TRÆ: Materials Before Form

TRÆ in Aarhus is a groundbreaking example of how recycling and sustainable choices can create a new aesthetic that both respects the environment and challenges our perception of building design.

In the South Harbor District of Aarhus, overlooking the cranes and silos, stands TRÆ – literally meaning tree or wood in Danish. It’s a 20-story office building where sustainability and reuse have shaped its design. Instead of designing the building first and then selecting materials, the architects reversed the process: they identified available recycled materials and created the structure accordingly.

A Building That Doesn’t Mimic the Existing

TRÆ was designed by Lendager through an unconventional process. The developer reached an agreement with Aarhus Municipality to construct an office building with minimal environmental impact. But rather than starting with a fixed form, the architects let the materials dictate the building’s appearance.

Wood and Recycled Materials

The goal was to use as much wood as possible, as wood naturally stores CO2 and reduces carbon emissions. The supporting structures consist of massive wooden beams, the floors are solid wood, and reclaimed wood is used for flooring. Window frames are also partially made of wood. However, for fire safety reasons, it was not possible to create a wooden facade. Instead, the facade was built using recycled materials.

Turbine Blades on the Facade

For instance, old wind turbine blades, which would otherwise have been discarded, were cut and repurposed as sunshades. Since wind turbine blades are made of fiberglass – a material that does not biodegrade – their reuse has a direct environmental benefit.

Additionally, corrugated aluminum sheets, also known as trapezoidal sheets, that were otherwise destined for disposal were flattened and combined with metal panels from damaged mailboxes to create a unique facade pattern. The facade’s appearance changes with light and weather conditions, giving the building a dynamic, ever-evolving character.

Inspired by the Industrial Harbor

TRÆ draws visual inspiration from the surrounding industrial harbor. Instead of resembling the modern office buildings nearby, its shape is inspired by the harbor’s silos. The building is tall and slender, occupying as little ground space as possible – a requirement from the municipality, as it is situated close to an area with small cultural institutions and social initiatives.

TRÆ also includes two smaller six-story buildings connected by walkways. These bridges take inspiration from the industrial structures in the harbor, allowing people to move between buildings without going outside. At the same time, they help reduce the building’s footprint by minimizing the need for additional structures.

A New Aesthetic for Sustainable Architecture

TRÆ demonstrates how architecture can emerge from available materials rather than starting with a predetermined idea. The building challenges traditional notions of beauty and encourages us to rethink imperfections and randomness in architecture. Perhaps this approach is exactly what we need if future construction is to be more sustainable. The question remains: how much room are we willing to give to the imperfect in our cities?