Building Planning and Drawing
This domain tests the principles of residential planning, the standard minimum dimensions, the meaning of floor area ratio and setbacks, and the conventions of a building drawing - scale, line types and symbols.
Principles of planning
- Orientation places the building to catch good sun and breeze; aspect is the direction a room faces (kitchen east, bedroom south-west is a common rule).
- Prospect is the view seen from a window; privacy, circulation, roominess, flexibility and economy complete the list.
- Rooms are grouped to keep the kitchen near the dining, bedrooms away from the entrance, and toilets on a common service wall.
Standards and controls
- Typical minimum sizes used in Indian practice: bedroom about 3.0 × 3.6 m, kitchen width at least 1.8 m, bathroom about 1.2 × 2.1 m, door 0.9 × 2.1 m, lintel level 2.1 m.
- Floor area ratio = total floor area of all floors ÷ plot area. Setbacks are the minimum open distances from the plot boundary fixed by the local development rules.
Drawing conventions
- Scale 1:100 means 1 cm on the sheet = 1 m on the ground; a site plan is usually 1:500, detailed drawings 1:50 or 1:20.
- Thick continuous lines for visible outlines, dashed lines for hidden work, chain-dotted lines for centre lines; north arrow on every plan.
Worked example
A 300 m² plot has a permissible FAR of 1.5, so the maximum buildable area is 300 × 1.5 = 450 m². If the plan proposes 540 m², it exceeds the limit by 90 m² and must lose one floor or reduce room sizes. With a 60% ground coverage limit, the ground floor cannot exceed 180 m², so 450 m² needs about 2.5 floors.
Marks-losing traps
- Swapping aspect (direction faced) with prospect (view).
- Confusing plinth area (measured to outside walls) with carpet area (usable floor inside).
- Reading a 1:50 drawing as if 1 cm were 1 m.