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Roofing the Modern Mall

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In the last few years, the large-scale shopping malls have undergone a slow but steady rehabilitation in design circles. The view that malls are airless and claustrophobic has been progressively diluted by new projects that are introducing design innovation and subtle individuality.

The most difficult challenge presented by large footprint buildings such as malls is daylight ingress or the use of skylight. This seems simple enough given materials like multi walled polycarbonate and high performance glass which have come into the market, but unfortunately these still result in a heat build-up, especially at the higher floors and no one has proven the effects of expanding hot-pockets when the external surface temperatures touch 70 degrees.

An effective method is to use sun breakers on the outside. These act as a partial shield or transparent membrane which can reduce the heat coming into the space. There are many materials which can be used to create such a system, like architectural fabric, PTFE, steel, or glass itself. The advantages are innumerable but the biggest impact is a more engaging architectural surface which can be used to define a strong architectural vocabulary of the region.

Adding a third membrane to trap and exhaust the heat adds to the efficiency of the system, significantly reducing air-conditioning costs. This results in a more engaging, energy efficient architecture with long terms benefits. Our firm achieved similar efficiency with the Discovery Centre in Bangalore wherein the roof is an assemblage of Danpalon, Fabric & sunbreakers with a pressurized exhaust.

Transparent roofs aren’t the only source of heat, even opaque roofs, though they transmit heat slowly are a problem. Once the heat is trapped inside the space, cooling it will always be a problem. The solution is to minimize the ingress of the heat thus reducing loads for air conditioning and having a system in place to expend the trapped heat rather than trying to cool it.

Instead of simple insulated roofs or reverse roofs materials with high solar reflectance may be used especially on surfaces that are accessible for only maintenance. Another way to handle the heat is a Green roof which unlike the previous suggestion is accessible and has the potential of becoming a great urban space which is usable. An example of this is the California academy of science. This also helps in combating the urban heat island effect. Traditional building materials absorbs radiation and re-emit it as heat. Thus, the problem needs to be tackled at the building component level also. Architects today should pay close attention to detail to resolve these issues as energy consumption will only increase with the temperature changes in our cities.

“Some mandatory design principles for a successful mall are: provide natural light, reflect the heat out, make a large span structure and keep the structure light.”

– Akshat Bhatt
Principal Architect
Architecture Discipline

Revisiting the planning principles

Malls are laid out large footprint buildings, since most planners believe that shoppers will not travel more than four floors in a retail environment. This presents a few challenges.

The first challege is that of visual fatigue to the user. It is much like museum fatigue i.e. people need relief from the barrage of seductive imagery. Therefore, it is important to incorporate a break from commercial activity that will enhance the experience resulting in increased commercial turn around. This visual break also addresses the lack of visual interface with the surroundings in most malls and can add to the life and social relevance of the building.

Secondly, the present malls are usually inward looking with an anchor store, some entertainment areas and small stores which often feed-off the activity. Such mall spaces come with an expiry date. According to many surveys, the malls tend to thrive till the novelty factor doesn’t wear off. This results in a slow degeneration of the urban space that finally results in a dead mall which gets re-configured as small office spaces.

Given this cycle, it is important to reexamine the planning principles and construction strategies of these giant spaces of consumption. Can they be more relevant programs and given the number of people drawn to them, can these be engineered to demonstrate good development practices?

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