Kö-Bogen II Düsseldorf

There is a kind of ar­chi­tec­ture that pro­duces built space yet is still amenable to life outside and to more besides, that adopts a cred­i­ble stra¬tegy for dealing with climate change in cities, extreme heat­waves for in­stance. The Kö-Bogen II project by in­gen­hoven ar­chi­tects boasts the largest green façade cur­rently in ex­is­tence in Europe – five miles of horn­beam hedging line the roof at a height of 89 feet along with two sides of the main build­ing facing Gustav Gründgens Square. A façade some 89 feet high and 394 feet long running along Schad­ow­strasse is, by con­trast, glazed. Ex­panded-mesh slats help struc­ture the feel of the in­te­rior here, their degree of trans­parency varying from closed to open as a func­tion of from where they are viewed.

Christoph In­gen­hoven has been pro­vid­ing fresh impetus for recon­ceiv­ing the centre of his home city since 1992. Com­ple­tion of Kö-Bogen II brings Düssel­dorf’s great­est ever ur­ban-plan­ning repair project to a suc­cess­ful con­clu­sion. Key mile­stones in this process were Daniel Libe­skind’s Kö-Bogen fin­ished in 2013 and the de­mo­li­tion of the “Mil­li­pede” el­e­vated road that same year. The road’s demise altered spatial per­cep­tions so markedly that the com­pe­ti­tion for Kö-Bogen II had to be re-ad­ju­di­cated – in favour of the tender by in­gen­hoven ar­chi­tects.

The unusual out­lines of the new two-sec­tion office and com­mer­cial en­sem­ble, which con­tains over 441,000 square feet of floor­space for re­tail­ing, cater­ing and of­fic­ing pur­poses, were dic­tated by the nature of the plot avail­able. The sloping green façade to the trape­zoidal five-storey main build­ing and the greened sloping roof to a smaller tri­an­gu­lar struc­ture dive down dy­nam­i­cally onto Gustaf Gründgens Square from either side. Anyone ap­proach­ing from Schad­ow­strasse or Berliner Allee has an unim­peded view of the listed post-war duo com­pris­ing the “House in Three Slices” (1960, HPP Archi¬tects) and a theatre build­ing (1970, Bern­hard Pfau, re­fur­bished by in­gen­hoven ar­chi­tects) as well as of the royal court garden behind.

The sloping roof to the tri­an­gu­lar build­ing has been grassed over and can be walked on – a picnic lawn that further con­tributes to en­hanc­ing the at­trac­tive­ness and social ben­e­fits offered by the new centre. Sus­tain­abil­ity and ar­chi­tec­ture have long been com­pan­ions for Chris¬toph In­gen­hoven. He sum­marises his ap­proach as being su­per­green® – a holis­tic system of in­sights and as­pi­ra­tions that is being on­go­ingly refined. One of the central themes is the thought of giving the city as much green back as pos­si­ble.

Kö-Bogen II pro­vides a po­ten­tial “con­tem­po­rary re­sponse by cities to climate change” with its green façade. The façade’s veg­e­ta­tion takes the form of 30,000 horn­beam plants. It acts as a natural cold storage device and hence reduces the in­ner-city warming effect, it con­serves rain­wa­ter, thus closing a gap in the water cycle, it binds carbon dioxide and par­tic­u­late matter, it sup­ports bio­di­ver­sity and it also im­proves human well­be­ing in general. It is only logical, then, that in­gen­hoven ar­chi­tects also opted for a sus­tain­able premium product from Germany where the iron­mon­gery was con­cerned.

FSB pro¬ducts are cer­ti­fied to the strin­gent pro­vi­sions of ISO 14025/German Sus­tain­able Build­ing Council (DGNB) and are ideally suited to such pro­jects. Resort was had here to handle 1078 and the re­turn-to-door variant 1088, both au­thored by Christoph In­gen­hoven himself. Their design draws on the basic idea from a handle classic by Robert Mal­let-Stevens, which is sup­plied as model 1076 in the FSB range of prod­ucts. In­gen­hoven in­ter­prets the “Frank­furt Model” afresh by varying the shape of its mitring and grip. The tran­si­tion from the cir­cu­lar styling of the handle’s shank to its flat­tened grip section has been ac­com­plished to par­tic­u­larly ap­peal­ing effect.