Jagvir Goyal
Large sized windows have been in vogue now for many years and these certainly elevate the elevations of the house notwithstanding many aspects related to their provision to be taken care of. Planning large sized windows for a house to be constructed is easy as any size can be chosen and attached structural features can be designed accordingly. Issues arise when the residents want to replace the smaller sized windows with larger ones in the houses already constructed. Let’s have a look at the issues related to replacement of old windows with new and large ones as certain queries related to the issue have landed in our inbox:
The design: The external wall of a room will have either a door and a large sized window in it or simply a large sized window only. It depends on the requirement of the residents if they want to connect the room to the front or back courtyard. In that case, provision of a door has to be planned. Size of the large sized window to be added depends upon the width available after the provision of the door. A door cum window with a common vertical stile in the door-window frame, designated as DW can be provided or there can be masonry between the door and the window frames, the width of masonry depending upon the dimension of the wall. In case no door is planned, a large sized window can be accommodated by replacing the joinery already provided.
The Lintel & the projection: The most important aspect to be taken care of while replacing old windows is to ensure safe provision of RCC lintel and projection on the top of door and window to be provided. In older houses, top of door and windows used to be kept at 6 feet 9 inch level and a lintel and outer cantilever projection acting as sunshade was provided over them. These days, door and window in the outer wall are taken almost up to the ceiling level by adding a ventilator above the door and keeping top level of door and window frames at same level.
Structural safety: RCC lintel provided over the window serves two important purposes. It supports the brick masonry wall provided above it up to the ceiling of the room and also acts as the beam for the projected RCC cantilever acting as sunshade and transfers the load safely to the foundation through the masonry on which it is rested on both sides of the window. Therefore, its safe design and provision shouldn’t be ignored or compromised.
Replacing old lintel & projection: If the width of the window has to be increased from the existing one but the top level of the window is to be kept same as already provided, the lintel and projection above it may have to be replaced, depending upon the extent of width to be increased. In practice, the lintels have a bearing of 9 inch on the walls on each side of the window. If the width of window is to be increased by mere 6 inch, the availability of the balance bearing area for the already provided lintel can be carefully checked to be sufficient. If the width of window has to be increased significantly, a new lintel shall be required for it. If the depth of the window is to be increased, first try should be to increase the depth by lowering the sill of the window to room skirting level and keeping the top level same as already existing. This will help in using the lintel and projection already provided. If the depth of window is increased above the existing top level, the old RCC lintel and projection will have to be replaced with a new one at the new top level. If the window is taken to the ceiling level, a beam at top of window can be provided while the slab, already projecting beyond the wall acts as the shade for it.
Material options: Earlier, wood used to be the only option and thus was the unanimous choice for use in window frames and shutters. In older houses therefore, only wooden windows used to be provided. Now, multiple materials are available, most popular being wood, wooden products, uPVC and Aluminium.
Material choice: Aluminium framed windows don’t look good in the houses and are mostly used in commercial areas. Wooden products tend to wear out or get damaged by harsh weather. The choice therefore narrows down to wood and uPVC only. In case all the windows in the house are to be redesigned and replaced, either of the two materials can be chosen. If uPVC windows are chosen, these can have wooden shades to look like wood and match with the doors already provided in wood. If only one or two windows are to be replaced, better will be to use wood only for maintaining uniformity of material in joinery. One window in UPVC, some doors in wood and another window or so in wood may make an odd looking combination.
Design of window: Large sized windows presently in fashion either have a large fixed glass panel fitted to the frame of the window or have 1 foot 6 inch wide openable shutters on one side and fixed glass in the balance portion. Depth of openable shutters is further restricted by providing fixed glass in the lower panel below it. At the most, 1 foot 6 inch wide openable shutters are provided on either side and central part has fixed glass. In earlier times, windows used to be provided with multiple openable shutters adjacent to one another by providing intermediate vertical stiles. Such windows can be easily replaced with newly designed windows with less number of openable shutters.
Window frames: For window frames, earlier, a section of 4.5 inch x 2.5 inch was used. These days, section of 6 inch x 2.5 inch is prevalent and looks attractive.
Provision of Glass: In large sized windows, it is preferable to provide toughened fixed glass panels. Even for openable part if any, only toughened glass should be provided. Thickness of toughened glass will however vary. Bigger is the panel size, more has to be the thickness.
Provision of grills: Most people don’t prefer providing grills in windows with toughened glass panels. However, provision of sleek and simple geometrically designed grills always lend a feeling of security to the house owner and prove to be a deterrent for the burglars.
