Last reviewed 16 Sept 2026 · 8 min read
Purpose of building drawings
Building drawings communicate the design of a building to the owner, approving authorities, estimators and builders. They form the basis for approval, estimation, tendering, construction and maintenance.
Relevant standard: IS 962 — Code of practice for architectural and building drawings (with SP 46 for general drawing practice).
Types of building drawings
| Drawing | Content | Typical scale |
|---|---|---|
| Key plan | Location of the site relative to surrounding landmarks, roads and towns | Small (e.g. 1 : 10 000 or not to scale) |
| Location plan | Position of the plot with surrounding roads and features | 1 : 1000 to 1 : 2500 |
| Site plan | Plot boundaries, building position, setbacks, access, north line, drainage, services, trees | 1 : 200 to 1 : 500 |
| Line diagram | Single-line sketch showing arrangement and sizes of rooms (not to exact scale) | — |
| Plan | Horizontal section through the building at about window sill/lintel level (commonly about 1 m above floor) seen from above — walls, openings, rooms, stairs, fixtures | 1 : 100 (or 1 : 50) |
| Elevation | External view of a face of the building — front, rear, side elevations | 1 : 100 |
| Section | Vertical cut through the building showing foundations, floor levels, heights, roof, stairs, openings | 1 : 100 or 1 : 50 |
| Working drawings | Detailed drawings used for construction with full dimensions and specifications | Various |
| Detail drawings | Enlarged details — doors, windows, stairs, joinery, RCC reinforcement, connections | 1 : 20, 1 : 10, 1 : 5 |
| Submission drawings | Drawings submitted to local authority for building permission — site plan, plans, elevation, section, area statement, as per bye-laws | As required |
| Structural drawings | Foundation plans, column layouts, beam and slab reinforcement details | Various |
| Services drawings | Water supply, drainage, electrical, HVAC layouts | 1 : 100 |
| As-built drawings | Record of the building as actually constructed | — |
Conventions for building drawings
- Orientation — plan drawn with north preferably towards the top of the sheet; north line shown.
- Views arrangement — plan at the bottom, elevation above it (projected), section to the side (first-angle arrangement), or as convenient on separate sheets.
- Section line — marked on plan (e.g. A–A) and chosen to pass through staircase, doors and windows, WC/bath, and other important features to show maximum information.
- Wall thickness drawn to scale; cut walls in plan shown by thick lines or hatched; openings shown with door swings and window symbols.
- Dimensions — overall and room dimensions; levels (plinth, floor, lintel, roof) in sections and elevations; units stated.
- Material symbols and conventional signs (see Conventional Signs & Symbols).
- Room names, schedule of doors and windows (e.g. D1, W1, V1 with sizes), specifications notes, title block.
Principles of planning
| Principle | Meaning |
|---|---|
| Aspect | Arrangement of rooms to receive sunlight and breeze as desired (e.g. kitchen receiving morning sun, bedrooms suitably oriented) |
| Prospect | External view from rooms — pleasant views, avoiding undesirable views |
| Privacy | Privacy of rooms from outside and within the building (e.g. bedrooms and toilets not visible from entrance) |
| Grouping | Placing related rooms close — kitchen near dining, toilet near bedrooms |
| Roominess | Getting maximum benefit from minimum dimensions — proper proportions (length/width about 1.2–1.5) |
| Furniture requirements | Room sizes and door/window positions suited to furniture layout |
| Sanitation | Light, ventilation, cleanliness and sanitary provisions |
| Flexibility | Rooms usable for different purposes |
| Circulation | Movement within the building — horizontal (passages, corridors) and vertical (stairs, lifts); minimum and without disturbing privacy |
| Elegance | Pleasing appearance — elevation, proportions |
| Economy | Efficient use of space and materials |
| Orientation | Positioning of the building with respect to sun, wind and rain for comfort (in hot climates, longer walls commonly facing north–south) |
Typical dimensions (indicative)
| Element | Typical values |
|---|---|
| Plinth height | About 450–600 mm above ground |
| Floor to ceiling height (habitable rooms) | About 2.75–3.0 m (bye-laws specify minimums) |
| Door sizes | Main door about 1000 × 2100 mm; internal doors 900 × 2100 mm; toilet doors 750 × 2100 mm |
| Window sill height | About 750–900 mm above floor |
| Lintel level | About 2.1 m above floor |
| Ventilator | Near ceiling, e.g. 600 × 450 mm |
| Parapet height | About 900–1000 mm |
| Staircase | Rise about 150–190 mm; tread (going) about 250–300 mm; width about 900–1200 mm in residences; headroom at least about 2.1 m |
| Ventilation | Openings commonly at least about 1/10 of floor area (bye-laws/NBC) |
Minimum room sizes, heights, ventilation, setbacks, floor area ratio (FAR/FSI) and ground coverage are governed by the local building bye-laws (many states adopt the Model Building Bye-Laws framework). Always use the bye-laws applicable to the site.
Drawing plan, section and elevation from a line diagram
- Study the line diagram — room sizes (usually internal dimensions), wall thickness, openings, specifications.
- Plan: draw centre lines/wall lines to scale; mark wall thicknesses; locate doors, windows, ventilators; show stairs, verandah, steps, sunshades (dashed), kitchen platform, sanitary fittings; dimensions; room names; section line and north line.
- Section: project widths from the plan; draw ground line, foundation (trench, PCC bed, footings), plinth, DPC, floor, walls cut, openings (door/window in section), lintel, sunshade, roof slab, parapet; show levels and heights; hatch cut portions with material symbols.
- Elevation: project widths from the plan and heights from the section; show plinth, doors, windows, sunshades, roof, parapet, steps, rainwater pipes; no hidden lines; add textures as needed.
- Add title block, schedule of openings, specifications and scale.
Staircase planning
FormulaStaircase rules of thumb
- 2R + T ≈ 550–700 mm (commonly about 600 mm)
- R × T ≈ 40 000–45 000 mm² (commonly quoted)
- Number of treads in a flight = number of risers − 1
- Going of flight = number of treads × tread
- Maximum risers per flight commonly limited (about 12–15); landings at least equal to stair width.
- Handrails at about 850–1000 mm height.
Worked examples
Worked ExampleExample 1 — staircase design
A dog-legged stair connects floors 3.0 m apart in a staircase room with internal width 2.2 m. Take rise 150 mm and tread 250 mm. Plan the stair.
Solution. Number of risers 20 → two flights of 10 risers each. Treads per flight 9; going 2250 mm per flight. Width of each flight ; with a 100 mm gap → 1050 mm each. Check: mm (acceptable; lower bound). Room length ≈ landing (1050 mm) + going (2250 mm) = 3300 mm internal length (plus any floor landing space).
Worked ExampleExample 2 — ventilation check
A bedroom of 3.6 m × 3.0 m has one window of 1.2 m × 1.2 m and a ventilator of 0.6 m × 0.45 m. Does it meet 1/10 of floor area as opening?
Solution. Floor area m² → required m² Openings m² → adequate
Worked ExampleExample 3 — plan cutting level
At what level is a building plan assumed to be cut, and why?
Solution. At about window sill/lintel level (roughly 1 m above floor) so that walls, doors and windows are all cut and shown; features above (sunshades, beams) are shown dashed.
Frequently tested points
- IS 962 — architectural and building drawings.
- Key plan (surroundings) → location plan → site plan (plot, setbacks, north) → plan, elevation, section → details.
- Plan = horizontal section at about sill/lintel level, 1 : 100; details 1 : 20/1 : 10.
- Section line passes through staircase, doors, windows and toilets.
- North line; schedule of doors and windows; levels in sections.
- Principles of planning: aspect, prospect, privacy, grouping, roominess, furniture, sanitation, flexibility, circulation, elegance, economy, orientation.
- Stair: 2R + T ≈ 550–700 mm; treads per flight = risers − 1; headroom ≥ about 2.1 m.
- Submission drawings follow local building bye-laws (FAR, setbacks, coverage).
Common MistakeCommon mistakes
- Drawing elevations with hidden lines or inconsistent heights from the section.
- Selecting a section line that misses the staircase and openings.
- Counting treads equal to risers in a flight.
Revision SummaryChapter summary
- Building drawings range from key, location and site plans to plans, elevations, sections, details, submission and as-built drawings.
- IS 962 conventions govern orientation, scales, section lines, dimensions, levels, symbols and schedules.
- Principles of planning — aspect, prospect, privacy, grouping, roominess, circulation and others — guide room arrangement.
- Plans, sections and elevations are developed from line diagrams by projection, using typical dimensions and bye-law requirements.
- Staircases are planned with rise–tread relations, flights, landings and headroom.