Their award-winning project, which wraps two office buildings inside a unifying and visually intriguing sheath of aluminium, is called "Clara and Robert" to honor the 19th-century composer Robert Schumann and his wife, Clara.

The building on the west along Johannstrasse is Clara, and the one to the east is Robert. Both are new, seven-story buildings built in L-shapes connected by their campus setting and underground parking. Above ground, they share the site space with the historic Saarhaus, which was an old barracks from the Wilhelminian era and something of an architectural oddity in its own right, the architect says.

"It was a simple entrance building to the sports and training hall without any outstanding or spectacular architecture," Slapa explained. Yet the project managers still wanted to keep the identity of the place.

So the romantically named office complex was built so that the aluminium exterior of Robert extends beyond the office walls and roofline, shielding their 130-year-old neighbor – and the residential tenants who now live there – with a clean outer skin that changes across the day as the light and shadow move.

More than 19,000 square meters are covered in PREFA cladding in polished aluminium, sized so that the composite panels are large enough to deliver the long lines and planned keyhole cutout effects. The vertical slits in the aluminium wrap are inspired by the perforated-metal discs used to record sound for mechanical musical instruments in the 19^th-century era of Schumann and the Saarhaus.

What's intriguing about this architectural symphony is that the end result neither dwarfs the Saarhaus, nor looks at all forced as if in some misguided attempt not to. From the street, the effect is both striking and soothing, with the aluminium extensions serving to create a rooftop terrace in the midst of the city.

It's from the inside, though, that it is easiest to see how the historic and modern neighbors stand shoulder to shoulder. The adjacent stairwell of Robert, with its clean monochromatic lines in black and white, and with all of its glass and aluminium shimmer, is framed on the inside wall by the yellow-red bricks that were the Saarhaus exterior, before it was wrapped in a layer of the office building merged within.

Clara gets some real attention too, as did the composer in her own right in real life. This office-complex partner building includes a four-story glass cube, with a cantilever construction. It extends from its aluminium shell with conference rooms and meeting spaces bathed in the exposure to natural light. From street level, the building extension appears like a tiered atrium with an open-air balcony on its roof – a cube that pedestrians walk beneath, because its extension mirrors that of Robert's protective cladding and construction hovering over the Saarhaus.

In addition to the sustainability benefits of aluminium construction, Robert and Clara are equipped with solar protection and thermal insulated glazing at the windows, the specific structure and thickness of which were modified for need depending on the side, height and other conditions of their placement.