The world’s first upcycled timber high-rise has opened in Aarhus, clad not in aluminium or glass but in decommissioned wind turbine blades carrying a carbon footprint 96 per cent lower than the material they replaced.
That is according to Copenhagen-based architecture and upcycling practice Lendager, whose TRÆ development spans a 3.62-acre former industrial harbour site in Denmark’s second city and now stands as the nation’s tallest timber structure at 78 metres — 20 storeys of cross-laminated timber slabs and glulam columns anchored by concrete cores, completed against a conventional concrete benchmark at 26 per cent lower CO₂ and without formal green-building certification of any kind.
The turbine blade cladding did not come easily. Lendager spent months on fire testing and façade modifications to prevent flame spread before regulators would approve what amounts to a new category of building component — decommissioned epoxy-fibreglass blades, cut and reconfigured as external solar-shading devices. “Burning it or putting it in the ground is environmentally insane, but it’s an insane big potential,” said Anders Lendager, the firm’s chief executive.
Of the 26 per cent emissions reduction, 21 per cent is attributable to the timber-led structure and five per cent to the integration of reused materials, including the blades. The team applied what Lendager describes as a value-driven framework — one that lets environmental strategies evolve alongside design development and technical problem-solving rather than locking them to a fixed checklist from day one — a deliberate decision that ruled out formal certification throughout.
And whilst the emissions numbers carry weight, the project’s broader logic runs further. TRÆ’s name carries three meanings in Danish — tree, timber, and three — the last a reference to the trio of rounded interconnected towers rising from a compact waterfront footprint, with two six-storey volumes flanking the primary 78-metre tower and an undulating pedestrian bridge linking the ground plane to Aarhus’s emerging elevated walkway network.
Local homeless residents were involved in aspects of site life and maintenance throughout the project, whilst a volunteer initiative operating from the same ground floor provides daily meals for families in need — social infrastructure. Lendager chose not to certify against any external framework, preferring a model where measurable outcomes set the standard rather than compliance checklists.
Lendager has framed TRÆ not as an exceptional-conditions showcase but as a replicable model — one that holds at real-world scale because the regulatory and fire-testing groundwork has now been done. Whether the turbine blade concept travels beyond Aarhus will depend on how quickly blade retirement rates grow, and whether other project teams are prepared to pick up the approval pathway Lendager has already cleared.
The global wind industry is projected to retire tens of thousands of blades through the 2030s. TRÆ is the first building in the world to make a structural case for a component that belongs in the façade — not the landfill.
