Projected Opening Systems in Buildings

PROJECTED OPENINGS SYSTEMS in BUILDINGS:  Opening Systems have transgressed the nominal edge of the architectural form. Such outward, and occasionally the inward push occur on the wall faces, roofs, corners and floors. Examples of forms of wall face transgressions are: Oriel, Bay-window, Bow-window, Zarokha and Mashrabiya. Some of the important reasons are: Emphatic architectural expression, Enlargement of the interior space, Greater opening size (for wider view illumination, solar gain, and aeration), and Facility to have sideways view.
 
ORIEL:

Maison des Quakers Belgium

Bay Window Maison Pfister Colmar

Oriel windows are a form of polygonal bay windows. Oriel windows have a larger perimeter and so allow wider view of the outside. Oriel windows increase the floor space without increasing the footprint (extent) of the building. Oriel windows are usually placed on the upper floors of the building, but siting on ground floors is not uncommon. The windows are projected bays, supported off the base-wall by columns, piers, corbels or brackets.

• The word oriel is derived from Anglo-Norman oriell and post-classical Latin oriolum, both meaning gallery or porch, perhaps from classical Latin aulaeum, curtain.

Oriels have of many forms: Sill is at the floor level, seat level or mid body level, the head-side of the projected gap terminates at lower position, such as at human head level or reach to the ceiling level of the room. Some oriels are partly or wholly glazed and are known as oriel windows, latticed forms are found in Indian Zarokha and in mid East or Arab architecture as Mashrabiya. In both the cases the lattice reduces the glare and provides privacy. Zarokha is more commonly made of stone work, and Mashrabiya have carved wood latticework and often stained glass.

Oriels developed in the 15th C, when under the Tudor kings peace prevailed in England, Wales and Ireland. The prosperity of the great landowners, aristocracy and  Church supported new constructions. Though Italy was seeing revival of classical architecture, Tudor style was mainly local. Merchants and artisans, generally living over the shop in a narrow and tightly-packed town houses, added space by building storeys. The upper storeys were projected out over the street. This encroachments often resulted in extremely dark streets. Timber-framing despite the fire risk, was popular. Oriel windows were also placed over gateways or entrances to manor houses and public buildings. Oriel windows once again became popular during the revival of Tudor style in the 19th and early 20th C, and during Gothic revival (1740).

BAY WINDOWS:

Bay Window
Carved balcony, Mehrangarh Fort, Rajasthan, India

A bay window is an exterior projection of room space, forming a bay of square or polygonal shape. The round (segmental) shaped windows are called bow-windows. Bay windows became popular with Victorian architecture (1870's). A typical bay window consists of three windows, the middle unit is parallel to the house and adjoining two units are set at 30 to 45 degree angles. Bay windows are created: to increase the illumination, provide a wider view of the outside and enlarge the interior space. The bay windows are used on sunny sides in colder climates, over sections facing road side, garden and other natural scape.There are three basic types of bay windows. In full bay windows the opening stretches from floor to ceiling level to create a nook in a room. In half or part bay window, the window starts at seat or nominal sill level and reaches head height level or full ceiling level. In the third version the bay is more of a flower box projecting out. The nook created by the full bay window is well illuminated and has better view of outside so it is used as study area, breakfast space, solarium, hobby area, etc. For these purposes the inner ledge of the bay window is used as built-in seat.

• The building act of 1707 in London and other towns of England did not allow projections on a roadside, to prevent spread of fire along the wall. This was changed in 1894 so that windows were not required to be flush with the exterior wall. During the Victorian and Edwardian period houses began to have bay windows.

BOW WINDOWS:

 Groothaert Boulevard De Smet de Nayer Bow Window

A bow window, is a curved or polygonal bay window. Unlike the bay window, there is no middle window unit, parallel to the room. Instead several small width window units (fixed and shuttered) are joined to form a bow shape. Bow windows first appeared in the 18th C in England and in the Federal period in the USA. Bow windows are also called compass window and radial bay windows.

ZAROKHA or VIEW-BAITHAK (seat) WINDOW:

Adalaj Stepwell, Ahmedabad, India

A Zarokha or Baithak (seat) is a raised platform than the room floor. The raised Zarokha has one facing opening same or slightly larger then the gap in the wall. Adjacent to this, at right angles are two smaller openings. Zarokha has short height tapering parapet, and two small height columns.  The projecting platform and the can accommodate two or more people. The wall gap or the top of the tapered parapet was covered with a lattice of Bamboo, wood, metal or stone.  The Zarokha is an ornamental element that was well placed in the architectural composition.

The Zarokha originated from the Gokh or Gavaksh (Sanskrit), a form of articulated wall niche for storage. It became more of an opening or  window form. It was placed on exterior side of building facing garden, estate, or busy street. During 8th and 11th C AD., during the peak of Hindu architecture, it reached its classical prime. The Zarokha in many ways compensated the need for an intermediate element like verandah in tropical architecture. It created a private domain, accessible from interior compared to a verandah. The Zarokhas covered with a lattice reduced the solar glare and heat gain. Latticed balconies were readily adopted by the conservative Mughals and Rajputs to provide privacy for their women folk.

The Zarokha and such window forms were further refined as Chhatri (pavilion) and other roof level facilities. Large openings were appended with half Chhatri form, made up of two delicate columns and a partly pyramidal roof of straight, concave or convex surfaces. Jali (Lattice) as a filler screen was made of sand stones, marbles or wood, carved with  geometric or floral patterns. Jalis were strongly divided by mullions and transoms. Jalis were punctured with small clear openings such as in Hawa Mahal, Jaipur, India. Jalis were primarily used to curtail the glare but were also used to cascade the flowing water from fountain channels to moisturize the air.

MASHRABIYA:

Mashrabiya is a projected window on second or higher floor, in buildings mainly the urban setting. Mashrabiya are used in houses and palaces although sometimes in public buildings such as hospitals, inns, schools and government buildings. It is commonly placed on the street side, but occasionally on the internal courtyard 'sahn' side. Mashrabiya windows are presumed to have evolved during 12th C in Baghdad. Iraq and Egypt are two countries where many examples survive. They are more common in Eastern (mashriq) parts of the Arab world then the western (maghrib) parts. Basra is often called the city with Mashrabiya. It was introduced in France from its colonial sources, and called moucharabieh.

Mashrabiyas are enclosed with carved wood latticework, composed of the lathe turned wooden sections (bobbins), in complex patterns. Smaller lattice openings in the lower section obscure vision from outside and reduce the air draft, whereas larger openings in the upper parts allow better air draft and illumination. Lattice design differs from region to region.

Mid part of the Mashrabiya is provided with sliding or a side-hung shutter for a clear opening. Mashrabiyas are also lined with stained glass to form an enclosed balcony, and an independent space attached to a room. Shanashil is net or wood screen-covered verandah or porch over looking a street or garden. Mashrabiya in farm houses and for out of the town buildings are more open, with reduced amounts of lattice work and without the lining of glass. Egyptian Mashrabiya projects out at a slightly raised level providing for a Dakkah (a Dakkah is a masonry platform attached to the front part of a house, covered with a rug, it is used for informal talk and tea in Arab rural areas, an arrangement similar to Ota or Otla in a traditional Indian house) or in front of the window, similar to the Indian Zarokha.

Mashrabiya adds space to rooms on the upper floor without increasing the foot print area of the building, but these have also been used for correcting the shape of upper floor front room. Mashrabiya allows air from three sides to enter, even if the draught outside was parallel to the house facade, on the other hand it serves the street and in turn the neighbourhood. Mashrabiya also provides shade for the ground floor windows.

• The word Mashrabiya has varied origins. Mashrabiya denotes drinking or absorbing. The name perhaps has derived from a wood lattice enclosed shelf located near a window to cool the pots of drinking water. The shelf evolved until it became part of the room with a full enclosure. Mashrabiya also has originated from verb Ashrafa =to overlook, ignore  or to observe.

.