How sunshades work

Responsible building design practices, should promote its importance, says Anupama Mohanram

A sun shade or ‘brise-soleil’ (derived from the French word ‘sun breaker’), is an architectural feature of a building that reduces heat gain by deflecting sunlight. A history of providing shading from the sun is found in the early Greek and Roman buildings in the form of porticos and colonnades. Traditionally called the chajja in North India, it comprised large roof overhangs supported by carved brackets, primarily seen in traditional Rajasthan, Gujarat, Punjab and UP.

A sunshade in today’s context could refer to any horizontal or vertical component to protect the building from climatic elements. Apart from playing a pivotal role in reducing heat gain and preventing water ingress, the sunshade has also been a key feature in dictating the aesthetics of a building form.

Climate sensitive

However, today, looking at our contemporary steel and glass architecture which completely relies on air conditioning for heat control, the concept of sunshades seems to be losing ground. In our warm and humid climate of Chennai it would be unwise not to factor in sunshades into the design of buildings, air conditioned or not!

It is time to re-evaluate climate sensitive design, look into the past and ensure we bring back this important building component to prevent heat ingress, thereby reducing our energy needs. In a city like Chennai, sunshades also aid in diffusing natural harsh direct light and reducing glare.

There are myriad options available today that can be incorporated in aesthetically pleasing ways into building designs. Options such as horizontal shading including awnings, vertical shading including fins or louvres and a combination of any of these can be used considering the orientation of each façade.

Exploring materials

The most common material used for sunshades is RCC. However, alternate materials are being explored such as metal, wood, bamboo, glass and even fabric. Tensile structures are also gaining popularity as shading devices. Sunshades may also be motorised as awnings, drop down or angular rotation as per the building orientation and sun path. Retractable shading devices are also a possibility today. With the advent of BIPV (Building Integrated Photo Voltaics), solar panels can also be designed to function as sun shades.

Horizontal roof slab projections and vertical masonry wall extensions can also serve as sunshades that can be constructed as part of the main building structure.

Responsible building design practices, especially in the tropics, should promote the importance of the sunshade, irrespective of the building type, to make architecture more climate sensitive and site responsive, thus negating the effects of environmental damage due to buildings in whatever little way possible. The availability of multiple options also provides architects with the possibility of high level of innovation in aesthetics and sun control.

The author is

the founder of

Green Evolution, a sustainable architecture firm

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