Part 1 of 3
Doors, Windows & Ventilators
Last reviewed 16 Sept 2026 · 10 min read
Doors
A door is a movable barrier that provides access into and within a building, while controlling privacy, security, light, air and sound.
Location of doors
- Placed to give convenient circulation without wasting room area — preferably near room corners (about 200 mm or more from the corner to allow the shutter to fold against a wall).
- Doors of opposite rooms or of a room on a corridor are aligned for ventilation where desirable.
- Number of doors in a room kept to a minimum (more doors reduce usable wall space and privacy).
- Direction of opening suited to use (usually opening into rooms; outward for public exits and toilets in some situations for safety).
Size of doors
Door sizes depend on use, traffic and furniture movement. Typical sizes in residential buildings: external/main doors about 1.0 × 2.1 m; internal doors about 0.9 × 2.0–2.1 m; bathroom/WC doors about 0.75 × 2.0 m; wider doors (double leaf) for public buildings, garages, hospitals (stretchers/wheelchairs).
A rule of thumb sometimes used for proportion: width ≈ 0.4 to 0.6 × height, and height ≈ width + 1.2 m. For accessibility, a clear door width of about 900 mm or more is recommended.
Parts of a door
Door frame:
| Part | Description |
|---|---|
| Head | Top horizontal member of the frame |
| Jambs (posts) | Vertical side members |
| Sill / threshold | Bottom horizontal member (often omitted in internal doors) |
| Horns | Extensions of the head beyond the jambs, built into masonry for anchorage |
| Rebate | Recess cut in the frame to receive the shutter |
| Holdfasts | Mild steel flats fixed to the frame and embedded in masonry (commonly three on each side for door frames) |
Door shutter:
| Part | Description |
|---|---|
| Stiles | Vertical outside members — hanging stile (carries hinges) and shutting (lock) stile |
| Rails | Horizontal members — top rail, lock (middle) rail, bottom rail, frieze rail |
| Muntins | Intermediate vertical members between rails |
| Panels | Areas enclosed by stiles and rails (timber, plywood, glass, louvers) |
| Mullion | Vertical member dividing a frame into lights (in windows and wide frames) |
Types of doors
| Door | Construction / features | Use |
|---|---|---|
| Battened and ledged | Vertical boards (battens) nailed to horizontal ledges | Cheap — sheds, stores, toilets; tends to sag |
| Battened, ledged and braced | Diagonal braces added between ledges; braces slope upwards away from the hinged side so they act in compression and prevent sagging | Wider openings in sheds, stores |
| Battened, ledged, braced and framed | Battens and braces set within a frame of stiles and rails | Stronger, better appearance |
| Framed and panelled | Frame of stiles and rails with panels (timber, plywood, glass) held in grooves; panels may be raised or flat | Residential and public buildings — traditional |
| Glazed (sash) doors | Panels fully or partly glazed | Admit light — offices, verandahs, shops |
| Flush doors | Core (solid — blockboard/particle board; or hollow — frame with cellular core) faced with plywood/veneer on both sides; plain surfaces | Modern buildings — economical, easy to clean, available in standard sizes |
| Louvered (venetian) doors | Louvers (slats inclined downward outward) in frame — ventilation with privacy | Toilets, bathrooms, cupboards |
| Wire gauzed (fly-proof) doors | Wire mesh panels | Kitchens, dining areas, hospitals — keep out insects |
| Swing doors | Shutters hung with double-action spring hinges so they open both ways and return | Offices, hospitals, public buildings |
| Sliding doors | Shutters slide on tracks/rollers | Garages, godowns, shops, where swing space is limited, wardrobes |
| Revolving doors | Leaves rotate about a central vertical axis in a circular enclosure | Public buildings with heavy traffic, air-conditioned buildings (reduce air loss) |
| Folding doors | Hinged leaves fold together | Wide openings — halls, shops, partitions |
| Collapsible steel doors | Steel channels and flats in a lattice that folds sideways | Shops, godowns, security grilles at entrances |
| Rolling shutters | Steel slats rolled up on a drum above the opening (manual or motorised) | Shops, garages, warehouses — security |
| Metal doors | Pressed steel or aluminium frames and shutters | Industrial buildings, fire exits, external doors |
| uPVC, PVC and FRP doors | Water resistant, termite proof | Bathrooms, toilets, humid areas |
| Fire doors | Fire-rated construction with self-closing devices and seals | Fire escape routes, shafts, compartments |
Windows
A window is an opening in a wall with a frame and shutters (sashes) to provide light, ventilation and view.
Location and size
- Placed to give good light and cross-ventilation, considering orientation, prevailing winds and privacy.
- Glazed area of windows is commonly at least about one-tenth of the floor area of habitable rooms (larger in hot humid climates; bye-laws vary).
- Sill height above floor is commonly about 750–900 mm in living rooms (lower where views are desired; higher in toilets and kitchens above counters).
- Window heads often kept at the same level as door heads (lintel level) for uniform appearance.
Parts of a window
Frame — head, sill (weathered and throated), jambs, mullions (vertical dividers) and transoms (horizontal dividers). Shutter/sash — stiles, top and bottom rails, glazing bars (sash bars) dividing glass panes, panels.
Types of windows
| Window | Features |
|---|---|
| Casement windows | Side-hung shutters opening like doors — most common in India |
| Double-hung (sash) windows | Two sashes sliding vertically in grooves, balanced by counterweights or springs — ventilation at top and bottom |
| Pivoted windows | Sash pivots about a horizontal or vertical axis — easy cleaning, ventilation control; common in industrial buildings |
| Sliding windows | Sashes slide horizontally on tracks — aluminium and uPVC windows; no projection |
| Louvered windows | Fixed or adjustable inclined slats (timber, glass) — ventilation with privacy, rain protection |
| Bay window | Projects outward from the wall (on corbels, cantilevers) — increases area, light and view |
| Dormer window | Vertical window in a sloping roof, with its own small roof — lights attic rooms |
| Corner window | Placed at the corner of a room — light and view in two directions; lintel/corner support needed |
| Gable window | In the gable end wall of a pitched roof |
| Clerestory window | High-level windows in a wall rising above an adjoining lower roof — light and ventilation to the interior of large halls |
| Skylight | Glazed window on a sloping roof, parallel to the roof slope |
| Lantern (roof light) | Glazed structure projecting above a flat roof with vertical or inclined glazed sides — light to deep interiors, stairwells |
| Fanlight | Small window above a door (often pivoted or fixed) |
| Fixed windows | Non-opening glazed panels — light and view only |
| French windows | Full-height casement windows opening like doors onto balconies or terraces |
| Steel, aluminium and uPVC windows | Factory-made sections — durable, weather-tight; aluminium and uPVC are common for sliding and casement windows |
| Jalousie / glass louvre windows | Adjustable glass slats |