Building Planning and Drawing
Scope of the domain
Building planning and drawing deals with orientation, ventilation, lighting, setbacks, floor area ratio and the drawings that communicate a building design. The exam tests planning principles, National Building Code-type norms, scales and plan, elevation and section.
Core rules and concepts
- Principles: orientation, cross-ventilation, daylight, privacy, circulation, sanitation, economy, flexibility and safety.
- Setback is the open space between the building line and the plot boundary; it provides light, air and fire access.
- Floor Area Ratio (FAR) = total floor area of all floors / plot area. Ground coverage = footprint area / plot area.
- A plan is a horizontal cut view; an elevation shows the external face; a section shows a vertical cut. Scale is the ratio of drawing length to actual length.
- Standard line types: continuous thick for visible edges, dashed for hidden edges, chain line for centre lines.
Worked example
A plot is 300 m². FAR = 1.5 and ground coverage = 60%. Maximum total floor area = 1.5 × 300 = 450 m². Maximum footprint = 0.60 × 300 = 180 m². If every floor is 180 m², 450/180 = 2.5 floors; therefore two full floors (360 m²) plus a partial third floor of 90 m² are permissible, but three full floors (540 m²) are not. Reasoning: FAR limits the sum of all floor areas, not just the ground floor.
Traps
Do not apply FAR only to the ground floor. Do not confuse FAR with ground coverage. Do not read a section as a plan. Convert drawing scales consistently; for example, 1:100 means 1 cm on paper = 100 cm = 1 m on site.