night mumbai lightsEven as real estate markets in most of the United States are still in the early stages of recuperating from the throes of the recession, there are still developing countries that are riding an economic wave of a real estate boom. These changing cities bring an opportunity to explore how the density of the urban environment can adapt and evolve to different environmental resources and climatic restraints around the world—what some designers would see as an inherent recipe for variability and evolution. The problem is that all too often these new versions of urban space are merely copies of western norms, lacking the site-specificity needed to link them to their surroundings. 

I recently had an Intercon reader write and request some conversation about vertical building solutions that might be more environmentally responsible than what developers are choosing to build as part of real estate booms in developing cities. Given that the reader was a native of India, Mumbai seemed like a good case study to use as an example. In cities like Mumbai we can see the rise of new development as derivations of popular Western buildings supplanted from the American and European archetype of tall, glassy towers that may not be equipped to consume and manage resources efficiently in their  local climates.

As economic growth puts more capital in the hands of a population, real estate can become an obvious choice for long term investment, boosting regional demand for new buildings. A market-based response could be to maximize profit opportunities, pushing developers or investment agencies to build new space as quickly and affordably as possible to pass it into the hands of eagerly waiting buyers. The mechanics of the marketplace are relatively simple, but the sustainability of the model rests largely in how cheap and how fast the new built environment is being realized. The environmental attributes of Mumbai bring unique complexities and challenges for siting new concentrations of people and services. If sustainability is a goal then the next evolution of  cities like this one should be producing a new genus of built environment with site-specific considerations rather than traditional models of existing cities transplanted into completely different environments with hopes for the best.

The Rise of Mumbai

For over a century, Mumbai has been the destination of a rural-to-urban migration with the rate of growth  steadily increasing into the present. With over 20.5 million residents in the metro area, Mumbai is the most populous city in India and the fourth largest in the world. At the same time, it is estimated that 50-60% of the city lives in slums, suggesting that the boom in real estate is more of a focused market event that creates a temporary influx of capital to a limited class rather than more broadly raising the standard of living to the population at large.

In growing cities like Mumbai, the perceived demand for new floor area calls for new towers. The market, in its quest for a solution high in speed and low in price, often chooses curtain wall. Popular through many parts of the world for tower construction, “curtain wall” refers to panelized exterior wall systems that link together as they hang outside of a super structure (like a curtain). The wall panels can be manufactured off site while the structure is built and then maneuvered to be installed by a handful of workers from the inside of the building. The result is a fast, cost-effective solution to end up with a kit of parts for a tower’s exterior.

seagrams building NYC

Mies’ Seagrams Building

Though not inherently necessary to the system, curtain wall has a tendency to incorporate glass panels instead of a solid option with greater insulating values. The practice is not one restricted to only developing cities like Mumbai. Ever since Mies Van de Rohe wrapped the Seagrams Building on Park Avenue–often regarded as the birth of modern curtain wall buildings–designers in cities across the globe remain drawn to glass buildings, despite their environmental shortcomings and higher material costs. The Midcentury Modern paper by Terrapin Bright Green highlights the energy-related drawbacks of using only glass to wrap a superstructure. However, as new taller buildings are leaning towards providing real estate for affluent clients, the current industry perspective lends higher sale prices to larger views.

Maybe so, but are people paying for view or are they paying for a perceived value that someone else may have on more open glass? The Urban Green Council recently published the results of a study entitled “Seduced by The View” where it looked at all glass buildings and how much of that fancy view is actually used. Interestingly enough, the study of buildings in New York found that 59% of glazed area was usually covered with shades or blinds and more than 75% of all glass buildings had more than half of their window views covered by subsequent development. The organization puts it well in saying:

“All-glass facades are a long-term problem. Twenty, thirty, or even fifty years from now, when the equipment in the building is more efficient due to replacements, the same glass windows will be there, putting a hard limit on how much the building can improve its resiliency and sustainability.”

Terahni India Tower

The importance placed on schedule and speed bleeds through the designs of each new tower as it rises. Built in systems and forms all too familiar to cities halfway across the world,  these projects are designed without an adequate study of what a skyscraper in these new environments “could” or “should” be. These kinds of misguided aspirations make so many sustainability initiatives impossible even before the project has begun. New Delhi should not be striving to become the image of India’s Boston or New York City because it will never be. Dubai will never be London any more than either will ever be Rio de Jinero, but a better question might be: would we really want them to be? What is the reason for promoting a global homogeneous development goal that is blind to the variety of history and cultures around the world?
The serge of development dollars has lead to the rise of towers like Hadi Teherani’s glass spire at Altamount Road. The all 30 stories of the luxury residential tower are wrapped in glass curtain wall–tinted glass, but glass nonetheless. Little about this design seems to be responding to its locale, but instead could be sited at any number of urban centers around the world. How will these new towers response to climate pressures and what kind of “city” will this series of seemingly autonomous buildings create over time?

As we have seen before in places like Dubai, a practice that may start as the inappropriate can quickly slide into the ridiculous. A prime example is the design for the Aquaria Grande by James Law Cybertecture International. The building starts off as a 30-story, undulating glass tower, but the real testament to sustainability is undoubtedly the balcony pools enclosed in glass railings. This is one of those things that begs a response of: “Really?” Putting aside the aside the issues of constructability and basic design sense, the amount of energy to build, maintain and undoubtedly repair this kind of an amenity is difficult to wrap one’s mind around. Stacked, high rise, balcony pools in a city that faces shortages of clean, drinkable water. Again… “Really?”

glass balcony cybertecture

The modus operandi of Mr. Law has a tendency to dwell in the theoretical realm of flashy renderings, postulating a next generation of architecture to “innovate the fabric of mankind”, so the odds are low that we will see these balcony pools any time soon. On the other hand, is this really the kind of architecture that should define our next generation of the developing world? The fact that these proposals circulate around to the groups of people that would love to see it realized is needlessly tempting fate to deliver kind of excess that flies in the face of both the needs and restrictions of its surrounding environment.

So What is a Climate-Responsive Tower?

A heat-conscious exterior skin is unsurprisingly most likely not made entirely of glass. Even an argon-filled, triple-glazed window (certainly not the norm) with two layers of Low-e coating only carries an insulating value of R-6.5 (the equivalent of less than two inches of spray foam or fiberglass batt insulation) and performs rather poorly in holding or rejecting heat. Though not providing the coveted floor-to-ceiling view, walls with more solid composition are a clear way to take on less heat and bleed out less tempered air that has already been cooled. For exterior surfaces, lighter reflective colors are an easy choice for reducing heat gain.

When in doubt, it helps to glance at local, traditional architecture for climatic building solutions that have been around for a while. Masonry materials like terra cotta or pre-cast concrete panels excel at mitigating the transfer of heat, making it no surprise that traditional buildings in the region gravitate towards the use of laterite, native clay-heavy soils that can easily be cut into bricks. However, newer, taller buildings veer away from generations of trial and error in towards glass and steel.

warm climate wall section sketch

Though it can be contrary to the practice of value-engineering, depth can be an ally for an elevation trying to reduce a building’s energy load and raise the quality of space behind it. When the material is held away in the form of a rain screen air can move on both sides of exterior panels, allowing them to cool off faster while preventing thermal bridging into the building structure (and the space within it). Adding elements that provide integrated shading at window openings can block the bulk of direct sunlight heating a space while serving as a light shelf to bounce indirect illumination against the ceiling. Speaking of ceilings, how tall do they really need to be? A 9′-0″ clear ceiling is quite generous, but more and more we see projects that can push apartments to upwards of 11′-0″, creating an extra 2′-0″ that is largely unusable but still needs to be tempered.

Green spaces, or sky gardens, are another great tool for creating exterior courts high off the ground. Whether they are occupiable or not, recesses in the building skin can preserve the real estate value of views while removing the energy cost of heat gain. Plants excel at being productive with sunlight and they bring the added benefit of soaking up storm water and cleaning the air.

Despite how much water the region gets, the city of Mumbai still suffers from shortages in potable water for its citizens. Given the wealth of rainwater that can be harvested during parts of the year, why would potable water be used for anything that does not absolutely require it? Like COOKFOX’s One Bryant Park, cisterns could be placed throughout a building in order to help provide gravity-fed water supplies for things like toilets or cooling towers. In the monsoon months, on site water treatment could help use rainwater for potable purposes to further depress the demand the building puts on urban infrastructure.

england heron towerDesigned by KPF, the Heron Tower in London is another example of designers taking steps to reprogram some of the “givens” of high-rise design for a more sustainable result. Years ago, I remember talking with Chris Stoddard, a project manager of the firm at the time, about the thought process behind the building.

As expected for a BREEAM-rated building, there are plenty of environmental accoutrements including LED lighting and an ice-storage facility for cooling, but one of the biggest design moves was to take the elevator core–usually located in the center of a floor plate–and push it to the southern face before covering it with PV panels. Not only did this allow service spaces to be lit naturally during the day, but it helped minimize solar heat gain into the office space by shielding it from its southern exposure. The offset core also allowed for a structural model of flexible floor plates that facilitated the combination of floors with atria into “villages”, each with its own HVAC system that can be changed out over time as technology improves. While the exterior wall is glass, it also happens to be triple-glazed with automatic shading devices.

New Cuffe Parade

WOHA Mumbai Green Tower

Courtesy of WOHA

Climate-responsive design is a goal seen throughout the work of Australian-based firm WOHA and their complex of planned towers in Mumbai is no different. Currently under construction,  the master plan calls for ten high-rise residential buildings plus one commercial tower, all configured around a massive 15-acre greenspace (65% of its 23 acre site). Lodha Developers is responsible for the project, planning to invest RS 10,000 crore (over $2 Billlion USD) in the site over 5 to 7 years, making it one of the largest development projects in the city.

The tower themselves are clad in perforated aluminum screens that shade the building behind from the full force of the sun. The integration of greenery on every floor, characteristic of many of the firm’s designs, not only helps to reduce heat load and mitigate stormwater runoff, but creates fantastic public spaces high off the ground–fighting the assumption that tall buildings need to remove their occupants from nature. In plan, the units are not bunched together around a common core, but split apart and connected by open-air corridors that allow air to wind through every floor of the building. As a result, the more spaces in the building can be air-cooled, drastically reducing the building’s energy load.


Courtesy of WOHA

Regardless of whatever systems are incorporated into the building like energy efficient lighting or low-flow plumbing fixtures, the designers have done more to manage the building’s energy load in massing and orientation than any of the efforts resting on technology alone in nearby buildings designed by their peers. Success in this arena needs a design process fundamentally detached from an exercise in maximizing zoning envelope and arranging square footage.

To be fair, even these new digs are not built for raising the standard of living for throngs of locals. The developer points to the arrangement of amenities–including pools, spas, fine dining and playing courts–as part of the catalyst to make the site a global destination. While its ecological footprint may be a fraction of other projects its size, New Cuffe Parade is not tackling the problems associated with swift gentrification and a broader wealth gap in large cities.

New Cuffe Rendering

Courtesy of WOHA

Quick Plans With Lasting Repercussions

The broader economic benefit of these overnight metropolises is most likely debatable. Only time will tell whether or not the new levels of construction help bring stable jobs to a higher percentage of the population or merely just provide a temporary side-effect of what will otherwise only encourage a more drastic divergence between wealth extremes. Either way, the economic attractiveness resulting from a global real estate interest will ultimately make it more difficult for the developing world to remain aware of its largest challenge: how to grow without repeating the mistakes of First World examples to the west.

There are countless, daily examples of American cities struggling to coordinate change into an urban landscape that has existed for decades, if not centuries. The evolution of existing infrastructural networks can be time-consuming and prohibitively expensive at a time when a more sustainable society all but demands rethinking how our cities function.

This presents the developing world with a unique opportunity. In many cases, the lack of vertical density and entrenched infrastructure in younger, smaller cities can serve as a benefit, allowing them a broader array of feasible options for sculpting a new, modern urban environment. The role of the urban grid can be reimagined. The public interaction with infrastructure can be reassessed. The relationship between urban development and natural features can be reworked.

These growing also have a litany of precedents for how other global cities have evolved over time and access to updated technologies in building and infrastructural systems that we never had to improve the quality of an urban center. A great cache of tools, but will they use it? So far, many of the latest examples show a preference towards building faster than building better; a hunger for today’s gross domestic product rather than tomorrow’s economic and social resiliency. The world could end up with more environmentally negligent cities that need to be “fixed” in places that have even less money to fix them after the hunger for square footage has been filled but appetite for distributed  market resiliency has not.

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Filed under: Green Buildings, Urban Planning Tagged: architecture, environment, mumbai, new, real estate, sustainabiliity