Walk into almost any mall built in the last ten years and look up: steel lattice, glass panels and daylight falling into the atrium. It is a trend with a simple reason behind it.
Daylight cuts the cost of lighting a huge interior space, and studies of shopping centres suggest people linger longer in daylit areas. In a hot climate the trick is letting light in without the heat, which is why the panels are fritted, tinted or shaded.
What to look for
Notice how the roofs are divided: triangles spread load in curved roofs, squares suit flat ones. Notice the shading too; the best roofs feel bright without feeling hot.
The trade-offs
Glass roofs are not free. They need cleaning, they can leak where panels meet, and without good shading they can turn an atrium into a greenhouse by early afternoon. The best ones use fritted glass, external louvres or both.
Architects also use them to make huge buildings easier to understand: a bright central space is a natural place to meet, and it helps people find their way back to the entrance.
Next time you are in one, look at how the light falls at noon. If you can stand in it comfortably, someone did the maths right.
A brief history
Covered shopping arcades with glass roofs appeared in European cities in the nineteenth century, when iron and glass made large spans possible. Manila’s older malls mostly closed themselves off with solid roofs and air-conditioning.
The return of daylight is partly about cost and partly about mood. People walking under natural light spend longer, sit down more often and come back. Developers have noticed, and so have the cafés that cluster under the brightest skylights.
The next generation of malls is trying open-air courtyards with planted shade, which may turn out to be more comfortable than glass.
The next time you are waiting for a friend in an atrium, it is a better view than your phone.
