Diamond Exchange, Capital C Amsterdam, Amsterdam

The grandeur of a national monument fades

At the time, Amsterdam had grown into one of the world's leading centres of the international diamond industry. This was reflected in the distinctive design of the Diamond Exchange. It was modern and functional, with a strong rhythmic composition, yet also possessed classical grandeur, expressed through its distinctive clock tower and refined decorative details. This jewel of the city, with its restrained Art Nouveau style, was therefore designated a national monument.

By the beginning of the 21st century, however, the building had fallen into decline. After various additions, a fire and several renovations, little remained of the grandeur of the original monument. Its architectural character had been flattened and obscured by monotonous additions that concealed the qualities of the original design.

A new beginning, a new century

The new owners, Zadelhoff B.V. and Sijthoff Media, envisioned a new future for the Diamond Exchange, reflecting Amsterdam's emergence as an international centre for the creative industry and information technology. To fulfil this ambition as Capital C, the building required a comprehensive renovation. ZJA Architects & Engineers, in collaboration with HEYLIGERS architects, developed a design based on three key objectives: to restore the distinctive qualities of the Diamond Exchange to their full glory, to adapt the interior for modern, flexible office use, and to introduce a contemporary, publicly accessible space.

The restored Diamond Exchange meets the city

The largest addition consists of the restaurant and the terrace on the seventh floor, under an oblong dome. The construction on the roof is based on the grid shell principle, in which the constructive force is absorbed by the double curvature in the roof’s surface. That allows for an enormous freedom in shapes and a large span without columns. The dome’s structure, covered with glass panels is transparent, light and open. 

With this renovation the Diamond Exchange is to be restored to the original design by Van Arkel. That is paramount. The new dome echoes the dome of the bell tower, but with its multifaceted glitter also refers to the past of the building. The bell tower remains the landmark.

By raising the floor of the sixth storey, the dome appears even lighter and more detached. The rooftop structure stands independently, set back from the original façade line and separated from the domed tower.

From street level, the relationship is immediately clear: the restored Diamond Exchange takes centre stage, while the rooftop addition plays a supporting role. The new public space is a transparent and inviting gesture, reflecting light and sky in all directions.