Lesson Notes By Weeks and Term v3 - Senior Secondary 2
Elevation
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Elevation
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Subject: Building Construction
Class: Senior Secondary 2
Term: 1st Term
Week: 6
Theme: Building Drawing
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Read and in terpret building plans Draw elevationsfrom a given planof a bungalow.
wall face. (Teacher to draw Figure 1: A simple rectangular plan showing a front wall with one door in the centre and two windows, one on each side of the door.)
Figure 1: Simple Bungalow Floor Plan (Example) ``` _________________________ | | | | | [WINDOW] [DOOR] | [WINDOW] | | | | |_________________________| ^ | 6000 mm v ```
Note: Door is centrally placed, windows are equidistant from door and corners. Door centre at 5000mm from one end, windows centres at 2500mm and 7500mm.
Steps:
1. Prepare Drawing Sheet and Tools: Secure your drawing sheet on the drawing board. Ensure you have a T-square, set squares (30/60 and 45 degrees), pencils (HB, 2H, 2B), eraser, and measuring scale.
2. Establish Reference Lines: Ground Line (GL) / Finished Ground Level (FGL): Draw a long horizontal line across the lower part of your drawing sheet using a 2H pencil. This represents the Finished Ground Level (FGL). All heights are generally measured from here or from a reference datum related to it.
Damp Proof Course (DPC)
Level: Measure 150 mm (to scale) above the FGL and draw another light horizontal line.
Finished Floor Level (FFL): Measure 150 mm (to scale) above the DPC line (or 300 mm above FGL) and draw another light horizontal line. This will serve as a common datum for internal heights.
Eaves Level: Measure 3000 mm (to scale) above the FFL and draw a horizontal line. This represents the top of the wall plate before the roof structure begins.
3. Project Widths from the Plan: Position the plan above the intended elevation drawing space, ensuring the side you want to draw the elevation for is parallel to the ground line. Using your T-square and set square, project light vertical lines (using 2H pencil) downwards from all significant points on the plan that are visible from the front.
These points include: Outer corners of the building. Edges of door and window openings. Any other breaks or changes in the wall plane (e.g., columns, verandah edges). These vertical lines will define the horizontal extents of the building and its features on the elevation.
4. Draw the Main Walls: Darken the vertical projection lines corresponding to the outer corners of the building from the FGL up to the eaves level (using HB or H pencil). Connect these vertical lines at the FGL, DPC, FFL, and Eaves levels to form the basic outline of the building's walls.
5. Add Door and Window Openings: For the door: Darken the vertical projection lines defining the width of the door opening, from the DPC level up to the lintel level (FFL + 2100 mm). Connect the top of these vertical lines at the lintel level. Add a light horizontal line at the FFL to indicate the finished floor.
For the windows: Darken the vertical projection lines defining the width of each window opening. Measure 900 mm (to scale) from the DPC level upwards for the sill level and draw a horizontal line between the window's vertical lines. Measure 1200 mm (to scale) above the sill level for the lintel level and draw another horizontal line. Add basic window frame details within the opening (e.g., a cross to indicate glass, or horizontal/vertical members for a sash window).
6. Draw the Roof: Gable End: For a gable roof viewed from the front, the ridge (highest point) will be central. Find the centre point of the front wall at the eaves level.
Calculate the roof height: For a 30-degree pitch with a span of 6000 mm, the rise can be calculated using trigonometry (tan 30° = rise / (span/2)). `tan 30° = 0.577` `Rise = 0.577 (6000 mm / 2) = 0.577 3000 mm = 1731 mm` Measure 1731 mm (to scale) above the centre point of the eaves line. This is the apex (ridge) of the roof. From this apex, draw lines down to the outer corners of the wall at eaves level, extending outwards by the Calculate the roof height: For a 30-degree pitch with a span of 6000 mm, the rise can be calculated using trigonometry (tan 30° = rise / (span/2)). `tan 30° = 0.577` `Rise = 0.577 (6000 mm / 2) = 0.577 3000 mm = 1731 mm` Measure 1731 mm (to scale) above the centre point of the eaves line. This is the apex (ridge) of the roof. From this apex, draw lines down to the outer corners of the wall at eaves level, extending outwards by the eaves projection (600 mm). These form the sloping roof lines. Add fascia board (e.g., 200 mm deep) below the roof slope at the eaves.
7. Add Ground Details: Indicate the Finished Ground Level (FGL) with a bolder line, possibly showing a slight slope away from the building for drainage. Add steps if the FFL is significantly above the FGL.
8. Add Architectural Details and Dimensions: Include texture for wall finishes (e.g., horizontal lines for rendering, small rectangles for brickwork). Show rainwater goods like gutters and downpipes (if visible). Add dimensions for major heights (e.g., FGL to DPC, DPC to FFL, FFL to Eaves, Eaves to Ridge). Add centre lines for doors and windows. Label the elevation (e.g., "FRONT ELEVATION"). Specify the scale used (e.g., "Scale 1:100"). (Teacher should demonstrate this process on the board, either by sketching freehand or using basic drawing tools, emphasizing the projection lines and layering of details.)* --- 2.
1. Introduction to Elevations An elevation in building construction is an orthographic projection of the exterior (or interior) of a building, showing one face of the building as if viewed from a specific direction. It is a 2-dimensional drawing that depicts the vertical dimensions (heights) and the horizontal dimensions (widths) of the face being viewed. Unlike a plan (which shows a bird's-eye view looking down), an elevation shows how a building looks from the ground up. 2.
2. Types of Elevations Typically, four primary exterior elevations are drawn for a building: Front Elevation: The view of the building from its main entrance side. This is often the most detailed elevation as it usually features the primary architectural style and finishes.
Rear Elevation: The view of the building from its back.
Right Side Elevation: The view of the building from its right side when facing the front.
Left Side Elevation: The view of the building from its left side when facing the front. The choice of "front" is usually based on the orientation of the main entrance or the side facing the street. 2.
3. Information Conveyed by Elevations Elevations provide crucial information about a building's exterior, including: Heights: Overall building height, wall heights, roof pitch and height, window and door heights (sills and lintels), parapet heights, chimney heights, etc.
Widths: The horizontal dimensions of features as seen from that view.
Architectural Features: Windows, doors, roof forms (gable, hip, flat), verandahs, balconies, cornices, fascia boards, gutters, downpipes, steps, ramps, railings, decorative elements, and external finishes (e.g., brickwork, rendering, cladding).
Ground Line/Natural Ground Level (NGL): Indicates the existing ground level around the building.
Finished Ground Level (FGL): Indicates the final graded ground level around the building, which might be different from NG
L. Datum Line: A reference horizontal line (often the finished floor level of the ground floor) from which all vertical dimensions are measured. 2.
4. Relationship Between Plan and Elevation (Orthographic Projection) Elevations are derived directly from the building's floor plan through a process called orthographic projection.
Orthographic Projection: A method of representing 3D objects in 2D by projecting parallel lines from the object onto a projection plane. In building drawing, the plan view is typically placed above the elevations, and vertical lines are projected down from the plan to establish the widths of features on the elevation. Heights are then added based on the specified vertical dimensions of the building.
Key Principle: Every point or line on the plan corresponds to a vertical projection line that defines its position on the elevation. The width of any feature on an elevation is directly projected from its corresponding feature on the plan. 2.
5. Step-by-Step Guide to Drawing an Elevation from a Given Plan (Worked
Example: Drawing a Front Elevation of a Simple Rectangular Bungalow)
Given: A floor plan of a rectangular bungalow (Figure 1 - to be drawn on the board by teacher).
Overall length of the bungalow: 10,000 mm Overall width of the bungalow: 6,000 mm Wall thickness: 225 mm Door opening: 900 mm wide x 2100 mm high (DPC level to lintel level)
Window opening: 1200 mm wide x 1200 mm high (Sill height 900 mm from DPC level)
DPC (Damp Proof Course) level: 150 mm above Finished Ground Level (FGL)
Finished Floor Level (FFL): 150 mm above DPC level (making FFL 300 mm above FGL)
Wall height from FFL to eaves level: 3000 mm Roof type: Gable roof with a pitch of 30 degrees.
Overhang/Eaves projection: 600 mm from wall face. (Teacher to draw Figure 1: A simple rectangular plan showing a front wall with one door in the centre and two windows, one on each side of the door.)
Figure 1: Simple Bungalow Floor Plan (Example) ``` _________________________ | | | | | [WINDOW] [DOOR] | [WINDOW] | | | | |_________________________| ^ | 6000 mm v ```
Note: Door is centrally placed, windows are equidistant from door and corners. Door centre at 5000mm from one end, windows centres at 2500mm and 7500mm.* Steps:
1. Prepare Drawing Sheet and Tools: 3.
1. Teacher Activities Introduction (10 min): Introduce the topic "Elevation" and its significance in building construction using relevant examples of buildings in the local community. Ask students what they think an elevation drawing shows, building on their prior knowledge of plans. Briefly explain the objectives for the lesson.
Explanation of Key Concepts (20 min): Define "Elevation" and differentiate it from a "Plan." Explain the different types of elevations (front, rear, side) and what information each conveys. Introduce the concept of orthographic projection as the basis for drawing elevations from plans. Use a simple 3D object (e.g., a cuboid, or a building model if available) to demonstrate how different views are projected. Explain datum lines (FGL, DPC, FFL) and their importance for vertical measurements.
Demonstration (30 min): Using a prepared simple bungalow plan (e.g., the worked example in Section 2.5), demonstrate step-by-step how to draw a front elevation on the whiteboard or a large drawing board. Emphasize the use of projection lines from the plan and the application of given vertical dimensions. Show how to add key features like walls, windows, doors, and a simple roof (gable or hip). Stress neatness, accuracy, and appropriate line weights.
Guided Practice Setup (10 min): Distribute scaled printouts of a simple bungalow plan to each student or group. Provide clear instructions and specifications for drawing one elevation (e.g., the front elevation). Ensure students have their drawing instruments (T-square, set squares, pencils, scale ruler, drawing paper).
Supervision and Support (30 min): Circulate among students, providing individual guidance, correcting errors, and answering questions. Monitor their use of drawing tools and adherence to projection principles. Identify common mistakes (e.g., incorrect projection, wrong dimensions, poor line work) and address them collectively or individually.
Review and Conclusion (5 min): Review key takeaways of the lesson. Assign independent practice and hint at the next steps for subsequent lessons (e.g., drawing more complex elevations, adding rendering). 3.
2. Student Activities Active Listening and Participation: Students listen attentively to explanations and demonstrations, ask clarifying questions, and contribute to discussions.
Note-Taking: Students record key definitions, principles, and steps for drawing elevations.
Observation: Students observe the teacher's demonstration on the board, paying attention to the projection process and detailing.
Practical Drawing (Guided Practice): Students set up their drawing sheets and instruments. They practice drawing the specified elevation from the provided plan and specifications, following the steps demonstrated by the teacher. Students focus on accurately projecting lines, applying vertical dimensions, and representing architectural features.
Peer Learning: Students may be encouraged to work in pairs or small groups to discuss challenges and share drawing techniques.
Submission: Students submit their guided practice drawings for feedback. ---
Architectural Design and Client Communication: Elevations are the primary means for architects in Nigeria to communicate their design vision to clients. When a client wants to build a house in Ikoyi, Lekki, Abuja, or any other part of Nigeria, the architect presents elevations to show what the finished building will look like, facilitating discussions about aesthetics, materials, and overall appeal.
Statutory Approvals and Building Permits: Before any construction can commence in Nigeria, building plans, including detailed elevations, must be submitted to the relevant physical planning and development control agencies (e.g., Ministry of Physical Planning in states, FCDA in Abuja). These authorities scrutinize elevations to ensure compliance with zoning regulations, building codes (e.g., maximum height, setback distances), and aesthetic guidelines within the community. Without approved elevations, construction cannot legally proceed, preventing haphazard development. Construction Site Supervision and Quality Control: On a building site in Nigeria, the project engineer, foreman, or site supervisor constantly refers to the elevations. They use these drawings to verify that walls are being built to the correct height, windows and doors are installed at the specified levels, and roof pitches and overhangs match the design. This ensures that the constructed building accurately reflects the architectural intent and meets quality standards, whether it's a residential bungalow in Enugu or a commercial complex in Kano. ---