What is the most perfect material for a skylight? Find out more on the subject from green architect Sathya Prakash Varanashi

Let us walk into a designer home with skylights spread across the space. The light pouring down from roof, highlighting every object and creating shadows underneath, creates an interior design of its own, without using any costly gadget!

It does not take long to realise that the beauty of skylight lies not only in the light it filters in, but also in the manner the skylight itself is built.

What is the most perfect material for skylight? Well, there is none. Each option comes with its own baggage of problems and potentials. As such, our specific choice depends upon what do we intend to get out of the skylight.

Light of course, yes; but should it be clear direct light or indirect and translucent light? How much of rain, moon and sky we would love to look at? Is the skylight a practical application or also an image of the house?

The best of the lot

Clear glass, fibreglass, acrylic sheets, polycarbonate, multiwall section, glass bricks, Mangalore tiles with glass and perforated or jaali roofs have been attempted in the recent past. Clear glass, about 10 mm thick, is by far the best.

It best exposes the sky and moon; does not make sound under rains and the quantity of light can be controlled by shading sunscreen films. As variations of this idea, tinted glass also can be used. We need to ensure that direct sunlight does not fall on artistic paintings, delicate wood work or the morning newspaper that could be irritating!

On the flip side, the junctions need technically handled silicone joints. Glass may break if not well handled.

Performance

How do plastic-based sheets perform? They are easy to use, but perform rather badly compared to glass. Most plastics like fibreglass tend to look flimsy, appear dirty over the years and go brittle with age.

Polycarbonate sheets are better on some scores, but tend to get scratches easily. Though they both can be treated for ultraviolet rays, they tend to let in more heat, make loud sound under rain and fade in colour to show off their age within a few years.

Multiwall sections are two layers of polycarbonates sheets with air gap in between, which reduce heat gain, but are very costly.

Glass bricks or blocks are also in practice, though they are costly and provide only translucent light. If not well fixed, the joints between glass bricks can be a source of leakage over the years.

Mangalore tiles with glass piece within can be tried if we seek a traditional feel, merged with modern skylight! Tile dealers may not routinely keep such glass tiles, hence need to order separately.

Those seeking creative looks may try perforated roofs as skylights. Hollow sections, empty glass bottles or jaali blocks are embedded within the roof or placed after the roof is cast.

A piece of glass on top stops rain. It is the easiest way to create an array of sun beams dancing across the house as the day drifts.

(The writer is an architect working for eco-friendly designs and can be contacted at varanashi@gmail.com)

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