Material quantities (cement bags, sand) required per square metre of plaster work, including standard wastage. Use for material indenting and rate analysis. Quantities depend on plaster thickness, mix ratio, and surface finish — figures below include 15% wastage typical of Indian site practice.
Internal Plaster (12 mm thickness)
Includes 15% wastage. Dry volume = 1.30 × wet volume
| Mix | Thickness | Cement / m² | Sand / m² | Use | Note |
|---|
| 1:3 (rich) | 12 mm | 0.156 bag (7.8 kg) | 0.0156 m³ | Bath, kitchen wet zones | Higher cement, denser finish |
| 1:4 | 12 mm | 0.124 bag (6.2 kg) | 0.0156 m³ | Internal walls (general) | — |
| 1:5 | 12 mm | 0.104 bag (5.2 kg) | 0.0156 m³ | Internal walls (less load) | — |
| 1:6 (most common) | 12 mm | 0.087 bag (4.36 kg) | 0.0156 m³ | General internal — most common | Standard CPWD specification |
External Plaster (15 mm thickness — single coat)
| Mix | Thickness | Cement / m² | Sand / m² | Use | Note |
|---|
| 1:4 | 15 mm | 0.155 bag (7.74 kg) | 0.0195 m³ | Exposed external walls | Sand-faced finish typical |
| 1:5 | 15 mm | 0.130 bag (6.5 kg) | 0.0195 m³ | External, moderate exposure | — |
| 1:6 | 15 mm | 0.108 bag (5.42 kg) | 0.0195 m³ | External, sheltered | — |
Two-Coat Plaster (20 mm = 12+8 mm)
Rough coat 12 mm + finish coat 8 mm — for severe exposure
| Mix | Thickness | Cement / m² | Sand / m² | Use | Note |
|---|
| 1:4 (rough) + 1:3 (finish) | 20 mm | 0.21 bag (10.5 kg) | 0.026 m³ | Sea coast, heavy rain | Best durability |
| 1:5 + 1:4 | 20 mm | 0.18 bag (9.0 kg) | 0.026 m³ | External standard | — |
| 1:6 + 1:4 | 20 mm | 0.16 bag (8.0 kg) | 0.026 m³ | External economy | — |
Ceiling Plaster (6 mm thickness)
Soffit of RCC slab — thinner coat, higher consumption per m³ due to overhead waste
| Mix | Thickness | Cement / m² | Sand / m² | Use | Note |
|---|
| 1:3 (rich) | 6 mm | 0.094 bag (4.7 kg) | 0.0094 m³ | Bath, kitchen ceilings | 20% wastage assumed |
| 1:4 | 6 mm | 0.075 bag (3.75 kg) | 0.0094 m³ | Internal ceilings | — |
| 1:5 | 6 mm | 0.063 bag (3.15 kg) | 0.0094 m³ | Less load ceilings | — |
| 1:6 | 6 mm | 0.052 bag (2.6 kg) | 0.0094 m³ | Standard internal ceiling | Most common specification |
Quick Estimation Formulas
| Mix | Thickness | Cement / m² | Sand / m² | Use | Note |
|---|
| Wet volume of plaster | — | Area × thickness | — | Step 1 | m² × mm/1000 = m³ |
| Dry volume | — | Wet volume × 1.30 | — | Step 2 | 30% extra for shrinkage |
| + Wastage | — | Dry volume × 1.15 | — | Step 3 | 15% wastage on site |
| Cement (kg) | — | (1/(1+R)) × Total dry vol × 1440 | — | Step 4 | R = sand:cement ratio |
| Cement (bags) | — | Cement kg / 50 | — | Step 5 | — |
| Sand | — | — | (R/(1+R)) × Total dry volume | Step 6 | m³ of sand |
Typical Wall Plaster Areas (per room)
| Mix | Thickness | Cement / m² | Sand / m² | Use | Note |
|---|
| 10×10 ft room (4 walls) | — | — | — | Internal plaster ≈ 36 m² | Less openings ≈ 30 m² |
| 12×15 ft hall | — | — | — | ≈ 50 m² internal | — |
| Ceiling (per 10 m²) | — | — | — | ≈ 10 m² ceiling plaster | Same as floor area |
| Whole 1000 sq ft house | — | — | — | ≈ 350–400 m² total plaster | Internal + external + ceiling |
Notes
• These figures include 30% bulking factor for dry → wet and 15% site wastage
• If sand has high silt content, increase cement by 5–10% to compensate
• Always order 5% extra material at procurement to avoid mid-job stoppages
• For sand-faced finish, add 1 mm extra finish coat — consume 10% more material
• Add 5–8 kg cement per m² extra for waterproofing additives where needed
• Use 2.36 mm sieve for plaster sand — fine, well-graded sand gives smoother finish
• Always cure plaster for ≥ 7 days — water spray 3 times daily
• For machine-applied (spray) plaster, output is 3–4× manual but material wastage is also higher
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