From full-page newspaper advertisements to huge hoardings along city roads, grand visions of high-rise apartments are popping out, enticing us to buy one today itself. Additionally, the catchy slogans like 75% garden, only 25% built and such others make us think as if we are going to live amidst green, though in reality we could be living in a crowded high-rise concrete tower with no green right outside our house.
The assured green could be in one large parcel at one part of the master plan, with no benefit to every living room of an apartment in the complex. Are these high-rise residential blocks really eco-friendly as they may claim? How do low-rise houses compare with high-rise single blocks?
Many such complexes have got green building certifications, but they are not based on embodied energy or options for low energy designs; instead they are based on the criteria laid out by the certifying agency.
Major differenceFor the developer, utilising the maximum permitted built area called floor area ratio (FAR) is important for return of investment, so he would utilise the FAR equally, high-rise or low-rise. The major difference would be in the ground coverage, where the option of tall tower block would leave more ground area unbuilt, claiming it to be garden – a unique selling point.
YardstickIn the architects’ professional circles, comparison between low-rise high density development and high-rise high density development has been an age old debate, with both the theories attracting their supporters.
However, if energy consumption and sustainability becomes the yardstick, high-rise apartments tend to raise more questions. They demand on site management, mass concreting, precise execution and an efficient supply chain to ensure smoother project completion. To that end, hi-tech practices, multiple high speed elevators and such others are a must both during and after construction with uninterrupted power.
Due to the extra efforts required in lifting materials and moving people to higher levels, labour costs increase with building height.
Maintaining the wall surfaces of tall buildings is a challenge, so the designers tend to opt for materials such as aluminium and glass, known for high cost and high embodied energy, besides many other manufactured materials.
If the walls are largely plastered and painted surfaces, their periodic repainting can be a humongous task, at great cost. Higher we go lesser we get to see the ground-level gardens and lesser accessibility to them, actually an anti-thesis to the selling point, whereas in low-rise apartments, there could be a visible open area outside each unit.
In a multi-level apartment, construction is sequential with each slab casting, but in a cluster of low-rise houses, it can be parallel, saving project time.
Many occupants of tall residential concrete towers complain about them being large and intimidating, while smaller group of houses can form social spaces and human scale – possibly a reason stronger than that of eco, to critically relook at high-rise houses.
(The writer is an architect working for eco-friendly designs and can be contacted at varanashi@gmail.com)
