Future proof with historical grandeur

On Lange Voorhout, one of The Hague's most beautiful avenues, the Bentinck House has been transformed into one of the city's most prominent office buildings. We look back on a large-scale renovation project in which respect for authentic grandeur and the highest sustainability ambitions go together perfectly.

The Bentinck House is owned by listed office investor NSI, which bought the property in 2018. "The Bentinck House has a rich history," says Asset Manager Annemarie de Leuw of NSI. "In 1754, the Bentinck family occupied the property as a residence. The State of the Netherlands became the owner of the property in 1819. The Ministry of Marine and The Supreme Court took up residence there, among others." In 1996, the monumental building was expanded with the so-called new building section: an extension with a courtyard garden and atrium.

Future proof

"The Bentinck House fits into our vision of future-proof buildings," De Leuw continued. "With this renovation, we are preserving a special, monumental building for the future. Future proof means that the building is sustainable and innovative, and offers optimal user comfort. Among other things, we are applying thermal energy storage, solar panels and a sedum roof. Smart sensors for temperature, CO₂ and presence control the installations automatically, thus contributing to a substantial energy reduction. The installations can also be managed and monitored by the user per room, via a control panel or an app. And through smart data use, the rooms can be used optimally." For optimal user comfort, among other things, 42% additional window area has been added in the new building section, bringing in much more daylight.

Good preparation

In a construction team context, design and execution method were prepared in detail. The time and attention paid to this in the preliminary phase paid off in a smooth construction process and contributes to the high level of comfort and efficiency for the users. "At the end of 2018, we were selected for the construction team to think along from our expertise in large-scale renovations," explains Managing Director René Middelkoop of Du Prie construction & development. "The impressive wokkel staircase in the atrium was a big focus. This staircase covers five floors and has a considerable diameter. Fitting and placing the staircase required a lot of measuring and calculation. Together with design staircase specialist EeStairs, we worked out the staircase completely in 3D."

High end furnishing

The transparent atrium and wokkel staircase add grandeur to the Bentinck House. Including a coffee bar and courtyard garden, the atrium also serves as a meeting place for the building's users. The office floors are accessible via the staircase. De Leuw: "We opted for a high-end interior with a lot of glass and wood. For this, the new building section, consisting of five floors and a basement, was completely stripped and rebuilt. The four-story monumental part was renovated, with respect for the historical elements, and equipped with modern technologies."

Five-meter-high curtain wall

After the 2019 construction period, Du Prie started the demolition work. "Especially the old steel staircase and the thick concrete floors took some effort," says Middelkoop. "After the demolition work, we enlarged the facade openings and installed the new window frames. Then we rebuilt building sections. On the office floors, we installed new installations, walls and ceilings, among other things. At the rear of the building, we renovated the entrance with a five-meter-high curtain wall."

The power of a construction team

Implementation was primarily a logistical challenge. Because of its historical significance, Lange Voorhout had to remain clear as much as possible. Transportation took place via the rear, a one-way street, and had to be scheduled well in advance. De Leuw: "At the same time, we demanded the necessary flexibility from the construction team. During execution, we brought in additional ideas, to even better fulfill our ambitions." Middelkoop: "That's where the strength of a construction team lies. Together we looked at what was possible and we fleshed it out." De Leuw: "Good discussions took place. That benefited the quality. The Bentinck House has become a fantastic office building that can last for many years again."