Rate Analysis — Plaster (External 1:6)

Rate Analysis is the cost-build-up sheet for every BOQ item — it shows how the rate per unit (per m², per m³, per tonne) was derived from constituent inputs: cement, sand, water, labour, contractor overheads, profit, taxes. For external plaster (1:6 cement-sand), the rate analysis builds from materials + labour rates current to the project location + time.

For tender preparation (BOQ pricing), claim defense (contractor justifying actual cost), and contract management (variation order rates), Rate Analysis sheets are mandatory. CPWD General Specifications + state PWD specifications all require rate analyses for every BOQ item; auditors will reject vague lump-sum rates without back-up calculation.

This sheet covers external plaster in cement-sand mortar 1:6 — typical specification for medium-quality exterior wall finish. Rich mortar (1:4) is used for premium / smooth-finish applications; lean mortar (1:8) for cost-sensitive / non-visible applications.

Per 10 m² of 1:6 plaster, 15-20 mm thick (typical external):

Materials: - Cement: ~58 kg (rich 1:6 = 1 part cement : 6 parts sand; ~1.2 m³ dry volume; cement content ~245 kg/m³ × 0.24 m³ = 58 kg) — at ₹400-450/bag = ₹1,160-1,300 - Sand: ~0.21 m³ — at ₹1,500-2,500/m³ = ₹315-525 - Water: ~25-30 L — negligible cost (~₹10) - Materials sub-total: ₹1,500-1,850

Labour (Indian Living Standards estimate): - Mason: 0.5-0.7 day @ ₹600-900/day = ₹300-630 - Helper: 0.5-0.7 day @ ₹400-600/day = ₹200-420 - Labour sub-total: ₹500-1,050

Other: - Scaffolding allowance: ₹100-200 (mostly for above-ground level) - Curing water + labour: ₹50-100 - Wastage on materials (5%): ₹75-92 - Contractor's overhead (10-15%): ₹250-400 - Contractor's profit (10-15%): ₹250-400

Total: ₹2,725-4,092 per 10 m² → ₹273-409 per m²

Actual rate varies significantly with location (metros higher), accessibility (high-rise > ground floor), and labour-market conditions.

1. Wrong cement consumption — for 1:6 mortar, cement is ~58 kg/m² of 15 mm plaster. Some sites compute as if it's 1:4 (~85 kg/m²) — over-estimates cost. Or under-estimate by assuming dry-mix ratio = wet-mix ratio (bulking effect adds ~25%).

2. Sand price not local — using city-A rate for project in city-B. Sand price varies 200-300% between regions (river-sand restrictions / M-sand availability).

3. Labour productivity mis-assumed — 1 mason/day on plaster ≈ 12-15 m² for skilled crew; new hires 7-10 m². Wrong assumption skews labour cost.

4. No scaffolding — external plaster above ground floor needs scaffolding; cost depends on height + duration. Often missed.

5. No curing labour — 7-day curing on external walls needs daily water spray + labour; small but adds up.

6. Wastage too low — 5% is common but practical wastage on remote sites can be 10-15%. Be realistic.

7. Overhead + profit double-counted — some contractors add overhead twice (once in unit rate, once at BOQ level). Mandate single declaration.

8. No GST — taxes on materials add 5-18% depending on item. Must be in rate analysis.

Companion formats: - Rate Analysis Plaster Internal 1:4 (FMT-EST-004) — internal plaster, richer mix - Rate Analysis Brickwork (FMT-EST-003) — masonry construction - Rate Analysis Shuttering (FMT-EST-006) — formwork costs - Labour Productivity Sheet (FMT-EST-007) — per-trade productivity assumptions

Codes / specifications: - CPWD Specifications 2019 — Volume 1 Section 13 (Plastering) - IS 1542:1992 — Sand for plaster - IS 2250:1981 — Code of Practice for Preparation and Use of Masonry Mortars - IS 269:2015 — OPC 33 cement (binder) - IS 1200 Part 12:1976 — Method of measurement (plastering) - State PWD specifications — region-specific rate analysis templates