The new bank building also respects the flight paths of bats

The new administrative building of Triodos Bank in the Netherlands with a wooden structure features a striking undulating glass aluminum façade (Schüco), which is much more than just a feast for the eyes. The building is energy neutral, the materials used are documented in a digital material passport, and the structure can be fully dismantled and rebuilt. Thus, the Triodos Bank building sets global standards in the field of circular economy.

It is well known that construction does not lead to greater biodiversity or the creation of new natural habitats for wildlife. When excavators arrive, plants and animals have to relocate. Especially in densely populated Netherlands, there is a fierce battle for land, and effective protection of the climate, nature, soil, and water is very challenging. That these aspects can be reconciled is demonstrated by the administrative building of Triodos Bank completed in the fall of 2019 on the De Reehorst site in Driebergen-Rijsenburg, approximately 45 km from Amsterdam. The construction and design of the new building covering an area of 13,000 m² are based on the principles of nature and biomimicry, mimicking natural life. The complex consists of three interconnected towers with three, four, and five floors, and its organic shapes, materials, and natural colors blend with the landscape. At the end of its life cycle, its carbon footprint will be minimal. If the building needs to be dismantled and rebuilt, it is possible.

A new building as part of the ecosystem, not a foreign object fallen from the sky

The process of constructing this architectural masterpiece was as challenging as its unusual concept. Integrating the new structure into the landscape required significant planning to ensure that it would act as a part of the ecosystem and not as a foreign object fallen from the sky. The project also required a bold client with a vision, but at the same time, with the patience of a saint. Triodos Bank had both. The effort to find a suitable office building near Utrecht and Amersfoort that could accommodate the growing number of employees proved futile. In 2011, the decision was made to construct a new administrative building on the De Reehorst site. The choice of location was by no means a virtue of necessity - it was here that the Dutch bank was founded in 1980. It was crucial for the building to have a positive impact on people, nature, and the environment. After all, this sustainable bank operates in 43 countries and had assets exceeding 20 billion euros in 2020, investing only in projects with social, ecological, and cultural added value. Therefore, this philosophy had to be reflected in the new building. Ideally, a building should arise that would far exceed existing sustainability parameters and stimulate circular construction.

The architect perceives buildings as a "limited edition"

Thomas Rau, a pioneer of the circular economy and multiple award-winning architect, was perfectly suited for this project. In 1999 and 2006, he designed two headquarters for Triodos Bank. Internationally, Rau is regarded as a pioneer of circular, climate-positive, and innovative buildings, known for challenging the status quo and always seeking better solutions. He perceives buildings as a "limited edition," a combination of materials, products, and components that are time-limited and have a documented identity. In 2017, he founded the Madaster Foundation and launched an online platform of the same name for creating digital material passports for buildings. In addition to RAU Architects, the project involved the development company EDGE Technologies, construction company J.P. van Eesteren, interior design company Ex Interiors, and many other parties.

The project considered deer, badgers, and foxes

To sensitively integrate the building into the 30-hectare protected area, landscape architects from Arcadis collaborated with construction specialists from Copijn to create a concept that would enhance the quality of the space developed over many years. Water sources were added for deer, badgers, and foxes, and new pathways and greenery created additional hiding places. With the flight paths of bats in mind, the landscape architects and construction designers agreed that the height of the buildings should not exceed the height of the trees. They also agreed on using a green roof, which is friendly to insects and provides additional insulation and cooling effects.

The façade as a distinctive feature and stabilizing element

Visionary Rau lent the building a grand character through the use of amorphous curves in the structure, featuring a fully glazed aluminum façade. The stunning design was created using a special Schüco construction based on the window system AWS 75 BS.HI+. The highly thermally insulated block window with a basic depth of 75 mm features extremely slender external frame profiles without visible contours of the window sashes. The system boasts U_f values between 1.5 and 2.0 W/(m²K) and meets the most stringent requirements in terms of energy efficiency and architecture while offering maximum transparency. The chosen finish perfectly emphasizes the light character of high-quality aluminum window structures. Additionally, aluminum has several other unparalleled advantages: durability, stability, strength, and 100% recyclability.

The design of the façade took on an important stabilizing function by supporting the load-bearing wooden elements. The steel-based substructure certified for passive houses Schüco AOC 50 ST (Steel) with a width of 50 mm impressed both technically and aesthetically with excellent utility properties that combine energy-efficient construction, simplified manufacturing, and reliable assembly. The new insulating principle enabled the construction of a highly thermally insulated vertical façade with a U_f value of up to 0.8 W/(m²K). Large glass sizes with triple glazing were possible due to an innovative patented screw guide, allowing for a fill thickness of up to 63 mm and a maximum weight of 1500 kg. The seal elements without the use of sealant in the vertical façade proved crucial for achieving a professional finish. The use of powder-coated fasteners for the steel foundation structures, approved by the building authority, also allowed for reduced production time compared to welding.

A feeling of space like in a cathedral

Inside, the natural authenticity of the materials is absolutely stunning. The extremely high ceilings, wooden beams arranged in a mushroom shape surrounding the core, and consistent use of wood for floors, ceilings, columns, and shafts create a feeling of space as if you were in a "cathedral made of wood." The building with its fully glass aluminum façade composed of 1280 individual panes allows for maximum use of natural light deep into the space. Transparent partition walls, which also help reduce noise, provide a perfect view of the landscape almost from every one of the thousand workstations. The floor-to-ceiling windows in 3.60-meter high façade modules are practical as they can be opened, allowing for natural ventilation. Visual connections between floors are created by galleries accessed via spiral staircases. Short distances encourage occasional changes of workspace or meetings with colleagues over coffee at the espresso bar on the first floor. A total of 1615 cubic meters of glued laminated timber, 1008 cubic meters of cross-laminated timber, and five whole tree trunks were used for the construction, which received an "excellent" rating in the BREEAM sustainability ranking. The total of 2623 cubic meters of wood absorbed more than 1.6 million kilograms of carbon and will regrow in less than 12 minutes. Instead of conventional fasteners that would prevent dismantling and reconstruction, the structure is held together by 165,312 wooden screws ranging from 240 to 500 mm in length.

Parked electric cars are integrated into the energy concept

Since the façade could not be utilized for energy production through photovoltaic panels and the roof area was designated as a refuge for insects, the designers had to come up with an alternative location for placing more than 3000 m² of photovoltaic modules, which will generate 506,000 kilowatt-hours of solar energy annually to support the energy-neutral operation of the building. Why not use the roof of the carport and integrate the parked electric cars into the building's energy concept as an active energy reservoir through bidirectional charging stations? This idea became a reality thanks to the innovative project "We drive solar," which promotes cutting-edge solutions for mobility and energy systems under the EU research funding program "Horizon Europe."

A material bank for the future

By creating a material passport based on BIM that contains information about the origin and recyclability of all materials, products, and components for easy reuse in the future, the project partners ventured into uncharted territory. The planning process did not proceed as usual by individual professions but rather through integrated collaboration. As everyone perceived the construction project as a learning process and focused on teamwork, they quickly mastered the process. The biggest challenge was obtaining IFC files (Industry Foundation Classes, an open file format used by Building Information Modeling programs) from suppliers, manufacturers, and subcontractors in the required quality. The material values will in the future be tracked by the aforementioned platform Madaster. Therefore, the building is not just a repository of material but also a material bank, the value of which can be used, for example, as a long-term asset or capitalized elsewhere.

Project details

Project: Triodos Bank, administrative building
Location: Driebergen-Rijsenburg
Country: Netherlands
Design/construction period: 2011-2017
Gross floor area: 12,693 m²
Client: Triodos Bank, Driebergen (Rijsenburg, Netherlands)
Architect: RAU Architects, Amsterdam
Interior design: Ex Interiors BV, Nieuwegein
Landscape architects: Arcadis Nederland BV, Amersfoort (Copijn, Utrecht)
Facade manufacturer: Octatube, Delft and Lieftink (Geveltechniek, Alphen aan den Rijn)
Developer: EDGE Technologies, Amsterdam
Construction company: J.P. van Eesteren, Gouda
Building technology: Bosman Bedrijven, Amersfoort

Photo source: Ossip van Duivenbode, Schüco

The new administrative building of Triodos Bank with a wooden structure and glass façade, which is energy neutral and can be fully dismantled.

The complex naturally integrates into the landscape with its organic shapes, noble materials, and natural colors.

To integrate the building sensitively into the protected area, a landscape concept was developed that will enhance the quality of this space nurtured for many years.

The grandeur is enhanced by the use of amorphous curves in the structure with a fully glazed aluminum façade.

The window system Schüco AWS 75 BS.HI+ used meets the most stringent energy efficiency requirements with the highest level of transparency.

Extremely high ceilings and the consistent use of wood for floors, ceilings, and columns create a feeling of space as if you were in a "cathedral made of wood."

Visual connections between floors are created by galleries accessed via spiral staircases.

The building with its airy aluminum façade allows for maximum use of natural light deep into the space.