Lesson Notes By Weeks and Term v5 - Grade 11

Lesson Video

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Performance objectives

• Identify symbols and abbreviations from SANS 10400.
• Interpret detailed sections and elevations.
• Explain the relationship between different drawing types.
• Understand reinforcement detailing in concrete.
• Apply SANS 10400 principles to building plans.

Lesson summary

Working drawings are the backbone of any construction project. They provide precise instructions for builders, engineers, and other stakeholders, ensuring that the final structure matches the architect's vision and complies with all relevant regulations. In South Africa, understanding working drawings is particularly crucial. With the rapid growth of urban areas and ongoing housing initiatives, skilled individuals who can accurately interpret and utilize these plans are in high demand. This week, we'll delve deeper into the intricacies of working drawings, focusing on detailing and interpretation, equipping you with essential skills for your future careers.

Lesson notes

2. 1. Understanding Working Drawings Working drawings, also known as construction drawings, are a set of detailed drawings used by contractors and builders to construct a building. They are more detailed than preliminary or architectural drawings and provide specific instructions for the construction process. These plans form a legal document between the client and the builder. In South Africa, these drawings must adhere to SANS 10400 (The application of the National Building Regulations).

Types of Working Drawings: Site Plan: Shows the location of the building on the property, including boundaries, setbacks, easements, existing structures, and utilities. It's crucial for understanding the context of the building. In South Africa, site plans must consider local bylaws regarding building lines and erf coverage.

Floor Plans: A horizontal section cut through the building at a specific height (typically window height), showing the arrangement of rooms, walls, doors, windows, and other features.

Elevations: Orthographic projections showing the exterior views of the building from different sides (front, rear, left, and right). Elevations show the vertical relationships of building elements, like roof pitch, window heights, and overall building height.

Sections: Vertical cuts through the building, revealing the internal construction details of walls, floors, roofs, and foundations. Sections are vital for understanding the layering of materials and the structural integrity of the building.

Details: Enlarged drawings of specific building components, such as wall junctions, window sills, roof eaves, and staircases. Details provide precise information about materials, dimensions, and construction methods.

Structural Drawings: Show the structural elements of the building, including foundations, columns, beams, and slabs. These drawings are prepared by structural engineers and specify the size, type, and location of reinforcing steel (rebar).

Services Drawings: Show the layout of plumbing, electrical, HVAC (heating, ventilation, and air conditioning), and other building services. 2.

2. Symbols and Abbreviations (SANS 10400) Understanding symbols and abbreviations is fundamental to interpreting working drawings. SANS 10400 provides standardized symbols and abbreviations for use in building plans in South Africa.

Examples: WC: Water Closet (toilet)

WHB: Wash Hand Basin (sink) DB: Distribution Board (electrical panel) GL: Ground Level FGL: Finished Ground Level RC: Reinforced Concrete Reo: Reinforcement Steel (rebar) ⌀ (or dia): Diameter (used for pipes, rebar, etc.) CL: Center Line DPC: Damp Proof Course SANS 10400: South African National Standard 10400 Wall Symbols: Wall symbols vary depending on the wall type (brick, concrete block, stud wall). A brick wall is typically represented by parallel lines with hatch marks in between. Concrete block walls may have a different hatching pattern. Stud walls are often represented by a single line with short diagonal lines indicating the studs.

Door and Window Symbols: Doors are represented by an arc showing the direction of swing. Windows are represented by lines indicating the window frame and glazing.

Reinforcement Steel Symbols: Reinforcement steel is represented by solid or dashed lines with notations indicating the bar size, spacing, and location. 2.

3. Detailing of Building Components Detailing is the process of creating enlarged drawings of specific building components to show how they are constructed. These details provide precise information about materials, dimensions, and construction methods.

Examples: Foundation Detail: Shows the dimensions and construction of the foundation, including the footing, foundation wall, and damp-proof course. It specifies the type of concrete, the size and spacing of reinforcing steel (if required), and the depth of the footing. A typical South African foundation detail for a single-story house would show a strip footing of reinforced concrete, a brick wall above the footing, and a damp-proof course to prevent rising damp.

Wall Detail: Shows the construction of the wall, including the materials used (brick, block, plaster), the thickness of the wall, and any insulation or cladding. Different types of brick bonds (e.g., stretcher bond, English bond) will be indicated.

Roof Detail: Shows the construction of the roof, including the rafters, purlins, battens, and roofing material (tiles, corrugated iron). It specifies the roof pitch, the type of insulation, and any flashing or waterproofing. In coastal regions of South Africa, roof details need to address issues of corrosion due to salt spray.

Window Detail: Shows the construction of the window frame, glazing, and sill. It specifies the type of window (sliding, casement, awning), the size of the glazing, and any weatherstripping.

Door Detail: Shows the construction of the door frame, door leaf, and hardware.

Worked example

Consider a reinforced concrete beam shown on a structural drawing. The drawing indicates "3Y20" at the bottom (tension side) and "2Y16" at the top (compression side). Stirrups are indicated as "R10 @ 150 c/c".

Interpretation: This means the beam has three 20mm diameter high-yield steel bars at the bottom, two 16mm diameter high-yield steel bars at the top, and 10mm mild steel stirrups spaced at 150mm centers.

Application: This information is crucial for the steel fixer who will fabricate and install the rebar cage for the beam. The engineer needs to verify the design based on SANS standards.

Guided Practice (With Solutions)

Question 1: Identify the meaning of the following abbreviations commonly found on South African building plans:

a) FFL

b) RWP

c) MH

d) THK

Solution: