Lesson Notes By Weeks and Term v5 - Grade 11

Lesson Video

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Performance objectives

• Define key terms like floor plans, elevations, and sections.
• Identify different types of lines used in building plans.
• Interpret basic architectural symbols for doors, windows, etc.
• Understand the purpose and importance of detailing.
• Identify common drawing scales and perform simple conversions.

Lesson summary

This week, we begin our exploration of working drawings, detailing, and the interpretation of building plans. This is a fundamental skill for any Civil Technology student and is directly relevant to the South African built environment. From the construction of RDP houses to multi-million rand commercial developments, accurate and understandable building plans are essential. Imagine a builder trying to erect a structure without clear instructions – the result would be chaotic and potentially dangerous! Understanding building plans allows you to participate effectively in the construction process, whether you're designing, supervising, or building.

Lesson notes

What are Working Drawings? Working drawings are a comprehensive set of technical drawings that provide all the information needed to construct a building or structure. They are the primary communication tool between architects/engineers and builders. They're not just pretty pictures; they're precise instructions.

They include: Architectural Drawings: These show the overall design and appearance of the building, including floor plans, elevations, sections, and details.

Structural Drawings: These show the structural elements of the building, such as foundations, beams, columns, and slabs. They ensure the building is safe and stable.

Services Drawings: These show the electrical, plumbing, and mechanical systems of the building.

Types of Architectural Drawings: Floor Plans: These are horizontal sections cut through the building, typically about 1 meter above the floor level. They show the arrangement of rooms, walls, doors, windows, and other features on each floor. Think of it as a bird's-eye view if you cut the building.

Elevations: These are orthographic projections showing the exterior views of the building from different sides (front, rear, left, right). They show the height and appearance of the building. Imagine standing directly in front of the building; that's what an elevation shows.

Sections: These are vertical cuts through the building, showing the internal construction and relationships between different levels. They're useful for understanding the structure and materials used. It's like slicing a cake open to see the layers.

Detail Drawings: These are large-scale drawings of specific building components or features, such as window details, wall sections, or joint details. They provide precise information for construction. They zoom in on small parts to show how they're built.

Lines in Building Plans: Different types of lines are used to represent different features in building plans. Understanding these lines is crucial for accurate interpretation.

Visible Lines (Continuous Thick): These represent the outlines of visible objects and features. They are the most prominent lines on the drawing.

Hidden Lines (Dashed Thin): These represent edges and features that are hidden from view. They are less prominent than visible lines.

Center Lines (Long-Short Dashed): These indicate the center of symmetrical objects or features. Dimension Lines (Continuous Thin with Arrows): These show the dimensions of objects and features. The dimension figure is placed above the line.

Extension Lines (Continuous Thin): These extend from the object to the dimension line. Cutting Plane Lines (Long-Short-Short Dashed, Thick Ends): These indicate the location of a section cut. The arrows at the ends show the viewing direction.

Architectural Symbols: Building plans use a variety of symbols to represent common building components.

Some examples include: Doors: Typically represented by an arc indicating the direction of swing.

Windows: Represented by two or three parallel lines within the wall.

Toilets/Sanitary Fixtures: Represented by simplified shapes of the fixtures (e.g., a circle for a toilet).

Stairs: Represented by a series of parallel lines with an arrow indicating the direction of ascent.

Detailing: Detailing is the process of creating detailed drawings of specific building components. These drawings provide precise information on materials, dimensions, and construction methods. Good detailing is essential for accurate construction and avoids ambiguity on site. For example, a detail drawing of a window sill might show the exact dimensions of the sill, the type of material used, and how it is attached to the wall.

Drawing Scales: Building plans are drawn to scale, which means that the dimensions on the drawing are proportional to the actual dimensions of the building.

Common scales include: 1:50: 1 unit on the drawing represents 50 units in reality (e.g., 1 cm on the drawing = 50 cm in reality). Used for detailed plans and sections. 1:100: 1 unit on the drawing represents 100 units in reality. Used for floor plans and elevations. 1:200: 1 unit on the drawing represents 200 units in reality. Used for site plans and smaller buildings.

Example Calculation: Scale Conversion Let's say a wall measures 5 meters in reality and the plan is drawn to a scale of 1:

5

0. What is the length of the wall on the drawing?

Convert meters to centimeters: 5 meters = 500 cm Apply the scale: 500 cm / 50 = 10 cm Therefore, the wall will be 10 cm long on the drawing.