By the end of this chapter, you will be able to:
Mastering these skills will help you manage contracts confidently and ensure successful project outcomes in your trade.
Preparation of contract documents is a foundational phase in quantity surveying that directly influences the clarity, enforceability, and successful execution of construction projects. In Kenya, where projects often involve multiple stakeholders such as contractors, consultants, and government agencies, precise contract documentation mitigates disputes and enhances cost control. This chapter focuses on two critical elements: the preparation of working drawings and work specifications. Both components serve to communicate the technical and qualitative requirements of the project, ensuring all parties have a shared understanding of the scope and standards expected.
Working drawings form the visual and technical blueprint of a construction project. They translate the architectural and engineering designs into detailed instructions that guide contractors and suppliers. For quantity surveyors in Kenya, accurate working drawings are indispensable for cost estimation, procurement planning, and contract administration.
The purpose of working drawings extends beyond mere illustration; they are legal documents that underpin contract obligations. Firstly, they provide detailed dimensions and layouts that help contractors understand the exact requirements. Secondly, they facilitate precise quantity take-offs, which are essential for accurate cost estimation and tendering. Thirdly, working drawings ensure compliance with statutory regulations such as the National Construction Authority (NCA) standards and local building codes enforced by county governments. Fourthly, they serve as a reference point during construction to verify that work is executed according to design. Lastly, these drawings assist in coordinating various disciplines, such as electrical, plumbing, and structural elements, reducing conflicts and rework.
Working drawings encompass several types, each serving distinct functions within the project lifecycle. First, architectural drawings illustrate the spatial arrangement, finishes, and aesthetics of the building. Second, structural drawings detail the framework, including columns, beams, and foundations, critical for ensuring safety and durability. Third, mechanical and electrical drawings specify installations such as HVAC systems, wiring, and plumbing, which impact material quantities and labor costs. Fourth, civil engineering drawings cover site works like roads, drainage, and earthworks, which are vital for site preparation cost assessments. Finally, shop drawings, often produced by contractors or suppliers, provide fabrication details for specific components, ensuring that off-site manufacturing aligns with project requirements.
The preparation of working drawings is a collaborative and iterative process involving architects, engineers, and quantity surveyors. Initially, conceptual designs are developed and reviewed for feasibility regarding cost and constructability. Next, detailed drawings are produced, incorporating all necessary technical specifications and dimensions. These drawings undergo rigorous checks for accuracy, compliance, and coordination among disciplines. Following approval, the drawings are issued as part of the tender documents. Throughout construction, working drawings may be updated to reflect approved variations or site instructions, which the quantity surveyor must track for contract administration and valuation purposes.
Preparing working drawings involves challenges that can lead to project delays or cost overruns if not addressed. One common challenge is incomplete or ambiguous drawings, which create confusion during tendering and construction. Another is poor coordination between disciplines, resulting in clashes such as electrical conduits conflicting with structural elements. Third, non-compliance with regulatory standards can cause rejections during approvals by county authorities. Fourth, frequent design changes during construction disrupt workflow and complicate cost control. Lastly, limited access to digital tools or expertise in some Kenyan firms can hinder efficient drawing preparation.
Explain five reasons why working drawings are critical in quantity surveying for construction projects in Kenya. (10 marks)
Describe the main types of working drawings and how each influences the quantity surveyor’s role during tendering and construction. (15 marks)
Outline six steps involved in the preparation of working drawings and discuss why each step is important. (15 marks)
Identify four common challenges faced during the preparation of working drawings and suggest appropriate mitigation measures for each. (10 marks)
Create a free account to open more of this chapter.
Free: practical guides, quick cards, workplace scenarios and more.
Create a free accountThis chapter covered the essential elements involved in preparing contract documents for construction projects. It began with the preparation of working drawings, which provide detailed visual representations necessary for accurate project execution. Work specifications were then discussed, outlining the technical requirements and standards that guide construction activities. The bill of quantities was explained as a detailed itemization of materials and labor required, forming the basis for cost estimation. Preparation of the schedule of rates followed, detailing unit prices for various work components to facilitate financial planning. Conditions of contract were examined to establish the legal and operational framework governing the project. The chapter also explored different forms of agreement and tender documents that formalize commitments between parties. Finally, various types of construction contracts were described, including lump sum, serial contracting, negotiated, labour-based, BOT/BOOT, and EPC/turnkey contracts, each suited to different project needs and risk allocations.
Type: Individual
| Tools & Equipment | Materials |
|---|---|
| Drawing board | Tracing paper A3 size |
| T-square | Reference structural design brief |
| Set squares (45° and 60°) | |
| Mechanical pencil 0.5mm | |
| Eraser | |
| Scale ruler (metric) | |
| Tracing paper A3 size | |
| Set of technical pens (0.1mm, 0.3mm, 0.5mm) | |
| Calculator |
| S/N | Item | Quantity |
|---|---|---|
| 1 | Drawing board | 1 Pc per Candidate |
| 2 | T-square | 1 Pc per Candidate |
| 3 | Set squares (45° and 60°) | 1 Set per Candidate |
| 4 | Mechanical pencil 0.5mm | 1 Pc per Candidate |
| 5 | Eraser | 1 Pc per Candidate |
| 6 | Scale ruler (metric) | 1 Pc per Candidate |
| 7 | Tracing paper A3 size | 5 Sheets per Candidate |
| 8 | Set of technical pens (0.1mm, 0.3mm, 0.5mm) | 1 Set per Candidate |
| 9 | Calculator | 1 Pc per Candidate |
| 10 | Reference structural design brief | 1 Set per Candidate |
| Items to be Evaluated | Marks Available | Marks Obtained | Comments |
|---|---|---|---|
| TASK 1: Preparation and Layout of Working Drawings | |||
| Used appropriate PPE as per occupational safety and health regulations (Award 1 mark for each correct PPE worn: helmet, safety boots, reflective jacket) | 3 | ||
| Assembled all required drawing tools and materials before starting (Award 0.5 mark for each of 4 correct tools/materials assembled) | 2 | ||
| Interpreted the design brief accurately to determine beam dimensions and reinforcement details (Award 1 mark each for correct length, width, and depth identification) | 3 | ||
| Set out drawing borders and title block correctly on A3 tracing paper (Award 1 mark for neat borders, 1 mark for correct title block details) | 2 | ||
| Drew the plan view of the beam accurately to scale (Award up to 4 marks based on accurate length and width dimensions and neatness) | 4 | ||
| Drew the elevation and section views showing correct beam depth and reinforcement positions (Award 2 marks each for elevation, section, and reinforcement detail accuracy) | 6 | ||
| Added all required dimension lines and annotations clearly and correctly (Award 1 mark each for length, width, depth dimensions and reinforcement annotations) | 4 | ||
| Used appropriate line weights and technical pen sizes for clarity (Award 1 mark for correct line weights, 1 mark for neat penmanship) | 2 | ||
| Checked drawing for accuracy and completeness before submission (Award 2 marks for thorough checking and corrections) | 2 | ||
| Cleaned and stored drawing tools and materials properly after completion (Award 1 mark each for cleaning and proper storage) | 2 | ||
| Sub-Total | 30 | ||
| PRODUCT CHECKLIST | |||
| Beam length dimension accurately shown as 3000mm ± 10mm (Award 3 marks for correct dimension within tolerance) | 3 | ||
| Beam width dimension accurately shown as 300mm ± 5mm (Award 3 marks for correct dimension within tolerance) | 3 | ||
| Beam depth dimension accurately shown as 500mm ± 5mm (Award 3 marks for correct dimension within tolerance) | 3 | ||
| Reinforcement details clearly annotated (e.g. 4Y16 main bars, R10 links @ 150 c/c) (Award 5 marks for complete and correct reinforcement annotations) | 5 | ||
| Drawing shows plan, elevation, and section views with correct scale and proportions (Award 6 marks for all views correctly drawn and scaled) | 6 | ||
| Drawing is neat, legible, and professionally presented (Award 5 marks for overall neatness and presentation quality) | 5 | ||
| All dimension lines and annotations are clear, correctly placed and unambiguous (Award 5 marks for clarity and correctness of dimensions and annotations) | 5 | ||
| Sub-Total | 30 | ||
| GRAND TOTAL | 60 | ||
Type: Individual
| Tools & Equipment | Materials |
|---|---|
| Measuring Tape (5m) | Reference Standards Manual (e.g. KEBS Building Standards) |
| Pen | |
| Notebook or Specification Template | |
| Calculator | |
| Ruler or Scale |
| S/N | Item | Quantity |
|---|---|---|
| 1 | Measuring Tape (5m) | 1 Pc per Candidate |
| 2 | Pen | 1 Pc per Candidate |
| 3 | Notebook or Specification Template | 1 Pc per Candidate |
| 4 | Reference Standards Manual (e.g. KEBS Building Standards) | 1 Pc per Candidate |
| 5 | Calculator | 1 Pc per Candidate |
| 6 | Ruler or Scale | 1 Pc per Candidate |
| Items to be Evaluated | Marks Available | Marks Obtained | Comments |
|---|---|---|---|
| TASK 1: PREPARATION AND DRAFTING OF WORK SPECIFICATIONS | |||
| Identified and used appropriate PPE (e.g. helmet, safety boots, reflective vest) (Award 1 mark for each correct PPE worn) | 3 | ||
| Assembled all required tools and materials before starting drafting (Award 0.5 mark each for assembling 4 tools/materials) | 2 | ||
| Reviewed project brief and reference standards for compliance (Award 3 marks for thorough review and understanding) | 3 | ||
| Measured and noted key dimensions of the house (12,000mm x 9,000mm) (Award 3 marks for accurate measurement and recording) | 3 | ||
| Drafted clear and detailed material specifications for walls, roofing, flooring, finishes, and fixtures (Award 1 mark for each correctly specified material item, total 8 marks) | 8 | ||
| Outlined workmanship standards including workmanship quality, tolerances, and installation procedures (Award 1 mark for each correctly described workmanship standard, total 6 marks) | 6 | ||
| Organized the specification document logically and legibly (Award 3 marks for neatness and logical structure) | 3 | ||
| Sub-Total | 28 | ||
| PRODUCT CHECKLIST | |||
| Work specification document includes all materials with correct types and quality standards (Award 2 marks for each major material category correctly specified: walls, roofing, flooring) | 6 | ||
| Workmanship standards clearly outlined including tolerances and installation procedures (Award 5 marks for complete and clear workmanship standards) | 5 | ||
| Document includes correct and consistent dimensions for the house (12,000mm x 9,000mm) (Award 4 marks for accurate and consistent dimensioning) | 4 | ||
| Final work specification document is neat, complete, and professionally presented (Award 3 marks for overall neatness and professionalism) | 3 | ||
| Sub-Total | 18 | ||
| GRAND TOTAL | 46 | ||
At the start of this chapter we promised you would be able to:
Tick each one you can genuinely do.
So, are you there yet?
You're competent when you can confidently do 50% or more of what this chapter promised.
Sign in to record how you're doing.