- ~10m²per 25kg bag at 2mm
- 2mmnormal skim, two coats
- 1.25kgper m² per mm
- +10%for waste
Coverage per 25kg bag
| Plaster | Used for | Usual thickness | Coverage per bag |
|---|---|---|---|
| Multi-Finish | Skim over board or backing coat | 2mm | ~10 m² |
| Board Finish | Skim over plasterboard | 2mm | ~10 m² |
| Bonding | Undercoat on smooth or dense walls | 8mm | ~3.8 m² |
| Hardwall | Undercoat on brick and block | 11mm | ~3.0 m² |
| One Coat | Patching and one-coat walls | 10mm | ~2.9 m² |
Multi-Finish bags by area
At 2mm with 10% waste.
| Area | Example | 25kg bags |
|---|---|---|
| 10 m² | One wall 4 × 2.5m | 2 |
| 20 m² | A ceiling and one wall | 3 |
| 30 m² | Walls of a small bedroom | 4 |
| 46 m² | 4 × 3.5m room, walls and ceiling | 6 |
The sum
Coverage per bag = 25 ÷ (1.25 × thickness in mm) → 25 ÷ 2.5 = 10m² at 2mm
The plaster calculator works out a whole room, the other plasters and the mixing water.
