Small moves matter as much as the big ones when it comes to meaningful design, as Himanshu Burte finds in this house in Pune.
Modern Indian life is always a negotiation between traditional and modern forms and values. This negotiation was perhaps edgier for the Khadke family once it decided to move out from the well-known traditional house Raste Wada, in the old heart of Pune, into a new 4,000 sq ft, six-bedroom house for a joint family in a more modern part of the city.
Girish Doshi, the 52-year-old architect, decided to do two things: one, emulate the sociability that the traditional wada design fostered through its shared central courtyard, and two, ensure a comfortable indoor climate by inducing ventilation. The result is an innovatively constructed building inspired by traditional architecture. It also confirms the axiom that ecologically conscious architecture can look as sharp as any other kind.
First steps
The wadas of Maharashtra are basically courtyard houses. Habitable spaces, including on an upper floor, surround a paved open space which is used for a variety of daily functions. This space connects different families living around it through informal contact.
Similarly, the entrance to the wada from the street often has platforms on either side that encourage residents and passers-by to pause for a greeting or gossip. This opportunity for conversation helps bind the residents of the wada to the neighbourhood socially.
In the Khadke house, Doshi took both ideas but transformed them. The entrance gate has two seats flanking the door and older people from the neighbourhood often perch there as their grand-children play on the street. The roof of the gate portal, meanwhile, has grass and creepers planted on it to provide an aura of green at the entrance.
Inside the house, Doshi replaced the courtyard with a double height atrium into which different bedrooms open. The diffused light let in by the glass roof over the atrium recalls the daylight of the traditional courtyard.
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Open-hearted
The atrium is similar to the traditional courtyard also in its ventilating function — but again with a difference. In the usual open-to-sky courtyard the sun heats up the air inside it and makes it rise. The cooler air from indoor spaces around the courtyard is thus pulled into the open, setting off a current of air.
In the Khadke house, the glass roof makes the air in the atrium even hotter than normal because glass traps heat while letting light move in and out. The hot air rises through two ventilating towers beside the glass roof and activates extractor fans which throw it out.
This sets off a draught as cool air from the rooms around it is pulled into the atrium and thrown out by the extractors. The draft is reinforced by breeze harnessed by wind towers that run down from the first and ground floors to the basement.
Wind-catching towers are less common on the Indian subcontinent, but have been used traditionally in Sindh for cooling and ventilation. In the Khadke residence, they are empty shafts that rise well above the roof and have openings in their sides to catch passing breeze. Here these shafts are mainly used for ensuring constant movement of fresh air through the building.
The relatively dust-free air is channeled down the shaft and into adjoining rooms through ‘windows’. That air is then sucked back out of the room because of the draught set up in the atrium. This system of induced ventilation works best in dry climates and when the difference between indoor and outdoor temperature is highest, which is in the scorching summer. That is exactly when it is most needed.
The glass roof over the atrium doubles up as a tabletop on the terrace and is so placed as to work as a buffet counter during parties. The tall wind towers, meanwhile, also solve another old, old problem: the water tanks placed on them provide enough ‘head’ for the water to ensure adequate water pressure in the upper floor showers.
The science of windows
The design of the bedroom windows extends Doshi’s approach of updating traditional details. The windows have two parts. The upper part has wooden shutters that can be fully opened and no grill. The lower part is double-shuttered. The outer shutter is solid wood and the inner shutters have wooden louvers and a mosquito mesh. A steel grill is fixed between them into the frame.
This arrangement allows for different permutations and combinations over the day and enables breeze to move freely through the rooms. By day, the lower window is kept closed and the upper open, letting in light and air freely. Come evening, and the upper window is closed for privacy, while the lower window (with the grill) is kept open through the night letting in cooler breeze while ensuring security. The design allows for privacy, and light control without resorting to curtains that gather dust and require maintenance.
Building techniques
The house looks like any other cement-plastered RCC building. It is, in fact, built using an innovative system developed by structural designer V D Joshi and perfected by Doshi over the last two-and-a-half decades.
At the centre of this system are hollow concrete blocks of different sizes. They are used to build external load-bearing walls stiffened with a little steel at the corners (internal walls are an inch and a half thick in ferrocement and are ‘folded’ in plan to yield cupboards and shelves in each room). They are also used as ‘fillers’ in floor and roof slabs that reduce the amount of cement and steel consumed in construction.
The hollows ensure insulation from the hot outdoors and make the building much lighter, which in turn further reduces the cement and steel used. An added benefit is that Doshi has been able to make the slabs and walls of the same thickness (200 mm or 8 inches) so that there are no columns or beams that project out of corners. Thus the system saves energy intensive material and is therefore eco-friendly and economical. It also enables an elegant architectural expression.