The first coat should be cured for at least 3 days before applying the 2nd coat. The surface of the first coat should be scratched or roughen before it is fully hardened.
Due to the Double coat of cement plaster, the brick will not soak the water. If you need to decrease the cost of plastering in the outer surface, use the mortar of 1:6 in the first coat and 1:4 in the second one.
Note: Always you waterproofing during painting at outer walls. And, in the bathroom or kitchen, if you want to puts tile on walls, then make roughness on the plaster surface. Due to roughness or scratches in-wall, tiles make great bounding.
Tips for good plasterwork
- Rough surface preparation by hammer and chisel is very important in plastering, it ensures that the plaster lasts longer.
- The surface should be clean and wet before applying mortar over it.
- If the wall where you are doing plaster is too wet use dry cement masonry.
- Use cement slurry then use mortar with a trowel.
- Before making mortar, always screen the sand (only use screened sand to get a good quality of plaster and finishing).
Defects or Problems seen in Plasters:
Defects on the plaster affect the aesthetic view of the building although it has no relation with the safety.
White patches are seen in plaster due to the presence of salt in building materials. Fine cracks of a hexagonal pattern seen due to having high slit content and also due to the use of pure cement as a finishing coat.
Tips for minimize the defects or avoids the defects on the plasters
- By using well-graded sand in plaster.
- By avoiding a rich mortar mix.
- Avoid over trowelling.
- Avoid too thick layer of plaster.
- Don’t use pure cement for finishing purposes.
- By proper and sufficient curing of plaster.
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