Lesson Notes By Weeks and Term v5 - Grade 10
Introduction to civil drawings and reading building plans – Week 2 focus
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Introduction to civil drawings and reading building plans – Week 2 focus
Download the Lessonotes Mobile South Africa app for faster lesson access on Android and iPhone.
Subject: Civil Technology
Class: Grade 10
Term: Term 4
Week: 2
Theme: General lesson support
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This week, we delve deeper into the fascinating world of civil drawings and building plans. Last week, we covered the basic tools, line types and symbols. This week we're going to look at more detailed drawing types and their conventions. Understanding these plans is crucial, not just for future civil technologists, but for anyone involved in building, renovating, or even understanding the structures around them. Think about the new housing developments springing up across South Africa, the upgrades to our infrastructure, or even the renovations you might do on your own home one day. All of these rely on accurate and interpretable civil drawings and building plans.
This week, we will cover four key areas: Different Types of Civil Drawings, Reading Scales, Architectural Symbols and Abbreviations, and Drawing Conventions. A. Different Types of Civil Drawings Civil drawings come in several forms, each serving a specific purpose in the design and construction process. Understanding these differences is fundamental.
Site Plan: This drawing provides an overhead view of the entire site, showing the location of the building(s) relative to property lines, existing structures, roads, utilities (water, sewer, electricity), landscaping, and other relevant features. It's like a map of the building's location. Think of a township development plan showing where each RDP house will be placed on the land, alongside the planned roads and water pipes.
Floor Plan: A floor plan is a horizontal section of the building, typically taken about 1.2 meters above the floor level. It shows the arrangement of rooms, walls, doors, windows, staircases, and other interior features. It is a bird’s eye view inside the building. This is the plan you'd consult to see the layout of a house or office building, including the position of the bathroom and kitchen.
Elevation: An elevation is a vertical view of the building's exterior from a specific side (front, rear, left, or right). It shows the height of the building, the roofline, the placement of windows and doors, and the external finishes (brick, plaster, cladding). It gives the overall aesthetic view of the building. Imagine looking at the completed building from the street - that's similar to what an elevation shows.
Section: A section is a vertical cut through the building, revealing the internal structure and construction details. It shows the layers of the walls, the floors, the roof, and how these elements are connected. Think of cutting a cake to see the layers of icing and sponge. Sections are crucial for understanding how the building is put together.
Details: These are enlarged drawings showing specific construction elements (e.g., a window jamb detail, a foundation detail) at a larger scale, providing more information about materials, dimensions, and connections. These are zoomed-in views of particular areas. B. Reading Scales A scale is the ratio between the size of the drawing and the actual size of the object it represents. It is essential to understand and use scales accurately.
Representative Fraction (RF): This is expressed as a ratio, such as 1:100 or 1:50. 1:100 means that 1 unit on the drawing represents 100 units in reality. For example, 1 cm on the drawing represents 100 cm (or 1 meter) in the real world.
Graphical Scale: This is a bar drawn on the plan, divided into segments representing specific distances on the ground. You can use a ruler to measure a distance on the drawing and then compare it to the graphical scale to determine the actual distance.
Example: A floor plan has a scale of 1:
5
0. A wall measures 5 cm on the drawing. What is the actual length of the wall?
Solution: 1 cm on the drawing = 50 cm in reality.
Therefore, 5 cm on the drawing = 5 cm 50 = 250 cm = 2.5 meters. The actual length of the wall is 2.5 meters. Why different scales? A site plan of a large property might use a scale of 1:1000 or even 1:2000, while a detailed section of a wall might use a scale of 1:10 or 1:5 to show all the necessary details clearly. C. Architectural Symbols and Abbreviations Building plans use a standardized set of symbols and abbreviations to represent different features. Being familiar with these is key to accurate interpretation.
Some common ones include: Doors: Doors are typically represented by an arc indicating the swing direction and a straight line indicating the door leaf.
Windows: Windows are usually shown as two or three parallel lines within the wall thickness.
Walls: Walls are represented by thick lines, with different line types indicating different materials (e.g., solid lines for brick walls, dashed lines for partition walls).
Abbreviations: Common abbreviations include: W.C. (Water Closet - toilet) K (Kitchen) BR (Bedroom) LV (Living Room) D (Door) W (Window) FL (Floor Level)
Example: Imagine seeing a symbol on the plan consisting of two parallel lines within a wall, and adjacent to it is the abbreviation "W". This indicates that there is a window at that location. D. Drawing Conventions Drawing conventions are the established rules and standards for creating and interpreting civil drawings. Adhering to these ensures clarity and consistency.
Line Weights: Different line weights are used to differentiate between important features and less important details. Thicker lines are generally used for walls and structural elements, while thinner lines are used for dimensions and annotations.
Dimensioning: Dimensions are used to indicate the size and location of features. They are typically shown using extension lines, dimension lines, and arrowheads, with the dimension value written above or below the dimension line.