© KNAUF / Design: Naveen Mehling

Step by step

Transparent, illuminated and unique: PLEXIGLAS® offers new design options for staircases too.

The first impression is decisive, also when you enter a house. In this one, everything has a rather futuristic touch. The façade is bright orange. The entrance hall has a dark wooden floor, with white and orange walls and pop art pictures. Glowing colors are reflected onto the walls by a transparent staircase.

What looks like the inside of a modern club or upmarket art gallery is home to a family with two children and a cat, and is used just like an ordinary residential building. It is situated in the hills above the Turkish city of Ankara and belongs to a German entrepreneur family that has settled there. Naveen Mehling, a light designer from Berlin, planned the lighting engineering in this house and also installed it – as well as building a staircase that is completely without parallel.

What is behind the design of a staircase featuring edge lighting?

Transparent stairs

“I would like an illuminated glass staircase,” said the client. Mehling set to work, well aware that this would be the first development of its kind. The demanding project was tackled step by step. First of all, a structural engineer made the necessary calculations. The first question to be answered was “How can you make a solid glass step sized 1,350 by 300 cm self-supporting?” The plan was for the steps to be supported only at their upper end. The result was that 19mm thick, partially pre-tensioned white glass was used for the individual steps. This was brought up to red heat (630 degrees) and then slowly cooled, giving it a very high surface tension and making it virtually indestruc-tible. A 6mm thick cover sheet of high-quality white glass was then laminated onto this. On closer inspection, this cover sheet is crystal-clear and has no green tinge like commercially available glass. Thousands of micro pits were then lasered into the surface. These act like suction cups and provide the glass with Class R9 slip resistance.

Mehling opted for LEDs to illuminate the stairs. It was easy to choose the right illuminant, but much more difficult to find the right material. “Glass is unsuitable for uniform lighting,” Mehling says – especially for the two large landings that measure 1.35 by 1.50 m and are built just like the stairs themselves. “I decided to use PLEXIGLAS® LED because it is the only material that ensures homogeneous lighting.” This material was specially developed for objects that are edge-lit with LEDs. “In the past, we tried to use only glass for such projects. But the light was not guided to the surface, and light spots were visible on the glass edge,” Mehling explains. The unimpeded light flux offered by PLEXIGLAS® is a major advantage. The entire glass step was therefore backed with PLEXIGLAS® LED.

Let there be light!

Glass is unsuitable for uniform lighting.

Naveen Mehling
Light designer from Berlin

To make the steps glow, 4,840 LEDs were distributed around the steps. The light cables are concealed in the load-bearing supporting members. “The challenge to be met with a lighting concept is to keep the technology out of sight,” Mehling says. The LED printed circuit boards were custom-built. “RGB-LEDs can produce the entire color spectrum – 16 million colors – by means of DMX lighting control,” he explains. This type of control means the color can be individually selected for each side of the steps. The computer uses pre-programmed light scenes that the house inhabitants can control via touch panel. Another nine light scenes can be selected via smart phone.

Mehling completed the project after six months of planning, design and implementation. This is just one of the many intriguing lighting concepts the designer has created using PLEXIGLAS® and LEDs. For example, he used this combination to turn a complete Currywurst stand into a tasty eye-catcher.