--- title: "Rate analysis: 12.5 mm plaster 1:3, per 100 m²" subject: "Estimating and Costing" chapter: 4 key: "semester_7/estimating_and_costing:rate-plaster-12-5-1-3-ceiling" source: https://www.bctengineer.com/q/semester_7/estimating_and_costing/rate-plaster-12-5-1-3-ceiling site: BCT Engineering --- # Rate analysis: 12.5 mm plaster 1:3, per 100 m² Estimating and Costing · Chapter 4: Analysis of Rates - Asked in: 2080 Baisakh, 6+1+1 marks - Video: [Rate Analysis of Plaster Work | Analysis of Rate for Plaster Work @CivilConstruction](https://www.youtube.com/watch?v=n8qR8FVY8Sw) — CivilConstruction - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_7/estimating_and_costing/rate-plaster-12-5-1-3-ceiling - Whole chapter: https://www.bctengineer.com/md/semester_7/estimating_and_costing/chapter-4 ## Question Prepare the analysis of rate for 12.5 mm plastering work in 1:3 cement sand mortar per 100 square meters all complete and as per the instruction of engineer. What modification is required in the given calculation if the plaster work is for ceiling work? Also, justify why lead and lift is important for the analysis of rate work. ## Short answer Rate of 12.5 mm plaster (1:3) wall: NPR 50,123.13 per 100 m² (NPR 501.23 per m²). For ceiling, increase labour 25% and add staging, rate becomes NPR 59,185.63 per 100 m². Lead and lift affect material cost through transport distance and vertical lift, ensuring accurate rate analysis. ## Answer Rate analysis is the work of finding the cost of one unit of an item from the quantities of materials, labour and plant needed and their current rates. The rates and labour norms below are illustrative (DUDBC-style norms; use the current District Rate and norms of the project area for a real estimate): cement NPR 1,000/bag, sand NPR 3,500/m³, 20 mm aggregate NPR 4,500/m³, skilled labour NPR 1,500/day, unskilled labour NPR 1,100/day, water lump sum, contractor's overhead 15% and profit 10% on direct cost (VAT excluded). #### Rate analysis: 12.5 mm plaster 1:3, wall, per 100 m² - Wet mortar $= 100 \times 0.0125 = 1.2500$ m³; dry mortar $= 1.27 \times 1.2500 = 1.5875$ m³ - Cement $= 1/4 \times 1.5875 = 0.3969$ m³ $= 11.43$ bags; sand $= 3/4 \times 1.5875 = 1.1906$ m³ - Labour (illustrative norm): mason 8 days, helper 10 days per 100 m², including mixing, curing and cleaning. | Item | Qty | Unit | Rate (NPR) | Amount (NPR) | |---|---:|---|---:|---:| | Cement | 11.43 | bag | 1,000.00 | 11,430.00 | | Sand | 1.191 | m³ | 3,500.00 | 4,168.50 | | Skilled labour (mason) | 8.0 | day | 1,500.00 | 12,000.00 | | Unskilled labour | 10.0 | day | 1,100.00 | 11,000.00 | | Scaffolding, water and curing (lump) | 1 | LS | 1,500.00 | 1,500.00 | | **Direct cost** | | | | **40,098.50** | | Contractor's overhead @ 15% | | | | 6,014.78 | | Contractor's profit @ 10% | | | | 4,009.85 | | **Total (rate per 100 m²)** | | | | **50,123.13** | **Rate of 12.5 mm plaster (1:3), wall = NPR 50,123.13 per 100 m² (NPR 501.23 per m²).** #### Modification for ceiling plaster The material quantity stays the same for the same thickness (in practice ceiling plaster is often only 6–10 mm thick, which reduces the mortar proportionally). The changes are: - Labour is increased by about 20–25%, because the mason works overhead and the output falls. Wastage from dropping mortar is also higher. - A scaffold or staging cost is added (plus the cost of lifting material to the floor level, if any). Modified rate (labour +25%, staging NPR 3,000): | Item | Qty | Unit | Rate (NPR) | Amount (NPR) | |---|---:|---|---:|---:| | Cement | 11.43 | bag | 1,000.00 | 11,430.00 | | Sand | 1.191 | m³ | 3,500.00 | 4,168.50 | | Skilled labour (mason) +25% | 10.0 | day | 1,500.00 | 15,000.00 | | Unskilled labour +25% | 12.5 | day | 1,100.00 | 13,750.00 | | Staging / scaffolding and water (lump) | 1 | LS | 3,000.00 | 3,000.00 | | **Direct cost** | | | | **47,348.50** | | Contractor's overhead @ 15% | | | | 7,102.28 | | Contractor's profit @ 10% | | | | 4,734.85 | | **Total (rate per 100 m²)** | | | | **59,185.63** | **Rate of ceiling plaster = NPR 59,185.63 per 100 m².** #### Why lead and lift matter - **Lead** is the distance from the source (quarry, market, store) to the work site. Transport cost rises with lead (it is paid per m³ or tonne per km, as per the district rate transport norms), so the same material has a different rate at different sites. - **Lift** is the vertical height through which material is raised above ground level, e.g. to upper floors. It needs extra labour or hoisting, so the cost rises with floor height. - Without lead and lift, the rate of the same item cannot be fixed fairly; they are added to the basic rate of the materials. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. For 100 m^2 of 12.5 mm plaster 1:3, what is the cement volume? A. 0.4167 m^3, as 1/3 of 1.25 m^3 B. 1.25 m^3, equal to wet mortar C. 0.1.. m^3, as 1/4 of wet mortar 0.3125 m^3 D. 0.3969 m^3, as 1/4 of dry mortar 1.5875 m^3 Answer: D. Wet = 100 x 0.0125 = 1.25 m^3, dry = 1.27 x 1.25 = 1.5875 m^3, cement = 1/4 of this. (Key point: Mortar quantities) 2. What changes in the rate analysis when the plaster is on a ceiling? A. Mortar ratio is made richer to 1:2 B. Lead is reduced to zero C. Labour is raised about 20-25% and staging cost is added D. Materials are increased by 25% but labour stays the same Answer: C. Overhead work reduces output and increases dropped mortar, so labour goes up and scaffolding/staging is added. (Key point: Ceiling modification) 3. What is lead in rate analysis? A. Vertical height through which material is raised B. Distance from the source of material to the work site C. Time taken to complete the work D. Quantity of material left after wastage Answer: B. Lead is the horizontal haul distance, and transport cost rises with it. (Key point: Meaning of lead) 4. Why is lift considered in rate analysis? A. Raising material to upper floors needs extra labour or hoisting, so cost rises with height B. It measures transport distance from the quarry C. It is the allowance for compaction D. It is the profit margin on upper floors Answer: A. Lift is vertical height above ground level and needs extra effort, so it is added to the basic material rate. 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