Lesson Notes By Weeks and Term v5 - Grade 11

Lesson Video

This page supports the lesson note with a companion video and a short classroom-ready summary.

For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.

Performance objectives

• Draw a simple foundation plan.
• Construct an elevation drawing from the plan.
• Identify key structural elements like footings and DPC.
• Apply correct line types as per SANS 10111.
• Use appropriate annotations and dimensions.

Lesson summary

This week, we delve into the essential realm of civil drawing, focusing specifically on foundational plans and elevations. This knowledge is not just about drawing lines on paper; it's about understanding the language of construction, the blueprint for building our homes, schools, hospitals, and the very infrastructure that sustains our communities. In a country like South Africa, where infrastructure development is crucial for economic growth and social upliftment, understanding these drawings is fundamental.

Lesson notes

2.1 Foundation Plans: A foundation plan is a scaled, orthographic projection (top view) drawing that shows the layout and dimensions of the building's foundation. It's essentially a "map" of the underground structural elements that support the building. Understanding this plan is crucial because the foundation bears the entire weight of the structure.

Key Elements Shown in a Foundation Plan: Footings: These are the widened bases of foundation walls and columns that distribute the building's weight over a larger area of soil. They prevent the building from sinking or settling unevenly. Footings are usually shown as hidden detail in the plan view above the ground.

Foundation Walls: These walls extend from the footing to the ground level and provide lateral support for the building. They are typically made of concrete or masonry.

Columns: If the building design includes columns for support, their location and size are indicated on the foundation plan.

Damp-Proof Course (DPC): This is a waterproof barrier placed within the foundation wall to prevent moisture from rising up into the building's walls (capillary action). On a plan, it may not always be explicitly visible but the location of the level would be marked.

Slab: Some buildings may have a concrete slab on grade (directly on the ground). The thickness and reinforcement details of the slab are often shown on the foundation plan.

Dimensioning: Accurate dimensions are critical on a foundation plan. Dimensions specify the size and location of all foundation elements.

Centerlines: Centerlines are used to accurately locate walls, columns, and other elements.

Hatching/Symbols: Specific hatching patterns or symbols are used to represent different materials, such as concrete, brick, or earth. Refer to SANS 10111. 2.2 Elevations: An elevation drawing is a scaled, orthographic projection (front, side, or rear view) of the building. It shows the vertical relationships between different parts of the building and how the foundation interacts with the above-ground structure. Think of it as a view of the building as if you were standing directly in front of it.

Key Elements Shown in an Elevation: Ground Level (GL): This is the reference point for all vertical measurements. It's usually indicated by a thick line with a label.

Top of Foundation Wall: This indicates the height of the foundation wall above the ground level.

Top of Footing: This shows the depth of the footing below the ground level.

Finished Floor Level (FFL): This is the level of the finished floor inside the building.

Damp-Proof Course (DPC): Clearly indicated as a horizontal line above the ground level, demonstrating its position protecting the walls.

Building Height: Overall height of the structure Wall Finishes: Indication of brickwork, plaster etc. 2.3 Line Types and Conventions: Adhering to standard drawing conventions is crucial for clear communication. According to SANS 10111, you should use: Visible lines: Thick, continuous lines for outlining visible edges and surfaces.

Hidden lines: Dashed lines to show features that are behind other surfaces.

Centerlines: Long-dashed dotted lines to indicate the center of symmetrical features.

Dimension lines: Thin, continuous lines with arrowheads at each end, indicating the distance being measured.

Extension lines: Thin, continuous lines extending from the object to the dimension lines.

Cutting plane lines: Thick dashed lines that indicate where a section has been cut. 2.4 Scale: Scale is the ratio between the size of the drawing and the actual size of the object. Common scales for foundation plans and elevations include 1:50, 1:100, and 1:

2

0

0. A scale of 1:100 means that 1 unit on the drawing represents 100 units in reality (e.g., 1 cm on the drawing represents 100 cm or 1 meter in reality).

Example 1: Simple Foundation Plan and Elevation for a Small Shed Let's say we're designing a small storage shed with the following specifications: Outer dimensions: 3m x 4m Foundation walls: 200mm thick concrete Footings: 600mm wide, 300mm deep DPC: 150mm above ground level Foundation Plan: Draw the outer rectangle: Using a scale of 1:50, draw a rectangle representing the outer dimensions of the shed (60mm x 80mm on your drawing).

Draw the foundation walls: Offset the outer rectangle inwards by 200mm (4mm on your drawing) to represent the foundation walls.

Draw the footings (Hidden Detail): Offset the outer rectangle outwards by 200mm on each side to represent hidden detail of the footings(footing is 600mm, wall is 200mm, so 600-200=400 difference. Divide by 2, 200mm each side of wall). Use hidden lines to indicate they are below ground.

Add Centerlines: Draw centerlines running through the center of the walls.

Dimensioning: Add dimensions indicating the overall size of the shed, the width of the foundation walls, and the width of the footings.

Elevation: Draw the Ground Level: Draw a thick horizontal line to represent the ground level (GL).