TRÆ

TRÆ holds a triple meaning in Danish: tree, timber and three. Comprising three connected volumes of office spaces, common facilities and a restaurant, it is located in Aarhus’ former industrial harbour. Existing social realities are taken into account by involving homeless people in upkeep – and TRÆ also houses a volunteer initiative providing daily meals to families in need. The building’s facades are made of industrial leftovers creating a material familiarity to the surroundings, but arranged in such a way that they recall birch bark in tone and texture: mottled, imperfect, and alive.

TRÆ began with a radical goal: to prove that a high-rise could be built from waste and wood without compromising safety, economy or quality. We wanted to show that large-scale circular buildings can be beautiful, buildable and profitable. From this basis, TRÆ was conceived as a boundary-pushing lighthouse project that also had to fulfill all current requirements for a space efficient, high-performance office environment. This made for an intense process of collaboration between all project actors, including specific innovation processes for new solutions and a close dialogue with municipal authorities. The site itself posed many constraints including salty sea air, explosion safety zones from nearby industry and air pollution from a local power plant that all had to be handled in an already complex design. Also opportunities – one being the addition of an undulating public pedestrian bridge, that starts at ground level and snakes its way up to Aarhus’ new high line project.

The primary structure of TRÆ consists of mass timber columns with cross-bracing and CLT floor slabs, using low-carbon concrete only in the cores to ensure stability and fire safety. To achieve the lowest possible CO₂ footprint, the project operates within two material ecosystems – the circular and the biogenic. This dual approach conserves resources, reduces emissions, supports biodiversity, creates local jobs, and turns waste into architectural value. The façade system is built from timber cassettes clad with aluminium sheets salvaged from industrial and farm roofs and water-damaged postboxes. Nearly all visible surfaces are reused, upcycled, or biobased: wind turbine blades provide solar shading, while reused windows, waste textiles, and PET felt form acoustic surfaces. Trees relocated from municipal sites establish an instant, mature landscape. TRÆ has generated new technical standards and regulatory pathways, standing as a benchmark for the sustainable high-rise of the future.