Introduction to Quantity Surveying

Quantity surveying (QS) involves the quantification, estimation, and costing of construction project works.
It focuses on controlling and managing construction costs.
Quantity Survey (QS): A schedule detailing quantities of all work items.
Quantity Surveyor (QS): A professional trained in construction quantification, costing, and contract procedures.
QS are crucial for life cycle costing, cost planning, procurement, tendering, contract administration, and commercial management.

Feasibility Study / Budget Determination: Estimates probable project cost before construction.
Data from quantification is used for tendering in the BOQ.
Construction cost components include materials, labor, transport, scaffolding, tools, overheads, taxes, and profit.
Estimates invite tenders and arrange contracts.
QS checks work progress; payments are based on actual measurements.

Drawings (complete and dimensioned): plans, elevations, sections, details.
Specifications: detailed descriptions of work quality, materials, proportions, and methods.
Rates: Unit rates for various works, materials, labor wages, and transportation.

Working drawings visually depict construction and function, providing details for elements and assembly (e.g., Floor Plans, Framing Plans, Foundation Plans).

Written stipulations for construction methods, workmanship standards, and material quality.
Example clauses cover water quality for concrete, concrete proportioning (e.g., Columns and footings: Class A $(1:2:4)$ ; Beams and slabs: Class A $(1:2:4)$ ), cement types, aggregate size ( $20-40 ext{ mm}$ ), and formwork requirements.

Round deformed bars for better concrete bond, free from rust/scale.
Must be accurately placed and tied at intersections with Gauge No. $16$ galvanized wire.
Conform to drawing size and spacing (e.g., $10 ext{ mm}$ bars at $0.80 ext{ m}$ on centers).

Exterior first-floor walls: at least $150 ext{ mm}$ thick; interior walls: generally $100 ext{ mm}$ , but $150 ext{ mm}$ if plumbing is present.
Above first floor: $100 ext{ mm}$ unless specified otherwise.
Cells filled with cement mortar ( $1:3$ by volume).
Reinforced with $10 ext{ mm}$ deformed bars, spaced not more than $0.80 ext{ m}$ on centers, both ways.
Finishes to follow elevations (e.g., cement plaster $1:1:3$ for CHB walls).

Specified materials for various rooms (e.g., Entrance Porch, Living Room, Kitchen).

Unit rates for each work item are essential for estimating, considering material costs, transport, and labor wages.

The process of converting drawn information into descriptions and quantities through measurement, counting, or approximation following specific rules. Accuracy is crucial.

Applying cost-estimating techniques to determine the approximate project cost, varying with available information.

Preliminary/Approximate Estimate: Quick cost idea for decision-making, based on similar works or area methods.
Detailed Estimate: Prepared after approval, before tendering; subdivides project for quantity calculation from drawings.
Quantity Estimates: Complete quantities for project implementation.
Revised Estimate: Prepared if estimate exceeds by >5% due to changes.
Maintenance Estimate: For maintenance quantities and costs.

A quantitative assessment of likely resource costs for project activities, including basis, assumptions, inclusions, and exclusions. Expressed in currency units.

PRICE: What you pay for goods/services.
COST: Total input resources (materials, labor, transport, taxes). Direct Cost + Indirect Cost (Overhead + Contingencies).
VALUE: What you get; Direct Cost + Indirect Cost + Profit = Contract Price.

Clarify discrepancies between plans and specifications with the architect/engineer.
Maintain orderly, systematic computations, recorded for easy checking and reuse (e.g., for CHB, reinforcement).

Competitive Bidding: Price-dominant, multiple qualified suppliers, standard items.
Negotiation: Broad performance factors, higher buyer input, complex items, higher volume.

Typically includes Approved Budget for the Contract (ABC), bid reference, duration, scope. Open to qualified bidders; procurement via open competitive bidding (e.g., per RA 9184).
Bidding documents available for purchase/download; pre-bid conferences, submission deadlines, bid opening, security, and post-qualification procedures are common. Right to reject bids reserved.

ITB outlines procedures for bid submission (dates, times, meetings, requirements). Section II covers eligibility, submission, evaluation, and award. BDS provides procurement-specific conditions. Performance, payments, and risks are in GCC/SCC.

Formalizes the contract, incorporating all documents by reference, stating contract sum and time. Documents have a priority order to resolve conflicts.

Single contract: General contractor manages entire project, including subcontracts. Simplifies coordination but shifts risk to GC.
Separate contracts: Owner creates separate agreements for project portions. Can lower owner's coordination burden but requires strong project management, possibly by an external firm.