Lesson Notes By Weeks and Term v5 - Grade 11
Working drawings, detailing and interpretation of building plans – Week 10 focus
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Working drawings, detailing and interpretation of building plans – Week 10 focus
Download the Lessonotes Mobile South Africa app for faster lesson access on Android and iPhone.
Subject: Civil Technology
Class: Grade 11
Term: Term 4
Week: 10
Theme: General lesson support
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Working drawings, detailing, and the interpretation of building plans are fundamental skills for any Civil Technology student and future professional. In South Africa, with our ever-growing need for infrastructure and housing, the ability to understand and utilize building plans is essential. From participating in community upliftment projects involving construction to simply understanding the blueprint of your own home, these skills provide crucial insights into the built environment around us. Imagine being able to identify potential structural issues in a building or accurately estimate the materials needed for a renovation project. That's the power of understanding building plans!
2. 1. Standard Symbols and Conventions (SANS 10400): Building plans adhere to specific standards, and in South Africa, SANS 10400 (The application of the National Building Regulations) is crucial. These standards dictate symbols, line types, abbreviations, and other conventions to ensure clarity and avoid misinterpretation.
Line Types: Thick Continuous Line: Used for visible outlines of walls, columns, and other primary structural elements.
Thin Continuous Line: Used for dimensions, hatching, leaders, and hidden details when necessary.
Dashed Line: Represents hidden features or elements below the surface. Chain Line (Long dash, short dash): Represents center lines.
Symbols: These are standardized representations of building elements.
Some common examples include: Door Symbol: Usually a quarter circle indicating the swing direction.
Window Symbol: Two or three parallel lines indicating the window pane.
Stair Symbol: A series of parallel lines with an arrow indicating the direction of ascent.
Plumbing Fixture Symbols: Standard symbols exist for toilets, sinks, baths, etc. (Refer to SANS 10400).
Electrical Symbols: Represent electrical outlets, switches, lighting fixtures, etc. (Refer to SANS 10400).
Material Hatching: Different hatching patterns represent different materials (e.g., concrete, brick, steel).
Abbreviations: Shortened forms of words used for efficiency (e.g., "WC" for Water Closet, "FL" for Floor Level, "RC" for Reinforced Concrete). 2.
2. Reading and Interpreting Foundation Details: Foundation details show the construction of the building's base.
They typically include: Foundation Type: Strip footing, raft foundation, pile foundation (rare for typical residential).
Dimensions: Width, depth, and thickness of the foundation.
Reinforcement: Size, spacing, and type of steel reinforcement (if applicable).
Materials: Concrete mix ratio (e.g., 25 MPa), type of aggregate.
Damp-Proof Course (DPC): A layer of waterproof material to prevent rising damp.
Example: A foundation detail might specify a "600mm wide x 450mm deep strip footing, reinforced with 4 Y12 bars bottom and 2 Y12 bars top, using 25MPa concrete, and a DPC layer 150mm above ground level." This means the footing is 600mm wide and 450mm deep, contains four 12mm diameter steel reinforcing bars at the bottom and two at the top, is made with 25MPa concrete, and has a damp-proof course 150mm above the surrounding ground level. 2.
3. Reading and Interpreting Wall Details: Wall details illustrate the construction of the walls, including: Wall Type: Brick wall, block wall, timber frame wall, etc.
Thickness: The width of the wall (e.g., a "230mm brick wall" refers to the thickness).
Materials: Type of brick or block, mortar mix ratio, plaster type.
Wall Finishes: Plaster, paint, cladding.
Lintels: Beams above openings (doors, windows) that support the wall above. The material (concrete, steel) and dimensions will be specified.
Damp-Proof Course (DPC): Usually at the base of the wall to prevent rising damp.
Example: A wall detail might specify a "230mm brick wall with a 1:6 cement:sand mortar mix, plastered internally and externally, with a concrete lintel above window openings." This means the wall is made of brick and is 230mm thick, the mortar used to bind the bricks is a mix of one part cement to six parts sand, the wall is covered with plaster on both sides, and concrete lintels are used above windows to support the wall above the opening. 2.
4. Reading and Interpreting Roof Details: Roof details depict the construction of the roof, including: Roof Type: Gable roof, hip roof, flat roof, etc.
Roof Covering: Tiles, corrugated iron, thatch.
Roof Structure: Rafters, purlins, trusses.
Insulation: Type and thickness of insulation material.
Ventilation: Provision for air circulation to prevent condensation.
Overhang: The distance the roof extends beyond the walls.
Example: A roof detail might specify a "Gable roof with corrugated iron sheeting, supported by timber rafters at 600mm centers, with 50mm thick insulation, and a 450mm overhang." This means the roof is a gable roof (two sloping sides meeting at a ridge), the roof covering is made of corrugated iron sheets, the timber rafters that support the roof are spaced 600mm apart, there is 50mm thick insulation material, and the roof extends 450mm beyond the walls. 2.
5. Construction Details: Construction details are enlarged drawings showing how different building elements are connected or constructed. These are essential for clarity and precision.
They might include details for: Wall-to-foundation connection Window or door jamb detail Eaves detail (where the roof meets the wall) Staircase detail 2.
6. Calculating Quantities: Building plans contain dimensions that allow for basic quantity calculations. For example, you can calculate: Wall Length: By measuring the distance between two points on the plan.
A rectangular room is 4m long and 3m wide. The walls are 2.8m high. Calculate the total area of the walls.
Perimeter of the room: 2 (4m + 3m) = 14m
Total wall area: 14m 2.8m = 39.2 square meters
Guided Practice (With Solutions)
Question 1: Identify the material represented by the following hatching pattern: [Insert a simple hatching pattern for brick].
Solution: The hatching pattern represents brick. [Explanation: Common knowledge, cross-reference against a material hatching chart.]