Step by Step

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

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

What appears to be the inside of a modern club or upmarket art gallery is actually home to a family with two children and a cat and is used just like any 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 lighting designer from Berlin, planned and installed the lighting engineering in this house, as well as built a staircase that is unparalleled in its design.

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 in a step-by-step approach. To start, 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 indestructible. A 6mm thick cover sheet of high-quality white glass was then laminated onto this. Upon closer inspection, this cover sheet is crystal clear and has no green tinge, unlike 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. Still, much more challenging 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 ACRYLITE® LED light guiding edge lit acrylic sheet 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 ACRYLITE® is a major advantage. The entire glass step was therefore backed with ACRYLITE® LED light guiding edge lit acrylic sheet.

Let there be light!

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 a touch panel. Another nine light scenes can be selected via smartphone.