Doors and windows

A window is an opening in a wall, fitted with a frame and shutters, which admits light and air, gives a view and allows ventilation. Its sill is generally kept 0.75-0.9 m above the floor and the total window area is 10-20% of the floor area of the room.

Types of windows

 Casement        Sliding         Pivoted        Louvered
 +----+----+    +----+----+    +---------+    +---------+
 | /  | \  |    |    |>>> |    |    o    |    |=========|
 |/   |  \ |    |    |    |    |   /|\   |    |=========|
 +----+----+    +----+----+    +---------+    +---------+

A door shutter is the movable leaf that closes the opening. Based on construction of the shutter, doors are:

 Battened      Ledged&braced    Panelled        Flush          Louvered
 |||||||||     |=======|        +--+----+--+    +--------+    +--------+
 |||||||||     |=\====|         |  | P  |  |    |        |    |========|
 |||||||||     |==\===|         |  +----+  |    |        |    |========|
 ledges at     |===\==|         |  | P  |  |    +--------+    +--------+
 top, mid,     brace            +--+----+--+
 bottom

• Battened door: boards 100-150 mm wide and 20-40 mm thick joined by 3 ledges 100-150 mm wide.
• Panelled door: styles 100 x 40 mm, rails 100-200 x 40 mm, panels 15-20 mm thick.
• Flush door: plywood faces 3-6 mm thick glued on a frame with solid or hollow core.

Doors are classified by the way they work (open or move):

 Hinged         Sliding         Revolving       Rolling shutter
 +---+--+       +--+--+         +---o---+       ======= (drum)
 |  /   |       |  |>>|         |   |   |       |||||||
 | /    |       +--+--+         |---+---|       |||||||
 +---+--+       rails           +---o---+       |||||||

The general parts of doors and windows are shown below.

 DOOR                              WINDOW
 +----------------------+          +------------------+
 | head                 |          |     head         |
 | +------------------+ |          | +------+-------+ |
 | |   top rail       | |          | |      |       | |
 | |------------------| |          | | sash | sash  | |
 | |      panel       | |          | |      |       | |
 | |s  lock rail    s | |    jamb->| +------+-------+ |
 | |t  panel        t | |          |      sill        |
 | |y                 y| |          +------------------+
 | |l  bottom rail  l | |
 | +------------------+ |
 | threshold            |
 +----------------------+

Description of components

A battened (ledged) door is made of vertical boards (battens) held together by horizontal ledges. It is the simplest door shutter.

 FRONT ELEVATION               BACK ELEVATION
 +--+--+--+--+--+--+          +--------------+
 |  |  |  |  |  |  |          |==== ledge ===|  top ledge 150 x 30 mm
 |  |  |  |  |  |  |          |              |
 |  |  |  |  |  |  |          |==== ledge ===|  middle ledge
 |  |  |  |  |  |  |          |              |
 |  |  |  |  |  |  |          |==== ledge ===|  bottom ledge
 +--+--+--+--+--+--+          +--------------+
 battens (tongued & grooved)    (a brace is added in ledged & braced door)

Elements with usual sizes

The leaf thickness is 30-40 mm. Used for stores, sheds, outhouses, and low-cost houses.

Louvered door

A louvered door has shutter openings fitted with inclined slats (louvres) at about 45 degrees, fixed between the styles. The slats stop rain and direct view, yet allow air to pass. They are made of timber, steel or glass. The lower part may be panelled and the upper part louvered.

Uses: bathrooms, toilets, kitchens, store rooms, godowns and plant rooms where privacy and ventilation are both needed.

Revolving door

A revolving door has three or four leaves (wings) fixed to a central pivot that revolve within a circular enclosure (drum). People enter and leave by pushing the leaves round. At any time the leaves seal the opening, so very little air passes; thus heat loss from air-conditioned buildings is reduced and wind and dust are kept out.

   PLAN
    ___ ___
   /   |   \
  |----o----|   4 leaves on central pivot
   \___|___/

Uses: hotels, banks, airports, malls and offices with air conditioning. A normal swing door is provided beside it for emergency exit and for wheelchairs and goods.

A steel window uses rolled steel sections (Z, T or L, 20 x 20 x 3 mm), welded to form the frame and sashes. The sash may be fixed or openable (side-hung or top-hung).

 ELEVATION                       SECTION AT JAMB
 +------+-------+                  wall |  frame (Z 20x20x3)
 |      |       |                       | +--+
 |  F   |  O    |  F = fixed            | |  |= glass (3 mm)
 +------+-------+  O = openable         | +--+  putty
 |      |       |                       |  lug fixed in
 |  F   |  O    |                       |  wall 100 mm
 +------+-------+

Details: glass panes 3 mm are fixed in grooves with steel glazing clips and putty; frames are fixed to the wall by 100 mm long lugs (holdfasts) embedded in 1:3 mortar at 300 mm from top and bottom and not more than 450 mm between; handles and friction hinges for the openable sash; painted with red lead primer and enamel; typical size 1.2 m x 1.2 m.

A wooden door frame (chaukhat) can be fixed either while building the wall or after the wall is built.

1. Mark the position and centre line of the door on the plan and check the opening size.
2. Keep the frame vertical (plumb) and at correct level using a plumb bob and spirit level; support it with temporary props or diagonal braces so that it does not shift.
3. Place the horns (extensions of head and sill) in the wall; build the masonry around the frame.
4. Fix the frame to the wall by holdfasts (M.S. flats 25 x 6 mm, 300 mm long) screwed to the back of the jamb, three per jamb, one at 300 mm from the top and one at 300 mm from the bottom; embed the ends in the wall in 1:3 cement mortar or concrete blocks.
5. In the case of an RCC wall or column use rawl plugs/anchor bolts or bolts through the frame.
6. Check plumb and diagonals (equal diagonals mean a square frame), then coat the surfaces touching the wall with coal tar or bitumen to prevent rot and termite attack.
7. After plastering, hang the shutter with three hinges, leaving clearance of 3 mm all round.

Frames are made of seasoned sal, teak or sisau timber.

General parts and terms

 DOOR                              WINDOW
 +----------------------+          +------------------+
 | head                 |          |     head         |
 | +------------------+ |          | +------+-------+ |
 | |   top rail       | |          | |      |       | |
 | |------------------| |          | | sash | sash  | |
 | |      panel       | |          | |      |       | |
 | |s  lock rail    s | |    jamb->| +------+-------+ |
 | |t  panel        t | |          |      sill        |
 | |y                 y| |          +------------------+
 | |l  bottom rail  l | |
 | +------------------+ |
 | threshold            |
 +----------------------+

Casement, awning and hopper windows

• Casement window: shutters hinged on the vertical side, opening outward or inward like a door; gives full opening for ventilation.
• Awning window: shutter hinged at the top and opens outward at the bottom; allows ventilation even during rain.
• Hopper window: shutter hinged at the bottom and opens inward at the top; directs air up and prevents rain entry.

 Casement        Awning         Hopper
 +--+--+         +------+       +------+
 | /|\ |         | hinge|       |      |
 |/ | \|         |  \ / |       | /  \ |
 +--+--+         +------+       +hinge-+
 side hinge      top hinge      bottom hinge

Bay window: a window that projects outward from the wall line of the building, with three sides (usually 3 shutters at 90 or 135 degrees) forming a bay. It increases floor area, gives more light, a wide view and ventilation, and is used in living rooms and bedrooms.

 PLAN
    ___________
   /           \
  /  bay window \
 ======wall=======

Dormer window: a vertical window built in the sloping roof, with its own small gable or sloping roof. It gives light and ventilation to the attic or room under the roof.

      /\
     /  \
    /[]  \  <- dormer window in roof slope
   /______\

Casement window

Shutters are hinged to the vertical frame side and open like a door, outward or inward. Full area can be opened, so ventilation is good. Used in residential rooms, offices and public buildings; common in Nepal.

Louvered window

Slats (louvres) of wood, glass or metal fixed or movable at 45 degrees in the frame. They allow air but block rain, sun and view. Used in bathrooms, toilets, kitchens, stores and where privacy with ventilation is needed.

Corner window

Placed at the corner of a room where two walls meet, with two casement windows meeting without a corner post. It admits light and air from two sides and gives cross ventilation and a wide view. Used in living rooms, bedrooms and sitting rooms of houses, where a good view is available.

 PLAN of corner window
 wall |_______________
      |   window A    |
 wall |__             |
         | window B   |

Types of windows

Window for more light

A bay window (or a large fixed or corner window) admits the most light because it projects out of the wall and receives light from three sides; the glass area is larger and light comes from different directions. Other good choices are clerestory windows and skylights, which bring light from the roof. A fixed window (picture window) with a full-height glass panel admits maximum light but needs another opening for ventilation.

So for admitting more light, a bay window or full-height glazed casement window is suitable. Window area should be at least 1/10 of the floor area as per building code, and the sill is about 0.9 m high.

A louvered window has a frame in which a number of slats (louvres) are fixed at 45 degrees to the horizontal so that they overlap and keep rain out while allowing air and some light to pass.

 ELEVATION                    SECTION
 +---------------+         frame |  louvres at 45 deg
 |===============|               | //  //  //
 |===============|  louvres      | //  //  //
 |===============|               |
 +---------------+

Components

• Frame: head, sill and jambs (75 x 75 mm), fixed in the wall.
• Stiles: vertical members of the sash.
• Louvres (slats): timber, glass or aluminium strips 150-200 mm wide, 6-10 mm thick, fixed in grooves at 45 degrees with 1/3 overlap; may be fixed or movable by a lever.
• Rails: top and bottom members of the sash.
• Operating device: link rod and handle for movable louvres.
• Fittings: hinges, bolts, wire mesh to keep insects out.

Uses: bathrooms, toilets, kitchens, godowns and factories.

Panelled door

A panelled door shutter has a framework of vertical styles and horizontal rails, with the spaces filled by thin panels of timber, plywood or glass fixed in grooves.

 DOOR                              WINDOW
 +----------------------+          +------------------+
 | head                 |          |     head         |
 | +------------------+ |          | +------+-------+ |
 | |   top rail       | |          | |      |       | |
 | |------------------| |          | | sash | sash  | |
 | |      panel       | |          | |      |       | |
 | |s  lock rail    s | |    jamb->| +------+-------+ |
 | |t  panel        t | |          |      sill        |
 | |y                 y| |          +------------------+
 | |l  bottom rail  l | |
 | +------------------+ |
 | threshold            |
 +----------------------+

Battened door

A battened door has vertical battens (100-150 mm wide, 20-40 mm thick) with tongued and grooved joints fixed to 3 horizontal ledges (150 x 30 mm); in a ledged and braced door diagonal braces (100 x 30 mm) are added.

 |||||||||
 |=======|  ledge
 |||||||||
 |=======|
 |||||||||
 |=======|

A panelled door shutter 1.0 m x 2.1 m is shown below with a frame of 100 x 75 mm and a shutter 40 mm thick.

 PLAN (at jamb)                   VERTICAL SECTION
  wall                               head
  |  +-----frame 100x75-----+        |  top rail 100x40
  |  |  +------------------+|        |  
  |  |  | style 100x40     ||        |  frieze rail
  |  |  |  panel 15-20     ||        |  panel 15
  |  |  +------------------+|        |  lock rail 150x40
  |  +----------------------+        |  panel 15
                                     |  bottom rail 200x40
                                     |  threshold

Details

• Styles and rails: 100 x 40 mm (lock rail 150 x 40, bottom rail 200 x 40).
• Panels: 15-20 mm thick, held in 12 mm deep grooves of styles and rails, free to expand.
• Tenon and mortise joints, glued and wedged.
• Three hinges (100 mm butt hinges) at 150 mm from top, bottom and the centre; bottom clearance 10-12 mm.

Purpose of doors and windows

• Doors: give access to rooms and the building, provide privacy, security and protection from weather, noise, and fire.
• Windows: admit daylight and fresh air, give a view, ventilation, and add to appearance.

Sizing (as per NBC and usual practice)

The door height should leave a head clearance of 2.0 m, and the opening should allow furniture to pass.

Terms used in panelled doors

• Frame (chaukhat): head and two jambs.
• Shutter: the moving leaf.
• Styles: vertical outer members; rails: top, frieze, lock and bottom rails.
• Panels: infilling boards of timber/plywood/glass.
• Muntin: intermediate vertical member between panels.
• Mullion/transom: for fanlight.
• Horn: projection of the frame into the wall.
• Stile mortise and rail tenon joints.
• Hinge, lock and handle.

A door or window is made of a fixed frame and one or more movable shutters, together with fittings.

Components of doors

• Frame (chaukhat): the fixed assembly in the wall that carries the shutter. Parts: vertical posts/styles, horizontal head (top) and sill (bottom, windows and some doors).
• Shutter: the movable leaf that opens and closes the opening. Parts: stiles (vertical), top, middle (lock) and bottom rails, panels, glazing bars and muntins.
• Horns: short projections of the head/sill that are built into the masonry to hold the frame.
• Holdfasts: MS flats (about 30 x 6 mm, 20 cm long) fixed to the frame sides and embedded in the wall/concrete.
• Architrave and lining: a moulded finishing strip around the frame and a board lining the reveal.
• Fittings: hinges, tower bolts, aldrop, handle, lock, stopper, door closer, glass and putty.

 Frame in wall (section)   Part of shutter
  wall | horn               ____________
  ==== |==HEAD===           |__top rail_|
  holdfast->|  |            |s|      |s|
       POST |  |            |t| pane |t|
            |  |            |i|      |i|
                            |_|_bottom_|

Components of windows

• Frame: posts (jambs), head, sill and mullions/transoms in larger windows.
• Sash/shutter: the openable glazed part with stiles, top and bottom rails, glazing bars and a lock rail.
• Sill: the bottom member with a slope and drip groove (throating) to throw rain water out.
• Mullion and transom: vertical and horizontal members that divide a large opening.
• Glass panes, putty/beading, hinges, handles, stays, bolts and window bars/grill.

   +-----------------+   HEAD
   |  sash  | sash   |
   | (glass)|(glass) |  <- MULLION between
   |--------+--------|  <- TRANSOM / lock rail
   |  sash  | sash   |
   +-----------------+   SILL (sloped, drip groove)

Types of doors

 Battened & ledged     Framed & panelled    Flush door
 +------------+       +------------+       +------------+
 |||||||||||| |       |  panel     |       |            |
 |============| ledge |------------|       |  plain     |
 |||||||||||| |       |  panel     |       |  skin      |
 |============| ledge |------------|       |            |
 |||||||||||| |       |  panel     |       |            |
 +------------+       +------------+       +------------+

Functions of doors and windows

Door:

• Gives entry and exit and connects rooms.
• Provides privacy and security.
• Controls light, air and sound, and protects against weather.
• Allows movement of furniture and goods, and escape in fire.

Window:

• Admits daylight and fresh air (natural ventilation).
• Gives view of the outside.
• Helps remove hot, stale air.
• Adds to the architectural appearance.

Elevation of a battened door

A battened door has vertical boards (battens, 100-150 mm wide, 20-30 mm thick) tongued-and-grooved and fixed by two or three horizontal ledges nailed or screwed on the back, with the frame around it.

   +----------------------+  <- head
   |||||||||||||||||||||||
   |||||||||||||||||||||||
   |=====================|  <- top ledge
   |||||||||||||||||||||||
   |||||||||||||||||||||||
   |=====================|  <- middle ledge
   |||||||||||||||||||||||
   |=====================|  <- bottom ledge
   +----------------------+
   <- battens (vertical) ->

Elevation of a glazed window (wooden)

Wooden frame with two glazed sashes, hinged to the posts. Each sash has stiles, top rail, bottom rail and glazing bars holding the glass panes with putty/beading.

   +-------------------------+  <- head
   |+----------+ +----------+|
   ||  glass   | |  glass   ||
   ||----------| |----------||  <- glazing bar
   ||  glass   | |  glass   ||
   |+----------+ +----------+|
   +-------------------------+  <- sill (sloped)
    <- sash ->     <- sash ->

Openings are the doors, windows and ventilators left in a wall.

Functions of openings

• Entry, exit and movement between rooms (doors).
• Natural light and ventilation (windows, ventilators).
• Privacy, security and protection against rain, wind, noise and dust.
• View of the outside and good appearance.
• Emergency escape in fire.

Doors by working operation

1. Sliding door: The shutter slides sideways on rollers along a top (or bottom) track, parallel to the wall. It needs no swing space, so it is used for shops, garages, wardrobes.

  wall  +==============+==============+
        |  fixed       |<-- sliding   |
        |              |    leaf      |
  track =================================

2. Revolving door: Three or four leaves fixed to a central pillar rotate inside a cylindrical enclosure. It keeps the air-conditioned air in and handles heavy traffic (hotels, banks).

        wall |   leaf
         ----+--/--
            ( + )   top view: leaves turn
         ----+--\--  about central pivot

Windows by working operation

1. Casement (side-hung) window: Sashes hinged at the side swing in or out like doors. The most common type, gives full opening.

   +-------+-------+
   | sash  | sash  |   hinges at the
   |  ->   |  <-   |   outer posts
   +-------+-------+

2. Sliding window: Sashes slide horizontally in grooves of the frame (aluminium/UPVC). It needs no swing space, but only half the opening can be open.

Others: pivoted, double-hung, louvred, fixed, bay and dormer windows.

A door is a movable barrier fixed in a wall opening for entry, exit, privacy, security and weather protection. It has a frame and a shutter.

Types by construction

• Battened and ledged door: vertical boards held by horizontal ledges; cheap, for stores and sheds.
• Battened, ledged and braced door: diagonal braces added to stop sagging.
• Framed and panelled door: stiles, rails and panels of wood, plywood or glass; the usual door for houses and offices.
• Flush door: flat faces of plywood over a timber frame; plain and modern.
• Glazed door: panels of glass for light and view.
• Louvred door: fixed or movable slats for ventilation (bathrooms).

Types by working

• Sliding door: moves on tracks, saves space.
• Folding door: hinged leaves fold together.
• Revolving door: turns on a central pivot, used in hotels and banks.
• Swing (double-acting) door: opens both ways, used in hospitals and kitchens.
• Rolling shutter: steel slats rolled on a drum, used in shops.

Doors may be of timber, steel, aluminium, UPVC or glass. Timber must be well seasoned, free from defects and preferably treated (sal, teak, sisau, uttis in Nepal).