Sectional Views of Buildings for SS 3

Class: SS 3
Term: First Term
Week: 10
Age: 17 years
Duration: 60 minutes
Subject: Technical Drawing
Previous Lesson: Sections and Sectional Views, Revolved and Offset Sections
Topic: Sectional Views of Buildings
Subject Matter: Sectional view of buildings

Specific Objectives

By the end of the lesson, pupils/students should be able to:

Cognitive Domain

• Define a sectional view of a building.
• State the purpose of drawing sectional views.
• Identify the components visible in a building section.

Affective Domain

• Appreciate the importance of sectional views in architectural drawings.
• Demonstrate attention to detail and accuracy in drawing.

Psychomotor Domain

• Draw a sectional view of a simple building from given plans and elevations.
• Correctly represent different building materials and components in a section.

Social Domain

• Collaborate effectively during practical drawing activities.

Reference Materials

The following resources were used in planning this lesson:

• 2014 Senior Secondary Education Curriculum (SSEC)
• Relevant State Unified Scheme of Work
• A suitable Technical Drawing textbook for SS 3
• FCT ERC/NAPPS Scheme of work

Instructional Materials

The teacher will teach this lesson with the aid of:

• Building drawings (plans and elevations)
• Building models (physical or digital)
• Drawing instruments (drawing board, T-square, set squares, pencils, eraser, measuring rule)
• Drawing paper

Rationale for the Lesson

Understanding and drawing sectional views is fundamental in technical drawing, especially in the building industry. This skill allows students to visualise the internal structure and construction details of a building, which is crucial for effective communication between designers and builders. It also helps in identifying potential construction issues and ensuring structural integrity.

Prerequisite/Previous Knowledge

Students should have a good understanding of orthographic projections, including plans and elevations of buildings, and basic principles of dimensioning and scaling in technical drawing.

Lesson Content/Board Summary

Sectional Views of Buildings

Meaning of Sectional View

A sectional view, also known as a section, is a drawing that shows the internal features of an object or building as if it has been cut along an imaginary plane. For buildings, a sectional view reveals the construction details from the foundation to the roof, showing floor levels, wall thicknesses, roof structures, and the relationship between different building elements.

Purpose of Sectional Views

Sectional views are drawn for several important reasons:

1. To show the internal construction details of a building that cannot be clearly seen in plans or elevations.
2. To illustrate the vertical relationships between different parts of a building, such as floor heights, ceiling heights, and roof pitches.
3. To indicate the types of materials used in various components, like foundations, walls, floors, and roofs.
4. To provide critical information for contractors and builders during the construction process.
5. To aid in the calculation of quantities for materials and structural components.

The Cutting Plane

The cutting plane is an imaginary plane that is assumed to cut through the building to expose its interior. It is typically represented on the plan drawing by a long chain line, thicker at the ends and changes of direction, and labelled with letters (e.g., A-A, B-B). The direction of the arrows on the cutting plane line indicates the direction from which the section is viewed.

1. Position: The cutting plane is positioned to pass through significant features of the building, such as staircases, windows, doors, or structural elements, to reveal the most important details.
2. Direction: The view of the section is always taken perpendicular to the cutting plane, looking in the direction indicated by the arrows.

Components Shown in a Building Section

When a building is cut in section, the following components are typically visible and must be accurately represented:

1. Foundation: Footings, strip foundations, raft foundations, and their depths below ground level.
2. Walls: Thickness of external and internal walls, wall materials (e.g., blockwork, concrete), and their construction details.
3. Floor Levels: Ground floor, first floor, and subsequent floor levels, including floor slab thickness, finishes, and screeds.
4. Openings: Windows and doors, showing their sills, lintels, heads, and frames.
5. Roof Structure: Rafters, purlins, trusses, ceiling joists, roof covering (e.g., corrugated iron, tiles), and eaves details.
6. Ceilings: Ceiling finishes, ceiling heights, and any ceiling insulation.
7. Staircases: Treads, risers, landings, and handrails.
8. Services: Indication of plumbing pipes, electrical conduits, and ventilation ducts where they pass through the section.
9. Ground Line: The natural or finished ground level outside the building.

Principles of Drawing a Sectional View

To draw a sectional view of a building, follow these general principles:

1. Project from Plan: Project vertical lines from the cutting plane on the plan drawing to establish the width of the section.
2. Project from Elevation: Use the given elevations to determine the heights of various building elements (e.g., floor levels, window sills, lintels, roof ridge).
3. Draw Ground Line: Start by drawing the ground line and then the foundation details below it.
4. Draw Wall Lines: Project the wall lines from the plan and draw them up to the appropriate heights.
5. Add Floor and Roof Structures: Draw the floor slabs, roof timbers, and roof covering based on their heights and thicknesses.
6. Detail Openings: Include windows and doors at their correct positions and heights.
7. Hatching: Apply hatching (section lines) to all solid parts of the building that have been “cut” by the imaginary cutting plane. Different materials may have different hatching patterns.
8. Dimensioning and Labelling: Add key dimensions (e.g., heights, thicknesses) and labels for important components.

Teaching Methods/Instructional Techniques

Discussion, Demonstration, Guided Practice, Explanation, Question and Answer

Instructional Procedures

Step 1: Introduction

Time: 5 minutes

Teaching Skill: Review/Engagement

Teacher’s Activity: The teacher greets the students and reviews the previous lesson on orthographic projections (plans and elevations). The teacher then introduces the new topic, “Sectional Views of Buildings,” by asking students how they would show the inside of a building on a drawing.

Pupils’ Activity: Pupils respond to questions about previous knowledge and listen attentively to the introduction of the new topic.

Learning Point: Introduction to sectional views

Step 2: Explanation of Sectional View

Time: 10 minutes

Teaching Skill: Explanation/Demonstration

Teacher’s Activity: The teacher explains what a sectional view is, using a building model or a prepared drawing to illustrate how an imaginary cut reveals internal details. The teacher defines the cutting plane and its representation on a plan.

Pupils’ Activity: Pupils observe the demonstration, listen to the explanation, and ask clarifying questions.

Learning Point: Meaning of sectional view

Step 3: Purpose and Importance

Time: 8 minutes

Teaching Skill: Discussion/Explanation

Teacher’s Activity: The teacher discusses the various purposes and importance of sectional views in architectural and construction drawings, highlighting how they aid in understanding construction details and material specifications.

Pupils’ Activity: Pupils contribute to the discussion by suggesting reasons why sectional views are important and note down key points.

Learning Point: Purpose of sectional views

Step 4: Identifying Components in Section

Time: 10 minutes

Teaching Skill: Illustration/Identification

Teacher’s Activity: The teacher uses a detailed sectional drawing or model to point out and explain the various building components visible in a section, such as foundations, floor slabs, walls, roof structures, and openings.

Pupils’ Activity: Pupils identify and name the components as pointed out by the teacher, relating them to their knowledge of actual buildings.

Learning Point: Building components in section

Step 5: Demonstration of Drawing Principles

Time: 10 minutes

Teaching Skill: Demonstration/Modelling

Teacher’s Activity: The teacher demonstrates on the board or using a projector, the step-by-step process of drawing a simple sectional view from a given plan and elevation. Emphasis is placed on projecting lines, establishing heights, and applying hatching.

Pupils’ Activity: Pupils observe the drawing demonstration carefully, noting the techniques and principles applied by the teacher.

Learning Point: Drawing sectional views principles

Step 6: Guided Practice

Time: 5 minutes

Teaching Skill: Guided Practice

Teacher’s Activity: The teacher provides students with a simple plan and elevation and guides them to start drawing a sectional view, assisting with initial projections and establishing the ground line and foundation.

Pupils’ Activity: Pupils begin drawing the sectional view under the teacher’s guidance, applying the demonstrated principles.

Learning Point: Initial drawing practice

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

1. What is a sectional view of a building?
2. State two purposes of drawing sectional views.
3. Name three components typically shown in a building section.
4. How is the cutting plane indicated on a plan drawing?

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Understanding sectional views

Step 8: Note-Taking

Time: 10 minutes

Teaching Skill: Guided Writing

Teacher’s Activity: The teacher guides pupils/students to copy the essential Board Summary notes on sectional views of buildings into their notebooks.

Pupils’ Activity: Pupils/students copy the notes carefully into their notebooks.

Learning Point: Recording lesson notes

Step 9: Conclusion

Time: 2 minutes

Teaching Skill: Summarisation

Teacher’s Activity: The teacher summarises the key points of the lesson, reiterating the importance of sectional views in technical drawing and encourages students to practice drawing them.

Pupils’ Activity: Pupils listen to the summary and prepare for the next lesson.

Learning Point: Consolidation of learning

Continuous Assessment/Further Study

Type: Homework/Practice Exercise

Instruction: Using the provided plan and elevation of a simple building, draw a complete sectional view to a scale of 1:100. Ensure all major components are clearly represented and hatched correctly.

1. Draw the sectional view along the cutting plane A-A.
2. Label at least five major components visible in your section.
3. Apply appropriate hatching to all cut surfaces.

Lesson Keywords

• Sectional View – A drawing showing the internal features of an object or building as if cut.
• Cutting Plane – An imaginary plane that cuts through an object to reveal its interior.
• Hatching – Lines used to indicate surfaces that have been cut by the cutting plane.
• Orthographic Projection – A method of representing three-dimensional objects in two dimensions.

Differentiation

Support for struggling students: Provide simpler building plans with fewer details for their practice. Offer one-on-one guidance during the drawing process and provide pre-drawn outlines to complete. Focus on identifying major components before attempting full drawings.

Extension for advanced students: Challenge them to draw a more complex sectional view, perhaps including a staircase or a more intricate roof structure. Encourage them to research different hatching patterns for various building materials and apply them accurately.

Suggested Lesson Videos

For further understanding, students can search YouTube for “Sectional Views of Buildings Technical Drawing” or “How to draw building section”.