- 2074 Bhadra · 4 marks
Short note: Mortars used in plastering
Short answer
Plastering mortars include cement mortar (1:3 to 1:6), lime mortar (1:2 to 1:3), cement-lime gauged mortar (1:1:6), mud mortar, and gypsum plaster. Thickness varies: 12 mm internal, 15-20 mm external, 6 mm ceiling. Surface preparation includes cleaning, raking joints, wetting, and curing for at least 7 days.
Write a short note on mortars used in plastering works.
Plastering is the covering of walls, ceilings and other rough surfaces with a layer of mortar to protect them and give a smooth, decorative finish. The mortar must be workable, adhere well and be durable.
Mortars used
| Mortar | Mix | Use |
|---|---|---|
| Cement mortar | 1:3 to 1:6 (cement : sand) | External plaster 1:4; internal 1:6; ceiling 1:3 |
| Lime mortar | 1:2 to 1:3 (lime : sand) | Old/heritage works, internal plaster |
| Cement-lime (gauged) mortar | 1:1:6 | Good adhesion, workable, internal and external |
| Mud mortar | Clay + straw | Rural houses of Nepal |
| Gypsum plaster | Gypsum + water | Internal smooth finish |
Practice
- Thickness: 12 mm for internal brick walls, 15-20 mm for external walls and 6 mm for ceilings; in two-coat work the finishing coat is about 6 mm.
- The surface is cleaned, the joints are raked to give a key, and the surface is wetted; plaster is then applied between level guides (screeds).
- Plaster is cured for at least 7 days.
Sand should be clean, well graded and free from clay and silt.
✓ Answer checked by Claude Opus 5.5 (high effort)
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