Quantity Surveying & Costing (Lab) (CE-505) - Unit 3 Short Notes

UNIT 3: DETAILED COST PLANNING, ANALYSIS & DIGITAL APPLICATION

I. MODULE 1: ADVANCED MEASUREMENT & TAKE-OFF TECHNIQUES (APPLIED)

A. Detailed Measurement for Complex Elements

• i. Measurement of Curved Walls, Sloped Roofs, and Irregular Foundations

  • Curved Walls: Measure girth (perimeter) at centerline for length. For area, use average length × height or divide into regular segments (arc segments, chords).

  • Sloped Roofs: Measure plan area first. Apply slope factor (from drawings or sec(θ) where θ is roof angle) to get true surface area.

    • Formula: True Area = Plan Area × Slope Factor

  • Irregular Foundations: Use grid method or trapezoidal rule on plan. For volumes, apply average end area or prismoidal formula for accuracy.

    • Prismoidal Formula (for 3D irregular solids):

$$V = \frac{L}{6} \left( A_1 + 4A_m + A_2 \right)$$

      where `L` = length between sections, `A1`, `Am`, `A2` = areas of two ends and mid-section.

• ii. Taking-off for MEP Services (Basic Quantities)

  • Ducting/Piping: Measure linear meters (LM) along centerline. Include fittings (elbows, tees) as "each" (nr) or by equivalent length from manufacturer tables.

  • Cable Trays: Measure LM of straight runs. Count support brackets (nr) separately.

  • Lighting/Outlets: Count number of units (nr) from electrical layouts. Note circuit lengths separately if required.

  • Key: Correlate with architectural reflected ceiling plans (RCP) and services layout drawings.

• iii. Measurement of Finishes for Non-Standard Areas

  • Atriums/Complex Geometries: Break down into simple geometric shapes (rectangles, triangles, circles). Measure each separately.

  • Walls with Openings: Measure gross wall area first. Deduct openings (doors, windows) only if SMM/NRM rule specifies (often for painting, not masonry).

  • Coved/Curved Corners: Measure girth of curve for length. For area, use radius × angle (in radians).

B. Application of Standard Methods of Measurement (SMM/NRM)

• i. Interpreting SMM/NRM Rules

  • SMM7 (UK) / NRM2 (UK) / CPWD (India): Each has specific rules for item descriptions, units of measurement, and inclusions/exclusions.

  • Example (Masonry): SMM might state "walls measured in m², excluding openings >0.5m²". Must check work section rules.

• ii. Preparing Item Descriptions & Grouping

  • Hierarchy: Section > Sub-section > Item.

  • Description Format: "BRICKWORK in walls, foundation, plinth, etc., in cement mortar 1:6" (includes material, location, mortar type).

  • Grouping: Group by material, location (e.g., "Basement", "Ground Floor"), or element (e.g., "External Walls").

• iii. Cross-referencing Drawings

  • Use drawing number, sheet number, detail reference (e.g., "Fig 3/A-02").

  • Checklist: Ensure every measured item has a drawing source. Mark measured areas on a paper or digital take-off sheet.

[!TIP] Exam Focus: Be prepared to interpret a rule from SMM/NRM and apply it to a given drawing detail. Common pitfall: applying the wrong unit (e.g., m³ instead of m² for a wall).

II. MODULE 2: COST PLANNING & ESTIMATING METHODOLOGIES (PRACTICAL)

A. Approaches to Building Cost Estimation

• i. Elemental Cost Planning (ECP) / Functional Unit Costing

  • Definition: Allocating cost to building elements (e.g., walls, roofs) or functional units (e.g., cost per m² of floor area, cost per bed in a hospital).

  • Formula: Elemental Cost = Elemental Quantity × Unit Rate

  • Benchmarking: Compare against industry cost guides (e.g., BCIS, RICS).

• ii. Comparative Cost Analysis

  • Use historical project data adjusted by cost indices (e.g., BCIS TPI - Total Price Index).

  • Formula for Current Cost Estimate:

$$\text{Current Cost} = \text{Historical Cost} \times \frac{\text{Current Index}}{\text{Historical Index}}$$

• iii. Approximate Quantities Method

  • For early design stages when drawings are schematic.

  • Measure gross areas/volumes from scaled drawings without deducting openings.

  • Apply "approximate" unit rates (higher than detailed rates to account for uncertainty).

B. Development of Detailed Estimates

• i. Allocating Unit Rates

  • Rate Breakdown: Material Cost + Labour Cost + Plant Cost + Overheads & Profit (%).

  • Source from catalogs, market surveys, or in-house databases.

• ii. Sourcing & Applying Unit Rate Data

  • Locality Adjustment: Rates vary by city/region. Apply location factor.

  • Inflation Adjustment: Update rates using cost indices (e.g., monthly WPI/CPI).

• iii. Preparation of Detailed BOQ

  • Structure:

    1. Preamble (Project details, measurement basis).

    2. Preliminaries/General Conditions (Site setup, supervision, etc.).

    3. Work Sections (Measured items with descriptions, quantities, unit rates, totals).

    4. Grand Summary (Total cost, contingencies, VAT).

  • Formatting: Use consistent decimal places, clear totals and subtotals.

C. Cost Planning for Different Project Stages

• i. Concept/Feasibility Stage:

  • Parametric Estimating: Cost = (Area × Rate/m²) + (Volume × Rate/m³).

  • Use broad cost models (e.g., "Residential building: ₹4,000-5,000/m²").

• ii. Design Development Stage:

  • Elemental Cost Plan: Prepare a detailed elemental breakdown.

  • Cost Check Exercises: Compare design proposals against the budget. Flag cost overruns.

• iii. Tender Stage:

  • Tender Document Cost Summary: Final BOQ becomes part of tender.

  • Include provisional sums, contingencies, and prime cost items.

[!TIP] Common Pitfall: Forgetting to include Preliminaries in early estimates, leading to significant under-estimation.

III. MODULE 3: LIFE CYCLE COSTING (LCC) & VALUE MANAGEMENT (VM) IN LAB CONTEXT

A. Fundamentals of Life Cycle Costing (LCC)

• i. Components of LCC

  • Initial Capital Cost (ICC): Construction cost.

  • Operation & Maintenance (O&M): Energy, cleaning, repairs.

  • Replacement Cost: Cost to replace components at end of life (e.g., roof, HVAC).

  • Residual Value (RV): Sale value at end of analysis period.

  • LCC Formula (Simplified):

$$\text{LCC} = \text{ICC} + \sum_{t=1}^{n} \frac{\text{O&M}_t}{(1+r)^t} + \sum \text{Replacement Costs} - \text{RV}$$

• ii. Discounting Cash Flows & NPV

  • Discount Rate (r): Reflects time value of money and risk (often client's MARR - Minimum Acceptable Rate of Return).

  • Net Present Value (NPV) for LCC: Sum of all discounted future costs (and revenues).

  • Formula for Present Value (PV) of a single future cost:

$$PV = \frac{FV}{(1+r)^n}$$

  where `FV` = future value, `n` = year.

• iii. Simple LCC Exercise

  • Example: Compare concrete roof (ICC high, O&M low, life 50 yrs) vs metal roof (ICC low, O&M high, life 25 yrs).

  • Steps:

    1. List all cash flows for each option over common analysis period (e.g., 50 yrs).

    2. Discount all future costs to present value using chosen r.

    3. Compare total LCC (NPV of costs). Choose lower LCC option.

B. Introduction to Value Management (VM) / Value Engineering (VE)

• i. VM Job Plan (8-Step or 5-Step)

  1. Information: Gather project data, costs, functions.

  2. Function Analysis: Identify primary functions (what the element does, not what it is). Use verb-noun format (e.g., "provide weather protection", "support load").

  3. Creative: Brainstorm alternative ways to achieve functions.

  4. Evaluation: Screen ideas based on function, cost, feasibility.

  5. Development: Develop selected ideas into detailed proposals with cost estimates.

  6. Presentation: Report to client/team.

• ii. Conducting Basic Function Analysis (Lab)

  • For a room: Functions = "Provide secure space", "Allow natural light", "Facilitate movement".

  • For a wall: Functions = "Support vertical loads", "Provide enclosure", "Insulate thermally".

  • Use function-cost matrix to see cost per function.

• iii. Identifying Cost Drivers & Savings

  • Cost Driver: Feature/component that significantly influences cost (e.g., floor-to-floor height, finish specification).

  • Savings without compromising function: e.g., Use standard door size instead of custom (same function: "provide access"), select alternative material with same performance (e.g., AAC blocks vs. clay bricks for "provide wall").

[!TIP] Exam Key: LCC is about long-term cost, not just construction cost. VM is about function, not cost-cutting. Be ready to differentiate them.

IV. MODULE 4: DIGITAL TOOLS & SOFTWARE APPLICATION (CORE LAB COMPONENT)

A. Quantity Take-Off (QTO) Software

• i. On-Screen Take-Off (OST)

  • Software: Bluebeam Revu, Planswift, On-Screen Takeoff, Trimble Accubid.

  • Process: Load PDF/DWG drawings. Calibrate scale.

• ii. Creating Measurement Layers & Calculating

  • Layers: Organize by element (e.g., "Foundation", "Walls", "Doors").

  • Tools:

    • Length: Measure linear items (pipes, walls).

    • Area: Measure surfaces (slabs, walls).

    • Count: Count objects (windows, lights, fixtures).

    • Volume: For 3D models or using area × depth.

• iii. Generating Take-off Reports

  • Report Types: Summary (by layer/category), Detailed (each measurement).

  • Export: To Excel or directly to estimating module.

  • Linking: Link measured items to cost database items (by matching description/code).

B. Cost Database Management

• i. Creating Item/Rate Library

  • Structure: Category > Sub-category > Item (e.g., "Masonry" > "Brickwork" > "Brickwork in 1:6 mortar").

  • Fields: Description, Unit, Material Cost, Labour Cost, Plant Cost, Overhead %, Profit %, Total Rate.

• ii. Updating Rates for Inflation/Locality

  • Method 1: Apply global adjustment factor (e.g., "Increase all rates by 5%").

  • Method 2: Use cost index multiplier:

  New Rate = Old Rate × (Current Index / Base Index)

  • Locality: Maintain separate databases or location factors for different cities.

• iii. Applying Resource Costs

  • Resource-Based Estimating: Break item into labour, material, plant components.

  • Software Feature: Assign resource units (e.g., "bricklayer - 0.5 hr/m²", "brick - 500 nr/m²") and resource rates to calculate total item rate.

C. Integrated Estimating & BOQ Generation

• i. Transferring Take-off Data

  • Direct Link: Some software (e.g., CostX, WinEst) allows direct transfer.

  • Indirect: Export take-off to CSV/Excel, then import into estimating module.

• ii. Formatting Standard BOQ Output

  • Preamble: Project name, QS, date, measurement basis.

  • Items: Auto-populated from take-off: Item No., Description, Unit, Quantity, Rate, Amount.

  • Grand Summary: Totals for each work section and overall total. Add contingency line.

• iii. Basic Report Generation

  • Generate cost comparison reports (e.g., "Option A vs Option B").

  • Graphs: Pie charts for cost distribution by element, bar charts for comparative analysis.

[!TIP] Lab Skill: Mastering keyboard shortcuts in OST software (e.g., W for wall, A for area) dramatically speeds up take-off. Always save layers and backup measurements.

V. MODULE 5: CONTRACTUAL & TENDER DOCUMENTATION (LAB EXERCISES)

A. Components of Tender Documents (QS Role)

• i. Preparing the Bill of Quantities (BOQ) as Tender Document

  • Form: Follow standard format (e.g., CESMM4, NRM2).

  • Content: Must be accurate, complete, and unambiguous. Include provisional sums and prime cost items clearly.

  • Status: "Priced" BOQ (contractor fills rates) or "Unpriced" (client provides for tendering).

• ii. Drafting Preliminaries/General Conditions

  • Items: Site accommodation, utilities, safety, insurance, supervision, temporary works.

  • Pricing: Can be lump sum or measured (e.g., "Site office - per month").

  • Reference: Based on standard conditions of contract (e.g., FIDIC, NEC, Indian Standard).

• iii. Understanding Standard Form of Tender

  • Structure: Cover page, instructions to tenderers, form of tender (signature block), schedule of rates (BOQ), appendices.

  • QS Role: Prepare BOQ and priced preliminaries to be inserted into the form.

B. Tender Analysis & Comparison (Lab Simulation)

• i. Receiving & Opening Mock Tender Returns

  • Process: Receive sealed bids (Excel/Paper BOQs). Open in presence of witnesses.

  • Check: Ensure all documents submitted, arithmetic accuracy (initial check).

• ii. Preparing Tender Comparison Statement

  • Tabulate: List all tenderers, their prices for each work section and total.

  • Rank: Order by total tender sum (lowest to highest).

  • Identify Anomalies: Flag extremely low/high prices for specific items (possible errors or unbalanced bids).

  • Arithmetic Check: Re-sum all tenderers' BOQs.

• iii. Basic Report on Tender Results

  • Content: List of tenderers, total prices, ranking, recommendation (usually lowest compliant tender).

  • Comment on: Completeness, any discrepancies, qualifications (conditions attached by tenderer).

  • Note: Report is for client's decision, not just lowest price.

[!TIP] Critical: The lowest tender is not always accepted. Check for compliance with specifications, qualifications, and financial standing. Report must highlight non-compliant tenders.

VI. MODULE 6: CASE STUDIES & INTEGRATED LAB PROJECTS

A. End-to-End Project Simulation

• i. From Drawings to Elemental Cost Plan

  • Input: Architectural drawings (plans, sections).

  • Process:

    1. Take-off gross floor areas, wall lengths, roof areas.

    2. Group into elements (Substructure, Superstructure, Finishes, Services).

    3. Apply elemental unit rates (from database/guides).

    4. Prepare Elemental Cost Plan table.

• ii. From Detailed Take-off to Priced BOQ

  • Input: Detailed working drawings.

  • Process:

    1. Detailed OST using SMM/NRM rules.

    2. Assign specific unit rates (not elemental averages).

    3. Price Preliminaries.

    4. Generate complete, priced BOQ.

• iii. Simple LCC Comparison on Selected Element

  • Example: Compare waterproofing system (Option A: Cementitious, Option B: Membrane).

  • Steps:

    1. Get ICC from BOQ rates.

    2. Estimate O&M (cleaning, repairs) and replacement (every 10 vs 15 yrs).

    3. Choose discount rate (e.g., 8%).

    4. Calculate LCC (NPV) for each over 30 years.

    5. Recommend based on lower LCC.

B. Critical Analysis of Completed Estimates

• i. Reviewing Cost Plans

  • Checklist:

    • Completeness: All elements included? Preliminaries?

    • Logic: Are elemental percentages reasonable? (e.g., Finishes ~10-15% of total building cost).

    • Compliance: Does measurement follow SMM/NRM? Are units correct?

• ii. Identifying Common Errors

  • Measurement: Double-counting, omitting deductions for openings, wrong units (m vs m²).

  • Rate Application: Using outdated rates, forgetting overheads/profit, applying wrong rate to item (e.g., using "brickwork in superstructure" rate for "below plinth").

  • Arithmetic: Summation errors, decimal mistakes.

• iii. Presenting Cost Plan Summary

  • Format: Executive summary (1 page) with:

    • Total estimated cost.

    • Cost per m².

    • Cost breakdown by major element (pie chart ideal).

    • Key assumptions & exclusions.

    • Comparison to budget (if any).

  • Delivery: Present as if to a client - clear, concise, focused on key figures and risks.

[!TIP] Final Exam Prep: Practice one full integrated exercise: Take-off a small building section → prepare BOQ → do a simple LCC on one element → present summary. This covers 80% of the unit's practical application.