20

DOORS AND WINDOWS

20.1 INTRODUCTION

Doors, windows and ventilators are important and main fixtures in a building which play vital role in the comfortable usage of a building.

Door is a framework with shutters made of wood, steel, aluminium or a combination of these materials (with glass wherever needed), which is secured in an opening left in the wall for the purposes of providing access to the users of the structure. For small openings, door is provided with one leaf or shutter and for larger openings two or more shutters may be provided.

Window is a framework with shutters fixed in an opening left in the wall for the purpose of providing daylight, vision and ventilation. The window shutters may be of wood or glass. All materials used for construction of door may be used for window also.

Ventilator is a window having small heights with shutters pivoted and fixed at the top of the door or window.

Details of doors and windows are discussed in this Chapter.

20.2 TECHNICAL TERMS

Technical terms used in connection with doors and windows are discussed below (Fig. 20.1).

1. Frame

This consists of a group of members which form a support for a door or window.

2. Style

This is the outside vertical member of the shutter of a door or window.

3. Head

This is the horizontal uppermost part of a frame.

4. Sill

This is the bottom horizontal part of a window.

5. Top Rail

This is the topmost horizontal member of a shutter.

Figure 20.1 Different parts of door and window

6. Lock Rail

This is the middle horizontal member of a shutter where the locking arrangements are made.

7. Bottom Rail

This is the bottom most horizontal member of a shutter.

8. Cross Rail

This is also called as intermediate rail which is an additional horizontal rail fixed between the top and bottom rails.

9. Panel

This is the portion of the shutter enclosed between the adjacent rails.

10. Hold Fast

These are used to keep the frame of door or window in position. Three numbers of such hold fasts are fixed on each side of a door frame and two on window frames. They are of mild steel of size 30 mm × 6 mm and of 20 cm length.

11. Horn

This is a horizontal projection of head or sill of the frame beyond the vertical face of the frame. It facilitates the fixing of the frame on the wall opening and is of 10–15 cm length.

12. Shutter

The entire assembly of styles, panels and rails is known as the shutter.

13. Mullion

This is a vertical member which sub-divides a window or a door opening vertically.

14. Transom

This is a horizontal member which is used to sub-divide a window opening horizontally.

15. Louver

This is a piece of timber which is fixed in an inclined position within a frame.

16. Jamb

This is the vertical wall face of an opening which supports the frame of door and window.

17. Rebate

This is the depression or recess made inside the door frame to receive the door shutter.

18. Architrave

When doors and windows are placed flushed with the masonry, a strip of wood usually moulded or splayed is fixed around the sides closing the joint. This gives a decent appearance to the joint of the frame and masonry.

20.3 DOORS

Doors are to be located such that there shall be freedom of movement in and out of the room. Further it should ensure the maximum use of accommodation in the room and at the same time privacy of the occupants.

In general, it is preferred to place the door at one end of the room. If there happens to be two doors, they are to be located in the opposite walls of the room. This provides good ventilation and also creates least interference with the inside arrangement of the room.

20.3.1 Standard Sizes of Doors

Dimensions of doors and windows are measured inside to inside of openings. Door is designated as 8 DS 20 in which D denotes door and S denotes single shutter. The first number indicates the width of opening in module of 100 mm. The last number denotes the height of the opening in module of 100 mm.

As discussed above, 8 DS 20 refers to Door with single shutter of width 800 mm (= 8 × 100) and height 2000 mm (= 20 × 100). Standard sizes of doors as per Indian Standards are shown in Table 20.1.

Table 20.1 Indian standard dimensions of timber door frames

* Doors with two shutters 560 mm each shutter and 20 mm overlap when closed.

20.3.2 Materials Used

Wood, metals and concrete are used for door frames where plywood and glass are used for door shutters/panels.

1. Wood

Wood is used in several forms for the construction of doors. As wood is largely available in India, it is mostly used in India. Doors may be made of solid planks or built up of small individual pieces. Further, it can take a good polish and can be moulded to produce an attractive appearance. One set back of wood is that it is easily attacked by vermin.

2. Metals

Metal doors, particularly aluminium, have been in use in different forms. Cast metal doors are generally preferred. Hollow metal doors made up of a metal frame and covered with sheet metal have high resistance, life and fire resistance.

3. Concrete

In situations where there is a danger of vermin, reinforced cement concrete frames are preferred.

4. Plywood

This is used for flush doors which have a wide variety of finishes.

5. Glass

In order to permit light, glasses are used in panels. Further, to get a rich appearance, big openings in doors are fitted with thick glass sheets. Coloured glass, frosted glass and beaded glass can be used for ornamental appearance.

20.3.3 Types of Doors

Based on the type of materials, positioning of different components, method of construction, intended purposes, etc., the common types of floors used in the building are discussed below.

1. Ledged Doors

A ledged door is formed by joining the vertical boards (battens) and horizontal supports (ledges) securely by suitable joints (Fig. 20.2). The battens are of 10–15 cm wide and 20–30 mm thick, whereas the ledges are of 10–20 cm wide and 30 mm thick. Top, middle and bottom ledges are used. Shutter is hung on T-hinges which are fixed to the ledges. This is the simplest form of door. It is used where strength and appearance are not very much important.

2. Ledged and Braced Doors

These doors are similar to the ledged doors discussed above but for the difference that diagonal members, known as the braces, are provided as shown in Fig. 20.3. The braces are generally of 10–15 cm wide and 30 mm thick. The braces provide rigidity and for this reason such doors are preferred for wide openings. The braces are usually housed in the ledges. It is to be noted that the braces should work in compression and not in tension.

Figure 20.2 Front elevation of ledged door

Figure 20.3 Back elevation of a ledged and braced door

3. Ledged and Framed Doors

In this type of doors, a framework for shutter is provided. This makes the door stronger and better in appearance as shown in Fig. 20.4. Styles are of 10 cm wide and 40 mm thick. As usual the battens and ledges are provided.

Figure 20.4 Front elevation of ledged and framed door

4. Ledged – Framed and Braced Doors

This type is similar to the one discussed above but for the difference that the braces are introduced (Fig. 20.5). As this type of door is strong and durable, this can be adopted for external use. The braces should incline upwards from the hanging side.

Figure 20.5 Elevation of ledged – framed and braced door

5. Framed and Panelled Doors

Panelled doors are mostly used. It consists of a framework in which panels are fitted. The styles are continuous from top to bottom and rails are joined to the styles. Mullions, if any, are joined to rails. The thickness of the shutter depends on various factors such as type of work, situation of the door, number of panels, etc. The thickness of the shutter is about 30–40 mm and the thickness of panels is about 20 mm. Panels are secured in position by the grooves inside the edges of the framework. Figure 20.6 shows panelled doors with panels. Moulding of panels adds to the beauty. Number and size of panels depend on the desire of the owner.

Figure 20.6 Elevation of framed and panelled doors

For small openings, single shutter may be adequate while double-leafed shutters are used for large openings.

6. Glazed or Sash Doors

When there is a need for more light in a room, glazed doors may be preferred. Partly panelled and partly glazed doors may be considered while some light is already available through glazed windows.

Usually the ratio of glazed portion to the panelled portion is 2 : 1. The glass is fixed into the rebates made in the wooden sash bars and secured by nails and putty or by wooden beads (Fig. 20.7).

In order to increase the area of the glazed portion, the width of styles above lock rail is decreased as shown in Fig. 20.7. These are known as the diminished styles or gunstock styles. Glazed or sash doors are preferred in hospitals, offices, libraries, show rooms, etc.

Figure 20.7 Fully and partially glazed and partially panelled doors

7. Flush Doors

A flush door comprises of a framework of rails and styles and covered with plywood or hardboard. There are two types of flush doors, viz., a framed flush door and a laminated flush door.

A framed flush door consists of styles, rails, horizontal ribs, vertical ribs and plywood (Fig. 20.8(a)). For ventilation purposes, holes are provided in horizontal ribs. The vertical ribs rest on rails. Hollow space is also filled sometimes by granulated cork or any other light material. In order to fix the hinges and mortise lock, hinge and lock holes are to be provided. These doors are light and cheap but weak and not durable.

A laminated flush door consists of styles, rails, laminated core and plywood (Fig. 20.8(b)). Under great pressure the laminae of wood are glued. Along with the plywood, sheets on either side are also glued to the laminated core under great pressure. Evidently these doors are heavy and durable.

8. Louvered Doors

Louvers are provided in the shutters which may be fully or partially louvered. Further the louvers may be movable or fixed. Figure 20.9 shows a movable type partially louvered door. Louvers are arranged at such an inclination that the horizontal vision is obstructed. That is the upper back edge of any louver will be higher than the lower front edge of the louver just above it. In the movable louvers, a vertical piece of timber is provided to which the louvers are attached through hinges. With this vertical piece, the movement of louvers can be performed. Louvers may be of glass or wood (Fig. 20.9).

Figure 20.8 Types of flush doors

Figure 20.9 Movable louvered doors

Louvers provide free passage of air in the closed position and at the same time maintain sufficient privacy. Such doors are preferred in sanitary blocks of public buildings, residential buildings, etc. However, the louvers should be cleaned often failing which dust may accumulate.

9. Wire-gauged Doors

These doors permit easy passage of air into the room. Further prevent movement of flies or insects. They are made of vertical and horizontal styles into which wire gauge is fixed. They may be provided on a separate frame or hung (Fig. 20.10).

Styles and rails shall be of the same size similar to other doors. The wire gauge shall be of best quality woven wire webbing. These doors may be of double-leaf type.

Figure 20.10 Elevation of wire-gauged door

10. Revolving Door

In a revolving door, a central support is provided to which four radiating shutters are fixed (Fig. 20.11). The shutter may be glazed, fully or panelled or partially panelled, or partially glazed. At the bottom of the shutters, called rubbing ends of the shutters, are rubber pieces fixed to prevent draught of air. The arrangements of shutters are made in such a way that the shutters may be folded and the opening can be closed. A revolving door simultaneously provides entrance on one side and exit on the other end (Fig. 20.11).

Figure 20.11 Revolving doors

20.4 WINDOWS

Windows made of materials as that of doors and fixed to the wall openings for admission of light, free circulation of air, etc. They comprise of a frame which is fitted in the opening in the wall and small shutter frames containing glass, wood, etc., are attached to the frame by hinges. Window shutters have different types of movements.

20.4.1 Window Shutter Movements

Windows have different types of movements of shutters which are discussed below (Fig. 20.12).

Figure 20.12 Type of window shutter movements

1. Fixed Type

In this type, the framework is fitted with a glass and the framework can not move.

2. Opening Outside

In this type, the shutters open outside of a building.

3. Opening Inside

In this type, the shutters open inside a building.

4. Top-hinged

The shutter is hinged at the top and can be moved outside.

5. Bottom-hinged

Here the shutter is hinged to the bottom of the frame such that it can be moved inside.

6. Pivoted

In this type, the shutters are made to rotate about a pivot which may be fixed to the window frame. The windows can rotate vertically or horizontally based on the position of the pivot.

7. Sliding

In this type, the shutters can move inside the walls vertically or horizontally.

8. Double Hung

In this type, one shutter goes up and the other moves down.

20.4.2 Types of Windows

Different types of windows are discussed below.

1. Casement Windows

Casement window is one in which the shutters open like doors. This window comprises of a frame consisting of styles, top rail and bottom rail. Window frames are made similar to frames of doors but all the windows are provided with sill at the bottom. The construction is similar to the door construction (Fig. 20.13).

Figure 20.13 Casement window

2. Double-hung Windows

This window comprises of a pair of shutters which can slide within the grooves provided in the frame. A pair of metal weights is provided for each sash with connected cord or chain over a pulley. When the weights are pulled, the shutters open to the required level and thus provide ventilation.

3. Pivoted Windows

This is similar to casement window except that no rebates are provided and the shutter movement is different. Here, the shutters are allowed to swing round pivots. The windows may be pivoted horizontally or vertically (Fig. 20.14). These windows admit more light than side hung windows and easy to clean.

Figure 20.14 Vertically pivoted window

4. Louvered Windows

In this type of windows, louvers are provided as in case of louvered doors. They provide adequate privacy apart from allowing free passage of air. Here, the shutter consists of top rail, bottom rail and two styles which are grooved to receive the louvers. Angle of inclination of louvers is 45° and are fixed in position. If it is expected to move the louvers some mechanism has to be provided to operate. In order to prevent the entry of rain water, the louvers should slope downward to the outside.

5. Sliding Windows

Here the shutters move on roller bearings, either horizontally or vertically. Suitable opening are provided in the walls to receive the shutters when windows are opened out. Such windows are preferred in trains, buses, bank counters, shops, etc.

6. Glazed Windows

These windows are fully glazed casement windows. In order to receive glass panels, sashes are rebated. The glass is kept in position either by putty or by small fillets, known as glazing beads.

7. Metal Windows

Metal windows, made of mild steel, bronze, aluminium or alloys, are widely used these days. Steel windows are manufactured in standard sizes. The metal frame may be fixed directly to the wall (Fig. 20.15) or it may be fixed on a wooden frame. In the former case, the hinges and plugs are provided to keep the frame in position and in the latter case the screens are used to fix the metal frame with the wooden frame.

Figure 20.15 Metal window fixed to wall

8. Corner Windows

These are the windows which are placed at the corner of a room. These windows have two perpendicular faces. Because of such provisions, there is adequate entry of light and air from two directions. Further, it adds to the appearance of the building (Fig. 20.16).

Figure 20.16 Corner window

9. Gable Windows

These windows are provided at the gable ends of a roof as shown in Fig. 20.17.

Figure 20.17 Gable window

10. Dormer Windows

These are the windows which are provided on the sloping roofs. The main purpose of providing dormer windows is to admit light and air to rooms which are constructed within or below the roof slopes (Fig. 20.18).

Figure 20.18 Dormer windows

11. Bay Windows

These windows project outside the external walls of a room. The shape may be square, splayed, circular, polygonal or of any shape. Figure 20.19 shows a splayed bay window. The projection of bay windows may start from floor level or sill level. These windows increase the opening area and admit more light and ventilation. Also adds to the appearance.

Figure 20.19 Bay window

12. Clerestory Window

These windows are fixed near the top of the main roof (Fig. 20.20). Pivoted windows are used for this purpose. These windows provide ventilation to the inside of the room which is blocked by a verandah. It should be noted that the upper part of the shutter opens inside and the lower part opens outside, otherwise rainwater may enter the room. As the window is horizontally pivoted, it can be opened or closed by use of two cords, one attached to the top rail and the other to the bottom rail of the shutter.

Figure 20.20 Clerestory window

20.4.3 Standard Sizes of Windows

In a building, the top of the doors and windows are placed at the same level. Thus the height of a window depends on the height where the window sill has to be fixed based on the circulation needed inside the building. Width of windows depends on the opening required.

The 10 WT 12 designation represents a double shutter window of 1000 mm (= 10 × 100) width and 1200 mm (= 12 × 100) height. Table 20.2 shows the Indian Standard Windows.

Table 20.2 Standard dimensions of timber window frames

20.5 VENTILATORS

A ventilator is a narrow window of small height which is generally fixed at the top of door or window or near the roof of a room for providing ventilation in the room. Ventilator may be fixed which provides only light, whereas the movable ones provide light and air circulation.

Ventilators are provided with glass panels and steel grill is fixed for safety conditions.

Indian Standard Code designates ventilators as 6V6. This represents a ventilator of 600 mm (= 6 × 100) width and height of 600 mm (= 6 × 100). Table 20.3 shows the Indian Standard ventilator frames and shutters.

Table 20.3 Standard dimensions of timber ventilators

Note: Thickness of the shutters are 20, 25, or 30 mm depending on size of the opening.

The shutter of the ventilator is horizontally pivoted and can be opened or closed by use of the chords, one attached to its top rail and the other to the bottom rail.

1. Doors, windows and ventilators are important and main fixtures in a building which play vital role in the comfortable usage of buildings.
2. Door is a framework with shutters made of wood, steel, aluminium or a combination of these materials (with glass wherever needed), and is secured in an opening left in the wall for the purposes of providing access to the uses of the structure.
3. For small openings, a door is provided with one leaf or shutter and for large openings two or more shutters may be provided.
4. Doors should ensure the maximum use of accommodation in the room and at the same time privacy of the occupants.
5. Dimensions of doors and windows are measured inside to inside of openings.
6. A ledged door is formed by joining the vertical boards (battens) and horizontal supports (ledges) securely by suitable joints. This is the simplest form of door.
7. Ledged and braced door is similar to ledged door but for the difference that diagonal members, known as braces, are provided. It is to be noted that the braces should work in compression and not in tension.
8. Ledged and framed door is one in which a framework for shutters is provided. This makes the door stronger and better in appearance.
9. Ledged-framed and braced door is similar to ledged and framed one but for the difference that additional braces are introduced diagonally.
10. Framed and panelled door is one in which panels are fitted to the framework. Moulding of panels adds to the beauty of the doors.
11. When there is a need for more light in a room, glazed doors may be preferred. Partly panelled and partly glazed doors may be considered while some light is already available through glazed windows.
12. A flush door comprises of a framework of rails and styles and covered with plywood or hardboard. There are two types of flush doors, viz. a framed flush door and a laminated flush door.
13. Louvered door is one in which louvers are provided in the shutters. Louvers may be movable or fixed type and the door may be partially or fully louvered.
14. Wire-gauged door permits easy passage of air into the room. Further it prevents movement of flies or insects.
15. In a revolving door a central support is provided to which four radiating shutters are fixed. The shutters may be fully glazed, panelled or partially panelled and partially glazed.
16. Window is a framework with shutters, fixed in an opening left in the wall for the purpose of providing daylight, vision and ventilation. The window shutters may be wood or glass.
17. Windows have different movement of shutters, viz., fixed type, opening outside, opening inside, top-hinged, bottom-hinged, pivoted, sliding and double hung.
18. Casement window is one in which the shutters open like doors. The window comprises of a frame consisting of styles, top rail and bottom rail.
19. Double-hung window comprises of a pair of shutters which can slide within the grooves provided in the frame.
20. Pivoted window is similar to casement window except that no rebates are provided and the shutter movement is different. Here, the shutters are allowed to swing around pivots.
21. In louvered windows, louvers are provided as in the case of doors. They provide adequate privacy apart from allowing free passage of air.
22. Sliding windows shutters move on roller bearings, either horizontally or vertically. Suitable openings are made in the walls to receive the shutters when windows are opened out.
23. Glazed windows are fully glazed casement windows. In order to receive glass panels sashes, are rebated.
24. Metal windows made of mild steel, bronze, aluminium or alloys are widely used at present. Steel windows are manufactured in standard sizes. The metal frame may be directly fixed to wall or it may be fixed on a wooden frame.
25. Corner windows have two perpendicular faces placed at the corner of a room.
26. Gable window is provided at the gable end of a roof.
27. Dormer window is provided on the sloping roof. Main purpose is to admit light and air into the room which is constructed below the roof.
28. Bay window is projected outside the external wall of a room. The shape may be square, splayed, circular, polygonal, etc.
29. Clerestory window is fixed near to the top of the main roof where the ventilation is blocked by the verandah.
30. Ventilator is a narrow window of small height which is generally fixed at the top of door or window or near roof of a room for providing ventilation in the room.

1. How are doors and windows designated by Indian Standards?
2. Write a note on the materials used for making doors and windows.
3. What are the different types of ledged doors? Explain with neat sketches.
4. Name the important components of a panelled door. Why would you recommend the bottom sill for external doors?
5. What are the advantages of flush doors?
6. Under what situations louvered doors are preferred? Explain.
7. It is intended to provide a partially panelled and partially glazed door for a 1.20 m wide and 2.40 m high opening. Suggest a suitable door and sketch the door with all details.
8. Name the various types of windows. Draw an elevation and vertical section of a casement window.
9. Draw an elevation and a vertical section of a casement window.
10. Why the metal windows are preferred to wooden windows?
11. Bring out the necessity of providing dormer window and bay window.
12. What are the standard sizes of windows? Explain.
13. List the precautions to be taken in case of aluminium windows.
14. Explain the various factors to be considered while locating the location of doors and windows.
15. What are ventilators? Explain their uses. Mention the standard dimensions of timber ventilators.
16. What are the points to be observed in case of natural ventilation?
17. Explain the requirements of a good ventilating system.
18. Explain the meanings of the following designations as recommend by Indian Standards.

    (i) 8 DS 20

    (ii) 6 WS 12

    (iii) 10 WT 12

    (iv) 12 DT 21

    (v) 12 V 6