By Shubhangi Shah
Benny Kuriakose’s father was very proud that their house, built in the ’60s, was one of the first concrete, flat-roofed houses in their village in Kerala. “You can imagine how such a building fares in a region with torrential monsoons and hot and sweltering weather,” he says.
“In the heat, the house turns into an oven and is almost uninhabitable, and when it rains, it leaks constantly,” he says, adding: “It is funny that even half a century later, we seem to have not learned that, maybe sloping roofs, built with locally-sourced materials and with adequate sun shading, may be the best solution.”
Kuriakose, who runs Benny Kuriakose & Associates, an architectural and conservation consultancy firm based in Chennai, attributes it to “India’s tendency, due to its post-colonial mentality, to look at the West and try and imitate their mode of living”.
The weather is becoming a bit pleasant now. However, it was not too long ago when India was reeling under the sweltering heat, with temperatures at several places, including New Delhi, reaching 50°C. Not just that, the country experienced 280 heat wave days from March 11 to May 18, the highest in 12 years, according to the State of India’s Environment report released by Down To Earth magazine of the Centre for Science and Environment (CSE). The Indian Meteorological Department (IMD) releases the data for heat wave days in individual states every year. The report added them up to come up to a single figure to compare with previous years. For example, the year 2011 saw 40 heat wave days. Several factors, such as the use of fossil fuels and deforestation, among others, lead to a rise in temperature. But is the modern architecture, characterised by high-rise flat-roofed buildings made with the widespread use of glass and concrete, to be blamed too?
“Climate change poses an existential threat, and buildings are a major contributor,” says Kuriakose, who is worried about the extreme heat we have been experiencing. The designer expresses “shock” at the “tall glass-covered buildings being put up across the city”. “I think people often look towards the Gulf states and the West when designing and building these tall buildings and rely on technological fixes when combating the heat,” he says, interjecting that “what we have to understand is that technology cannot compensate for poorly thought out design”.
With urbanisation, we have witnessed a major uptick in construction activities. “In urban India, we often do not take into consideration factors such as context, climate and locally available materials while constructing a building,” says Rahul Kadri, partner and principal architect at Mumbai-based IMK Architects. “The construction materials used today, such as concrete, asphalt, steel, and brick, tend to absorb more heat during the day resulting in a hotter microclimate. Urban heat islands result in heavy dependence on mechanical ventilation, which has resulted in increased energy consumption,” he explains.
“There is no denying that glass is being extensively used for all building typologies—whether it is the exteriors or interiors, which is turning them into a heating furnace,” says Varsha Jain, principal architect and founder, Creative Architects & Interiors (CAI), Chennai. “The extensive use of glass has never been an option for the climatic context of India. It is unsuitable,” she adds. Explaining this phenomenon further, Vijay Dahiya, partner at team3, a Delhi-based architecture and design firm, says that the use of glass and the design of our building envelopes prioritise internal comfort, often neglecting its impact on the external temperatures. “Highly reflective surfaces like glass result in heat being reflected into its surroundings, leading to densely constructed areas having temperatures a few degrees higher than in outer areas of the city,” he adds.
“Most of our modern architectures are imitations of western designs which are characterised by glazing,” says Kadri. “This design scheme has been widely adopted in India without considering the climate difference,” he adds.
Regarding the same, Jain says that it is “the modern movement” that “changed the language of architecture altogether”. “Materials like concrete and glass fulfilled the need for quick and efficient construction while representing the aesthetic of that time. The movement had its influence in India as well,” she explains. However, it is not just an Indian but a “global phenomenon”, she feels.
Take Dubai, for instance. It has an extremely hot and dry climate. “Nevertheless, we see elaborate glass structures that look elegant and aesthetic but play a huge role in today’s climate change. A similar situation is seen in the other parts of the world too, clear through reports that the construction industry is responsible for 37% of carbon emissions in the world,” Jain says.
Dahiya believes that the use of glass is “more than just a trend”. “Its selection is based on its performance criteria and its ability to create a sealed internal environment. It is also an effective material in cold climates,” he says, adding: “Beyond trends, building envelopes need to be designed to respond to India’s climate zones.”
On the same lines, Kadri explains that if climatic parameters are considered, and glass facades are specified accordingly, we can adopt glass as a material to suit India’s climate. For example, the glass specifications recommended by green building codes can reduce the energy consumption of the building.
Jain concurs, saying that glass has some “phenomenal” properties, such as “it lets light penetrate, enabling excellent visual connectivity within spaces”. “However, the key to using this material is its strategic and optimum use,” she adds. Both she and Kadri recommend avoiding its use on the southern side. “This direction receives harsh sunlight. On the other hand, a glass facade in the northern direction provides optimal light,” Kadri explains.
The use of concrete, which absorbs heat, appears to be another environmental issue in modern buildings and architecture. “We know that concrete roofs exposed to the sun and rain are not durable and develop leakage over a while,” says Kuriakose, who thinks that one of the biggest issues is our over-reliance on concrete.
Kadri explains that concrete is a high carbon-emitting material. Also, cement production is extremely energy- and fossil fuel-intensive, making it a ranking producer of carbon dioxide emissions contributing to global warming. “Not just that, when we break down concrete, it is impossible to be reused for construction again,” the architect adds.
So why is it used? “We know it is unsustainable and not terribly long-lasting, but it is cheap, and most people are not proposing viable alternatives to it,” answers Kuriakose. Similarly, Jain explains its use, saying, “Just like glass, the use of concrete is inevitable due to its easy availability and quick, strong and comparatively economical construction.”
The way forward might be the use of composite material, she says. So, instead of building the entire structure in concrete, you use materials like aerocon blocks or concrete hollow blocks, which can help the buildings breathe and insulate them from extra heat gain, she explains. “For example, in one of our projects, SC Shah Bhavan in Chennai, infill slabs, using a mix of earthen pots, along with concrete as a weathering course, work as an efficient passive construction technique that aids cooling. Also, cross ventilation has been provided to make the space naturally comfortable,” she says.
Although people are coming up with alternatives to concrete, it might take some time, suggests Dahiya. “Concrete has taken over the construction industry and is difficult to replace. Its use can be controlled to a large degree in low-rise buildings, but as an industry, we are only beginning to explore viable alternatives for mid- and high-rise structures,” he explains.
What exacerbates heat
Aluminum cladding can also significantly exacerbate heat, the architects opined. Another is the use of air-cooled HVAC units, which release hot air into the building’s surroundings, they added. The use of steel is not an environmentally sound practice either. Heating it up to melt into new material requires a massive amount of energy, explains Kadri. Although recyclable, the process consumes a lot of energy, which comes from fossil fuels. “You can reuse steel, but it still hurts the environment,” the architect explains.
“Similarly, excessive use of metals, glass, concrete and certain compounds of plastics like PVC, make it harder to cope with India’s sweltering climate,” Jain explains. “It is not just the use of some of these materials, but making also adds heavily to the carbon footprint,” she adds.
Experts hold a unanimous view that scant, or a lack, of green cover also adds to the heat in urban spaces. “Our cities lack green pockets that can act as the lungs and keep temperature and air quality in the city under control. There is a need for a joint effort by the architects, urban planners, and government stakeholders to design more sustainable cities,” says Jain.
The way forward
Looking at the past could be a solution. “We know the issues with concrete. At the same time, our age-old timber sloping roofs with clay tiles can easily last for more than a century, especially with the modern know-how of science and technology,” says Kuriakose. “A simple tiled sloping roof not only provides water protection, but it is also excellent at quickly radiating heat off due to its low thermal mass compared to a concrete roof, and if designed properly with overhangs, it prevents the walls of the building from picking up heat,” he adds.
Along similar lines, Kadri says: “In India, we have extensively used lime and gypsum mortar for centuries, which is almost carbon neutral”. In their upcoming project in Kanha, his firm has proposed “rammed earth” as a building material. “It is environment-friendly, non-combustible, thermally insulated, sturdy, long-lasting, easy to build, and has a minimal carbon impact. Walls made of rammed earth can last for thousands of years,” he explains.
Jain, too, thinks that the solution has to be a composite one that must conflate the best from our past to the present. “It’s time we use our design thinking to reconsider old building techniques and reinvent them in today’s context,” she adds. The architect from Chennai gives the example of the city’s LIC building, built-in 1959, also the tallest in India at that time, “which stands relevant to today’s climatic context”. “The building skillfully uses a concrete skin facade to protect it from excessive heat gain, enabling a seamless ventilation system that is much needed to respond to Chennai’s hot and humid climate,” she explains.
So, is a mix of traditional and modern the way forward? “Innovation is the key to a better future,” says Jain. “At CAI, we are highly inspired by vernacular architecture and remold it by using today’s modern materials, without necessarily replicating them,” she says.
Kuriakose says the union of modern construction techniques with traditional ideas is what we have been trying to perfect over the years. “The wide regional variations within a state in India is something we must learn to appreciate, and learn from, and adapt to a modern context and our contemporary ways of life,” he adds.
Meanwhile, Dahiya thinks that rather than traditional vs modern, sustainable materials and techniques that are suitable for the local climate should be the way forward. “Research, innovation, recycled material, and technological advancements in building materials and construction for catering to climate change must be prioritised,” he adds.
Urban heat islands
- Heat islands are urban areas, which experience higher temperatures than those outside the cities
- They develop as buildings, roads and other infrastructure absorb and re-emit more heat than what trees, water bodies and other natural landscapes can do
- For example, the temperature can rise to 40°C despite it actually being 35°C
Glasses ideal for India’s climate
- Clear or clear float glass for shaded windows
- For commercial buildings, the specifications of glass need to be carefully chosen based on its heat absorption coefficient
CO2 emissions in cement production
- Cement industry contributes to 8% of India’s CO2 emissions
- It generated 576 kg CO2/tonne in 2018
- Green concrete is being experimented with. It uses eco-friendly waste materials and emits less carbon
- Strong and stable
- Cement production is extremely energy and fossil fuel intensive
- Low tensile strength