It is unbearably hot with no sign of let up. As for rains, it seems to be playing hide-and-seek. The blame game of course points to greenhouse gas effects. While carbon emissions and eroding tree cover are the commonly referred contributors, ever wondered if design of our buildings too could have played a role?
The modern buildings in our cities increasingly display extensive use of glass. Viewing them, one would think the design was for a colder temperate zone, having erroneously found its way into the tropical setting. Not only glass features in copious measure, the designs as well as materials used are out of context, least structured to address heat generation.
A look back at our vernacular architecture reveals plenty of sensibility in not just use of materials but also design. The large overhangs with expansive verandahs around the house ensured heat ingress into the interiors was minimal. The sloped terracotta tiles further kept the heat at bay. The exposed stone or brick walls reduced the heat reflected off their surface and on to the surrounding exteriors.
Free flow of airThe omnipresent internal courtyards not only brought in plenty of natural light but also ensured free flow of air, keeping the interiors cool. Greenery and water bodies were part of every building, again reducing heat.
Cut to the present and it is clusters of multi-storeyed buildings wrapped in glass or other synthetic materials that reflect heat, creating heat islands. The spaces between buildings too have become negligible, preventing free movement of air, compounding the heat inside. As for green cover, it is non-existent. The unfortunate eventuality is the increasing use of air conditioners, which only adds to the heat islands created.
Says architect Leena Kumar, Chairperson, Indian Institute of Architects, Karnataka Chapter, “Architecture needs to be climate responsive and culturally sensitive, reducing dependence on mechanical means of cooling, lighting and ventilation. All mechanical means generate heat. Viewing architecture as an independent entity without concern for the city at large is irresponsible.”
Bad urban planningShe further adds that heat island is the expected consequence of rapid urbanisation and bad urban planning promoted by the city’s bylaws. “Our laws permit crowding and dense placement of multi-storeyed structures that cut free movement of air. This needs urgent change. With computer simulation and 3-D modelling it is not difficult to map the city, its density, floor area ratio, building height, to frame bylaws that take into account movement of air, sunlight, visual vistas, area of earth and green cover necessary for comfortable living conditions.”
Besides bad urban planning and overcrowding of multi-storeyed buildings along with eroding green cover, the tarred roads of urban areas are immense heat generators, reflecting heat intensely, she avers. According to Kumar, presence of greenery and water bodies has a significant impact on cutting the heat reflected by building materials as well as heat generated by buildings as “green cover and water absorb heat significantly.”
She contends that while a major portion of building materials reflect heat, natural materials like stone and exposed bricks have a laser reflection index. “Natural stone absorbs heat but releases it very slowly, keeping interiors cool during the day.”
Referring to vernacular design sentiments, Kumar says, “The erstwhile sloped terracotta tiled roofs were non-heat generating as the clay absorbs some amount of heat while the internal courtyards and high ceiling of these buildings ensured the interiors were cool.”
Concurring with Kumar, architect Dinesh Verma of ACE Group laments that the reduced construction time currently sought has accentuated heat generation by buildings besides their location insensitive designs. “Modern buildings use extensive amounts of metal and glass that permit speedier completion. These not only prevent interior insulation but also generate and transfer tremendous amount of heat inside.”
Good optionsVerma advocates not only context-sensitive designs and greater use of natural materials in construction but also increased green cover to cut down the internal as well as external heat. “Even a simple kitchen terrace garden can cut down heat gain from the roof. Natural materials, especially for walls in the west and south, and use of terracotta hollow blocks are good options.”
While these address heat generation by buildings, Verma contends that the green cover in urban public spaces needs to be brought back, besides resorting to pebbled and landscaped pathways in exterior areas of buildings instead of the ubiquitous concrete “that is increasingly seen currently.”
