DETAIL 10.2025: Roofs

Above the Office: Yoga, Jogging, or Partying?

Can architecture keep reinventing the roofscape? Since 2019 we know it can. That year, Bjarke Ingels turned the 400 m sloping roof of a waste-to-energy plant in Copenhagen into a grassy ski slope. Since then, around 10 000 sports enthusi­asts have made the annual climb up CopenHill, Denmark’s highest hill, to glide back down. The concept cannot be repli ­cated everywhere, but it reveals the latent potential of roofs as adventurous urban terrains – spaces far too valuable to be left to languish under layers of bitumen in an age of climate change.

Cooperative housing and cohousing projects had long embraced the communal roof terrace as a place for gardening, celebrating, and dry ­ing laundry together, while also helping to counter the urban heat-island effect and loss of biodiversity.

The movement is now spilling over from housing into office real estate, with global tech giants again leading the way. Ten years ago, Frank Gehry shaped the gently undulating flat roof of the Facebook campus in Menlo Park into a 3.5 hectare parkland above the lagoon. Google is now following suit in the heart of London. At King’s Cross, completion of the BIG and Heatherwick Studio building has been awaited year after year. Some 40 000 t of soil have been piled onto its 330 m roof to plant 250 trees, and foxes have already been spotted digging dens high above the city. In Berlin, things moved faster: on Darwin strasse, Grüntuch Ernst have realised a 2200 m² roof park above 1000 office workstations. Cascading across four sto ­reys, it connects directly to the open-plan offices through sliding glass doors.