Smart cooperation between Xella and Van Wijnen yields substantial time savings in high-rise buildings

Creative solution shortens demolition time of Hague residential tower the Hoge Regentesse by months

Thanks to a clever collaboration between developing builder Van Wijnen, supplier Xella , Bestcon, Faber and various installers, the construction time of The Hague's De Hoge Regentesse residential tower has been significantly accelerated. Compared to a traditional finishing process, the 23 floors are estimated to be completed some three months earlier. The time gain is due to the very early pre-pouring of packages with Ytong cellular concrete inner walls, even before pouring the floor with foam concrete. This creative solution enables Van Wijnen to deliver one floor per week.

The Hoge Regentessse is a 23-story residential tower located just south of downtown The Hague. It is being realized on a very small building site. This requires the utmost in construction logistics. To minimize the burden on residents, traffic and businesses in the city center, Van Wijnen opted for a rapid shell construction system in which a centrally located crane installs precast concrete floor, wall and façade components.

Fast shell construction, fast completion

A way was also sought to speed up the completion process. Van Wijnen's aim was to deliver one floor per week. Xella was at the table with Van Wijnen for this at an early stage. In consultation with the installer, the parties found a special solution: prepping the packages with Ytong aerated concrete walls on Ytong blocks, even before pouring the foam concrete screed. "As a result, once the screed has cured and a first waterproofing layer has been applied on a higher floor, the setting of the walls can be started immediately," says business developer Bas Peereboom of Xella.

More efficient provisioning

Because aerated concrete is moisture-sensitive, the panels can be delivered as early as the structural phase. In addition to being able to start assembly immediately, this provides more advantages, explains Van Wijnen's chief executive Richard de Boer. "Because the packages of Ytong have already been brought in during the structural phase, there is no disruption from the construction elevator. We also don't have to bring the packages in with a stabbing elevator, which saves quite a bit of time." In addition, De Boer speaks of a "much more efficient supply." "The aerated concrete walls are delivered to size in stickered packages. Exactly what the wall erectors need is ready for each floor. That saves on transport movements and there is little or no waste."

Three months shorter phase-out period

Thus, unlike other interior wall systems, the panels are not transported upwards afterwards via a construction elevator. This minimizes the number of vertical and horizontal transport movements. It is estimated that prepping reduces the completion time by as much as three days per floor on average. 2

On the centimeter

The clever collaboration did require a complex puzzle in preparation, says Xella's Peereboom. "The challenge was to lay down the packages exactly as they were without tying up with the MV pipes and other installation work. Therefore, the packages of aerated concrete were set on Ytong blocks that are exactly the same height of the foam concrete screed to be poured. Once the floor was poured and cured, those aerated concrete blocks merged into the screed and the panels were ready to be set." The position of the blocks was matched exactly with the piping and included in the construction drawing. We even consulted with Bestcon, the manufacturer of the precast walls, about the position of the braces and outriggers, so that they too would not be in places where our packages needed to be."

The result of the joint effort is impressive: the construction time of the total project is reduced by approximately three months. In addition to the Xella material used, Van Wijnen also chose to have Xella Construction Services handle the assembly of the walls. This ensures both the quality of the material and the labor.

The High Regentesse will be completed in early 2021.

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