Lesson Notes By Weeks and Term v3 - Senior Secondary 2
Building design and working Drawing
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Building design and working Drawing
Download the Lessonotes Mobile Nigeria 2025 app for faster lesson access on Android and iPhone.
Subject: Technical Drawings
Class: Senior Secondary 2
Term: 1st Term
Week: 10
Theme: Building And Engineering Design And Drawing
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Design buildings with one floor to meet given specifications. Prepare working drawings from sketches.
This section details the core components of building design and working drawings, essential for teachers to convey to students. 2.1 Building Design Building design is the holistic process of creating a plan for a building, taking into account its functional, aesthetic, structural, and economic requirements. It involves translating a client's needs into a practical and constructible solution. Factors Influencing Building Design (Nigerian Context): Client Brief/Requirements: The number of rooms, specific functions (e.g., living, dining, kitchen, bedrooms, toilets, store), desired finishes, and budget. For example, a typical Nigerian family might prioritize a large living area and a spacious kitchen with an attached store.
Site Analysis: Topography, soil conditions, orientation (for optimal ventilation and natural light given Nigeria's tropical climate), access roads, existing features, and surrounding environment.
Local Building Codes and Regulations: Adherence to urban planning standards, setback requirements (distances from boundaries), permissible building heights, and material specifications enforced by local government authorities (e.g., Lagos State Physical Planning Permit Authority, Abuja Metropolitan Management Council).
Climatic Considerations: Design for natural ventilation (cross-ventilation), shading (e.g., wide eaves, verandas common in Nigerian architecture), and protection from heavy rainfall and intense sunlight.
Material Availability and Cost: Utilizing locally sourced materials like cement blocks, timber, and roofing sheets, which often influence design choices and construction costs in Nigeria.
Functionality and Circulation: Efficient arrangement of spaces for ease of movement, privacy, and logical flow (e.g., direct access from kitchen to dining, bedrooms located away from public areas).
Aesthetics: The visual appeal of the building, including its form, style, and integration with the environment.
Stages of Design:
1. Conceptualization (Sketch Design): Initial freehand sketches exploring various ideas based on the client brief and site analysis. Focus is on spatial relationships and overall form.
2. Preliminary Design: More refined sketches or basic scaled drawings showing floor plans, elevations, and possibly sections. This stage helps to finalize the general layout and appearance.
3. Detailed Design: Development of comprehensive working drawings that provide all information required for construction. 2.2 Working Drawings Working drawings are a set of detailed graphical representations that provide all the necessary information for the construction of a building. They are a universal language used by architects, engineers, and builders, serving as a legal document.
Importance of Working Drawings: Communication: Clearly conveys the design intent to all stakeholders.
Error Reduction: Minimizes misunderstandings and costly mistakes during construction.
Cost Estimation: Enables accurate quantity surveying and budgeting.
Quality Control: Serves as a benchmark for checking the quality of work.
Legal Document: Forms part of the contract between the client and the builder.
Types of Working Drawings:
1. Floor Plan: A horizontal section cut through the building, typically at 1.2m above the finished floor level, looking downwards.
It shows: Layout of rooms and spaces. Dimensions (overall and individual elements). Positions and types of doors and windows. Built-in fixtures (e.g., sanitary fittings, kitchen cabinets). Wall thicknesses and material indications. Room labels and floor finishes. Staircases (if applicable).
Conventions: Walls shown as thick lines, doors as arcs representing swing, windows as thin lines with specific symbols. Dimension lines should be clear and outside the main drawing.
2. Elevations: Orthographic projections showing the exterior appearance of each side of the building (Front Elevation, Rear Elevation, Left Side Elevation, Right Side Elevation).
They show: Vertical dimensions (heights of walls, windows, doors, roof apex). Exterior finishes and materials. Roof profile and overhangs. Ground lines and finished floor levels.
Conventions: Ground line shown as a thick, dark line. Features like windows and doors are projected directly from the floor plan.
3. Sections: Vertical cuts through the building, revealing its internal construction details.
They show: Wall, floor, and roof structural elements. Foundation details. Vertical dimensions and heights. Relationships between different floor levels.
Conventions: The cutting plane line (chain line with arrows) on the floor plan indicates where the section is taken and the direction of view.
4. Site Plan: Shows the building's location within its plot, including: Boundaries and dimensions of the plot. Setbacks (distance like windows and doors are projected directly from the floor plan.
3. Sections: Vertical cuts through the building, revealing its internal construction details.
They show: Wall, floor, and roof structural elements. Foundation details. Vertical dimensions and heights. Relationships between different floor levels.
Conventions: The cutting plane line (chain line with arrows) on the floor plan indicates where the section is taken and the direction of view.
4. Site Plan: Shows the building's location within its plot, including: Boundaries and dimensions of the plot. Setbacks (distance from building to property lines). Access roads, pedestrian paths, and parking areas. Existing and proposed landscaping. Utility connections (water, sewage, electricity). North point.
Conventions: Often drawn at a smaller scale (e.g., 1:200, 1:500) than floor plans.
5. Foundation Plan: Details the type and dimensions of the building's foundation, including: Footings, trenches, and concrete slab details. Reinforcement details (if applicable). Setting out dimensions.
6. Roof Plan: Shows the layout of the roof, including: Roof shape, slopes, and ridges. Drainage points (gutters, downpipes). Roofing material. Overhangs.
Conventions: Often includes directions of roof fall.
7. Electrical Layout: Indicates positions of electrical fittings (switches, sockets, light points, distribution board).
8. Plumbing Layout: Shows the routing of water supply and waste disposal pipes, and positions of sanitary fixtures.
Drawing Standards and Conventions: Lines: Continuous Thick Line: For visible outlines, cut sections (e.g., walls in a floor plan).
Continuous Thin Line: For dimension lines, projection lines, hatching, short break lines.
Dashed Line (Hidden Line): For hidden features or features above the cutting plane.
Chain Line (Long-Dashed Dot Line): For centre lines, cutting planes, and boundaries.
Scales: Ratios representing the relationship between the drawing size and the actual object size.
Common scales: 1:100: 1 unit on the drawing represents 100 units in reality (e.g., 1cm = 1m). Common for floor plans, elevations, sections. 1:50: More detailed, 1 unit on drawing = 50 units in reality (e.g., 2cm = 1m). Used for detailed plans, larger scale sections. 1:200 or 1:500: For site plans and block plans. Teacher should demonstrate how to use a scale rule.
Dimensioning: Placing numerical values (in millimetres or metres) to indicate lengths, widths, and heights. Should be clear, concise, and placed outside the drawing features. Units (mm or m) should be consistent or clearly stated. Arrowheads or slashes at the ends of dimension lines.
Symbols: Standardized graphical representations for doors, windows, sanitary fittings, electrical fixtures, etc. (e.g., WC, sink, light switch).
Lettering: Clear, legible, and uniform lettering (uppercase or architectural style) for labels, titles, and notes.
Title Block: A block of information typically located at the bottom right corner of a drawing sheet, containing: Project Title, Drawing Title, Scale, Date, Drawn By, Checked By, Sheet Number, Revisions, Company/School Name. Worked
Example: Designing a Simple Single-Floor Building Client Brief: A two-bedroom flat for a small family in Lagos.
Requirements: Living Room, Dining Area, Kitchen, Store, 2 Bedrooms (one master with ensuite toilet/bath), 1 Common Toilet/Bath.
Approximate Sizes: Living (4.0m x 4.5m), Dining (3.0m x 3.0m), Kitchen (3.0m x 3.0m), Master Bedroom (3.5m x 4.0m), Second Bedroom (3.0m x 3.5m).
Site: Relatively flat, with road access from the front.
Step-by-Step Design Process:
1. Conceptual Sketch (Teacher Demonstration): Start with a rough bubble diagram or freehand sketch to arrange the spaces logically. Place public areas (Living, Dining, Kitchen) towards the front/easily accessible side. Locate private areas (Bedrooms, Toilets) away from public gaze.
Consider circulation: minimize long corridors, ensure easy access between related spaces. Group wet areas (kitchen, toilets) to simplify plumbing.
Sketch example: ``` ------------------------------------------------ | Living Room | Dining | Kitchen | Store | | | | | | | | | | | |-------------+--------+---------+-------| | Common T/B | Corridor | | | | |-------------+--------------------------| | Bedroom 2 | Master Bedroom | | | Ensuite T/B | | | | ------------------------------------------------ ```
2. Developing a Scaled Floor Plan (Teacher Guides): Drawing Board Setup: Secure drawing away from public gaze.
Consider circulation: minimize long corridors, ensure easy access between related spaces. Group wet areas (kitchen, toilets) to simplify plumbing.
Sketch example: ``` ------------------------------------------------ | Living Room | Dining | Kitchen | Store | | | | | | | | | | | |-------------+--------+---------+-------| | Common T/B | Corridor | | | | |-------------+--------------------------| | Bedroom 2 | Master Bedroom | | | Ensuite T/B | | | | ------------------------------------------------ ```
2. Developing a Scaled Floor Plan (Teacher Guides): Drawing Board Setup: Secure drawing sheet with masking tape, ensure T-square is flush.
Establish Grid/Main Walls: Using a chosen scale (e.g., 1:100), start drawing the main perimeter walls. Assuming 225mm (0.225m) thick block walls common in Nigeria.
Internal Walls: Draw internal partition walls (e.g., 150mm/0.150m thick).
Room Layout & Dimensions: Accurately measure and draw the rooms according to the approximate sizes.
Example: Living Room 4.0m x 4.5m.
At 1:100 scale, this is 4.0cm x 4.5cm.
Doors and Windows: Indicate door openings (e.g., 900mm wide for main doors, 750mm for internal, 600mm for toilets). Draw symbols for single swing doors. Indicate window openings (e.g., 1200mm wide x 1200mm high for living/bedrooms, 600mm x 600mm for toilets). Draw window symbols. Ensure doors open into rooms, not blocking circulation or other doors/furniture.
Fixtures: Draw symbols for WC, wash hand basin (WHB), shower, kitchen sink.
Dimensioning: Add overall dimensions and specific dimensions for room widths/lengths, window/door positions.
Labelling: Label all rooms (e.g., LIVING ROOM, KITCHEN, BEDROOM 1, etc.) and add the scale (e.g., SCALE 1:100).
Title Block: Fill in the title block with relevant information.
3. Extracting an Elevation from the Floor Plan (Teacher Demonstrates): Projection: Use the T-square and set squares to project vertical lines upwards from the floor plan, corresponding to all wall lines, door openings, and window openings.
Establish Ground and Floor Levels: Draw a thick ground line. Draw the finished floor level (FFL) line (e.g., 150mm above ground level).
Wall Heights: Draw the top of the wall line (e.g., 2.8m or 3.0m above FFL, common in Nigeria).
Door/Window Heights: Draw the top and bottom lines for doors and windows based on standard heights (e.g., door head at 2.1m, window sills at 1.2m above FFL).
Roof Line: Sketch the roof profile (e.g., a simple gable or hip roof common for single-floor flats in Nigeria), showing the eaves overhang.
Details: Add features like steps, veranda (if designed), and any decorative elements.
Dimensions: Add vertical dimensions (e.g., wall height, window height, sill height).
Labelling: Label the elevation (e.g., FRONT ELEVATION).
Teacher Activities: Introduction (10 mins): Introduce the topic "Building Design and Working Drawings" by asking students about the difference between a house and a building plan. Discuss the importance of proper planning before construction, using examples of well-planned versus poorly planned structures in Nigerian communities.
Briefly review relevant prior knowledge: orthographic projection, basic drafting tools, types of lines, and scales.
Concept Explanation (30 mins): Explain "Building Design" thoroughly, emphasizing factors like client brief, site analysis, local building codes (e.g., minimum setbacks in urban areas), and climatic considerations (e.g., cross-ventilation for Nigeria's hot climate). Define "Working Drawings" and explain their critical role in construction. Systematically explain each type of working drawing (Floor Plan, Elevations, Sections, Site Plan, etc.) using visual aids like sample plan charts, projector, or pre-drawn examples.
Detail drawing standards and conventions: types of lines, common scales (1:100, 1:50, 1:200), dimensioning rules, and standard symbols for doors, windows, and sanitary fittings. Demonstrate the use of a scale rule.
Worked Example Demonstration (45 mins): Present the client brief for a simple two-bedroom flat (as detailed in the Key Concepts section).
Step 1: Conceptual Sketch: On the chalkboard or a large drawing board, demonstrate how to create a freehand conceptual sketch/bubble diagram to arrange spaces logically, considering flow and privacy.
Step 2: Floor Plan Development: Guide students through drawing the floor plan at a specified scale (e.g., 1:100). Start by establishing the perimeter walls. Then internal walls. Accurately measure and draw rooms according to specified dimensions. Demonstrate drawing door and window symbols with correct orientation. Show how to add fixtures (WC, WHB, kitchen sink). Demonstrate clear dimensioning and room labelling. Emphasize neatness and accuracy.
Step 3: Elevation Extraction: Demonstrate how to project lines from the developed floor plan to generate a front elevation. Show how to establish ground level, finished floor level, and wall heights. Project and draw doors, windows, and roof lines. Add vertical dimensions.
Guided Practice Instruction (15 mins): Introduce Guided Practice questions. Circulate among students, providing individual assistance and feedback as they begin working on the practice questions. Encourage peer discussion and problem-solving.
Student Activities: Active Listening and Note-Taking: Students will listen attentively to explanations and take detailed notes on key concepts, definitions, and drawing conventions.
Participate in Discussion: Students will contribute to discussions by asking questions and sharing their understanding of building design principles, especially those relevant to their local environment.
Sketching Exercises: Students will practice freehand sketching of basic room layouts and building forms to develop conceptual design skills.
Drafting Practice: Students will practice drawing various types of lines, lettering, and standard symbols using their drawing instruments (T-square, set squares, pencils, scale rule).
Guided Drawing: Following the teacher's demonstration, students will attempt to draw elements of the worked example (e.g., a single room's floor plan, then progressively the full plan, and finally an elevation) using their drawing boards and instruments, to scale.
Questioning: Students will ask clarifying questions during the demonstration and practice sessions to deepen their understanding.
Career Pathways in the Nigerian Construction Industry: This topic directly links to numerous professional roles vital for Nigeria's development. Students gaining proficiency in building design and working drawings can pursue careers as: Architectural Technologists/Draughtsmen: Working with architectural firms in major cities like Lagos, Abuja, Port Harcourt to produce detailed construction drawings for residential, commercial, and public buildings.
Site Supervisors/Foremen: On construction sites across Nigeria, understanding working drawings is crucial for interpreting plans, managing tradesmen, and ensuring construction adheres to specifications.
Building Contractors: Small and medium-scale contractors in Nigeria often need to produce or interpret simple working drawings for clients and regulatory bodies.
Estate Developers: For planning and executing new housing estates or commercial complexes, requiring a thorough understanding of design and construction documentation. Community Development and Personal Projects: Local Community Projects: Students can apply their knowledge to assist in planning and drafting simple designs for community infrastructure like market stalls, primary health centers, or public toilets, especially in rural or developing urban areas where professional services might be less accessible.
Home Renovations/Extensions: Individuals can use their skills to sketch plans for personal home renovations or extensions, allowing them to communicate effectively with artisans and manage their projects more efficiently, saving costs on professional fees for minor alterations.
Interpreting Building Plans: Enables citizens to understand building plans presented for public review, or plans for their own properties, promoting informed decision-making and participation in local planning processes.
Economic Empowerment and Entrepreneurship: Self-Employment: With strong drafting skills, students can become freelance draughtsmen, offering services to individuals or small businesses needing building plans, thus contributing to the local economy and creating self-employment opportunities. This is particularly relevant in Nigeria where many individuals engage in informal construction or small-scale development.
Value Chain Participation: Understanding design and drawings helps students integrate into the broader construction value chain, from material suppliers (who need to interpret material lists from drawings) to real estate agents (who need to understand property layouts).