The example of sustainable construction emerges in Driebergen. Triodos Bank and project developer EDGE Technologies (formerly OVG Real Estate) commissioned the construction of a new office for Triodos Bank at Landgoed De Reehorst. With the new office, Triodos Bank and EDGE set the bar extremely high in terms of sustainability and quality. The unique glass facade is the eye-catcher of the project and the use of multiple materials makes it a challenging project. Octatube was chosen as an experienced facade specialist by general contractor J.P. van Eesteren to build this sustainable facade.
The building consists of three towers of two, three and five floors with a unique sustainable wooden construction, covered with green roofs and enclosed by a fully glazed facade consisting of 1,280 glass panels (on average a panel weighs about 200 kg).
Sander Persoon, project organiser at J.P. van Eesteren: "Because we build with a combination of a wooden construction and steel façade elements, dimensions are extremely important and complex. Fortunately, as J.P. van Eesteren, we are working closely with Octatube on this project. After all, in innovative projects like this, you certainly run into problems. And you want to solve them together."
Sustainability architect Thomas Rau designed the transparent facade to have an optimal view of the building and the surrounding nature.
Corine Dikkers, project leader from Octatube: "This transparency is achieved by working with glass panels, which are so strong that they can make a large span without a frame. For maximum insulation value and in order to achieve the sustainability ambition, the triple glass panels - for maximum transparency - for the most part, have no rear construction. The glass is placed directly on the steel structure."
This is a self-supporting glass facade that connects to the wooden floor construction via a steel construction. Octatube and J.P. van Eesteren, therefore, worked closely together in the engineering phase.
Corine: "Glass is a rare element in the appearance of this project. It soon became clear that the British glass division of Guardian Industries, a specialist in large-format float base glass, would supply the glass panels. They supplied the 6x3 metre panels. But then there are still many choices to be made in order to achieve an optimum in terms of sun protection, transparency and aesthetics. Fortunately, we were able to take a reasonably long time to use samples to include the architect and client in the various selection options, so that we could ultimately make a choice based on realistic examples. These choices were captured in a life-size mockup with 99% of the details. This gives a really good picture of the performance of the glass in all areas."
BREEAM is the tool to measure and assess the sustainability of new buildings, existing buildings, areas and demolition projects. With its wooden construction (PEFC-approved wood), green roofs, thermal insulation installation, high insulation value (RC value is 6) and 3,300 m2 of solar panels on the covered parking spaces, the building achieves the highest BREEAM-NL certification: Outstanding.
Sander: "The facade plays an important role here thanks to the triple glazing, the glass coating, but also the logistical process surrounding it. The steel frames of the steel builder, with the aluminium extrusion profiles pre-assembled by Octatube, are delivered just-in-time on an exchange trailer from the factory in Ede, where the prefabrication takes place."
But in addition to assembly, disassembly of the various parts of the building is just as important. Already in the design, it was taken into account that almost the entire building has to be disassembled in time. All parts and materials are registered in a Madaster material passport so that they can always be identified for reuse.
Corine: "In the case of glass, not only is it recorded where the glass panels come from; it goes much further. The glass can be traced back to the silicate, from which it is recorded where it was extracted. And we take into account the fact that glass itself will remain good over time, but that the amount of argon gas in the insulation panel will decrease over the years, which will also result in a slightly lower insulation value. When the time comes for this building, in this form, to be at the end of its life cycle, the glass can be applied to a project where the insulation value is perhaps less critical. It would be nice if the windows could be given a second or perhaps even a third life. It's a good thing that the material passport ensures that the materials and their characteristics are well defined."
Triodos Bank, Octatube and EDGE Technologies are working together to find a way to make the façade circular. One of the possibilities is to sell the facade to a consortium of Triodos Bank and Octatube. Whatever the outcome, Triodos Bank has challenged all parties to build the most sustainable building and to think very consciously about all parts of the project.
The building has been designed by RAU architects in such a way that the building and the surrounding nature form a harmonious whole. The building forms an inspiring environment for the employees and visitors of the building and estate. Throughout the building, the transparent facades offer employees and visitors a comfortable place and a view of the surrounding estate. This office promises to be sustainable as well as a very pleasant place. In short, an example of sustainability and quality in construction!