Exclusive living surrounded by peace and quiet

Transformation of The Mayor nears completion

Former KPMG office complex 'De Bovenlanden' in Amstelveen is being transformed from a massive office building into a light, luxurious and comfortable residential building. The building will house 315 spacious apartments for sale and rent, including 39 penthouses and 10 park villas, in a green oasis of peace and space.

In the preparatory phase, building consortium UBA - de Nijs Amstelveen v.o.f. investigated the technical feasibility and manufacturability of the design. In addition, the construction combination was responsible for coordination between the structural engineer, W- and E-installers and other stakeholders. "We were on board very early on. Not only because of the enormous size of the building, but also because of its age," says Martin de Waal, project manager on behalf of UBA - de Nijs Amstelveen v.o.f. "The former office complex dates from 1986. Back then, the dimensions were a little less precise than today. In order to gain clear insight into the as-built construction, we had a 3D laser scan and point cloud made, which were then translated into the 3D model by ROOT. Based on this, the plans were slightly adjusted. We then disconnected all utilities and started the strip demolition." It was decided to carry out the transformation in three phases, he says, addressing 3, 4 and 2 blocks successively. "In August 2020, we started phase 1 (3 blocks). This phase was completed in the summer of 2022. Currently, we are busy with the completion of phase 2 (4 blocks) and the shell construction of phase 3 (2 blocks) is also almost complete. In the first quarter of 2024, the complete transformation will be delivered on schedule."

Interruption of the structural chain

During the major strip demolition, all inventory and the screeds in the building were removed, says Joeri Bakker, main contractor on behalf of UBA - de Nijs Amstelveen v.o.f. "In the process, additional temporary reinforcements were put in place, in the form of steel structures and additional concrete walls, to allow for the structural demolition as well. The buildings, which previously formed one continuous chain, were structurally disconnected and reconnected by means of footbridges and (additional) elevators. This ensures the accessibility of all the buildings, without sacrificing useful habitable area." De Waal: "Four steel elevator shafts were added in each block and large openings were cut for the balconies and sliding doors. A new steel structure was also added and the roof superstructures for the penthouses made, after which the temporary support was removed again."

Volume expansion with minimal weight gain

"The penthouse construction has been realized on the roof floor of the former office building," says Robin Mulders, Head of Work Preparation on behalf of UBA - de Nijs Amstelveen v.o.f. "To make this constructively possible, numerous provisions were made. Consider, for example, the addition of (additional) adhesive reinforcement and various structural components. Because the existing foundation allowed little additional structural load, light materials were chosen as much as possible for the construction of the penthouses." De Waal: "Weight saving is a common thread in this project. Our challenge is to always seek an optimal balance between structural possibilities, living comfort and appearance. A good example of this are the spacious balconies, based on concrete balcony slabs and with lightweight filling. Around the individual buildings a new facade construction will be applied with a thick EPS insulation and crab plaster finish, characterized by high-quality aesthetics and limited weight."

Sustainability in optima forma

The crab plaster has a base of natural raw materials and guarantees a characteristic and durable finish. "Sustainability is also reflected in the installation techniques," said De Waal. "All homes will soon be powered by a central CHP system and solar panels will be installed on the roofs." Mulders: "We have also found a demolisher who has carefully sorted all the materials coming out of the building for reuse in the circular economy. Very sustainable, moreover, is that we are giving an existing and obsolete building a high-quality second life with this repurposing." Bakker: "All homes will be finished to a high standard, including kitchen, bathroom and flooring. And we will also take up specific buyers' wishes, provided this fits within the technical possibilities of the building. This will create 315 unique homes in an oasis of greenery and at a strategic distance from the Stadshart shopping center, the Amsterdam Zuidas, Schiphol Airport and the A9 freeway, which will soon be deepened and partly covered by wide bridges with a park layout."