A line of military uniforms, crafted in stiff layers of denim, stands at the top of a polished concrete staircase, each topped with a busby, bearskin or sharp-peaked cap. At the other end of the building hangs a row of heavily sculpted jeans, with great cod-piece pouches bulging from their crotches. Elsewhere there are reins and bridles, straps and saddles, and even a tailored denim suicide bomber vest. Here in Amsterdam, this could easily be the headquarters of a kinky fetish-wear empire, but it is in fact the new home for Dutch jeans company G-Star Raw – purveyors of “modern metropolitan denim” – designed by the Netherlands' own Office for Metropolitan Architecture.

Extending 140m along the edge of the A10 motorway in the industrial southeast of the city, the €40m building squats like a glowering aircraft hangar. Its dark concrete shell stretches out to envelop a world of glass boxes that appear to slide past each other, the furthest cube shooting right out of the building in a dramatic cantilever towards the road, wrapped in hoardings proclaiming the latest season's trends. Emblazoned with a 20m-long G-Star logo, it is as close to building-as-billboard as OMA has yet come, a literal expression of Robert Venturi's “decorated shed”.



“We've never been this vulgar,” says the practice's founding partner Rem Koolhaas, sitting in the building's boardroom, flanked either side by neat men in military denim jackets, like officers from some future fashion police. He explains how they won the project by brazenly conflating G-Star's brand values with their own, aligning their manifestos, house styles, ways of working and even presenting a shared aesthetic of raw industrial chic – with concrete and steel fragments of OMA buildings overlaid on to G-Star models. “It is a form of method acting,” says Reinier de Graaf, the OMA partner who led the project. “You engage with a brand so intimately that the brand takes over you.”



Decorated shed … sliding hangar doors can open up the entire northern elevation. Photograph: OMA/G-Star Raw Photograph: OMA/G-Star Raw

The resulting building is as close to a physical manifestation of the Raw brand image as you could get, without using pre-crumpled columns of heavily starched denim. Floors are aluminium and white resin, while hefty steel trusses zig-zag through the rooms, everything held together with exposed brackets and bolts. All that's missing is the smell of engine oil and a techno backing track.

“Our initial idea was to clad the frame in bits of Somali shipwrecks, as the equivalent of stone-washed jeans,” grins De Graaf. “But we were told that the stone-washed look was going out of fashion.” Instead, big slabs of black concrete envelop the offices, which rise at either end of the building, before spanning like a great bridge above the gargantuan “creative nucleus” at the centre of the complex.



Conceived as a contemporary turbine hall of denim, this vast space is an airy world of double and triple-height studios, all connected on split levels in a big open-plan shuffle. Enticing views are framed between departments of finance and fashion, the pattern-cutting and jeans-sculpting on show for all to see, while felt-lined walls ensure a remarkably soft acoustic for such an immense shed.



Staggered studios … the open-plan hall features split levels of offices and design departments. Photograph: OMA/G-Star Raw Photograph: OMA/G-Star Raw

“They gave us the model of an aircraft hangar,” says De Graaf. “But I'm not sure they expected us to take it quite so literally.” Outside, a row of four-storey high glass doors, sourced from a hangar manufacturer, lines the principle elevation towards the highway, forming a monumental sliding screen which can be entirely drawn back for events and fashion shows on the forecourt. Between this screen and the internal staggered facade is what the company calls its “Raw space”, a 20m-high “flexible” zone which feels, now built, like a bit of a useless leftover from the bigger conceptual idea – a theatrical trick that works from the motorway, but that seems a bit redundant up close.

“You experience the building in motion, from the car,” says De Graaf, “so we did a lot to make it as long as possible, to maximise your exposure to the brand. It surrenders to the notion of being a billboard, rather than resisting the idea of highway architecture.”



Fetish-wear … a polished concrete staircase rises to a line of denim military uniforms. Photograph: OMA/G-Star Raw Photograph: OMA/G-Star Raw

Drawing on 1950s America, and the later buildings of Mies van der Rohe, the G-Star HQ fits into what has been called OMA's “generic” phase, what De Graaf describes as “the more down-to-earth, somewhat understated oeuvre that has ensured since the CCTV building in Beijing – after which we abandoned an obsession with form and a desire to demonstrate a certain amount of virtuosity.”

He places it alongside their Rothschild bank in London, completed in 2011, the Shenzhen Stock Exchange and the mixed-use goliath of de Rotterdam, both finished last year, all of which comprise rectilinear volumes dressed in a relatively restrained corporate clothing – “as an antidote to the formal extravagance of the 90s.” He recounts the legend of a memo, sent by Koolhaas to the entire office from a far-flung branch of the Four Seasons hotel, which set the new agenda: “Use 90 degrees only. Good luck, Rem.”



This general shift is also, he says, a product of the practice's trajectory away from the maverick leadership of an individual genius, as Koolhaas reaches his 70th year. “OMA started as a group of people united by a shared conceptual mentality, but then the work became the person. Now there is a return towards a more collective ownership, which is breeding this kind of calmer architecture, rather than every building being a magnum opus.”



Staggered section … the shifted floor plates allow views through between departments. Photograph: OMA/G-Star Raw Photograph: OMA/G-Star Raw

The visceral thrill of encountering many of OMA's buildings has always been in the number of conflicting and contradictory ideas they contain in their very fabric, standing as energetic essays wrought in steel and glass, mesh and polycarbonate, punk mash-ups of the deluge of ideas racing through their office. By emulating the generic blandscape of speculative office blocks, is the work in danger of losing its edge, producing insipid cover versions of Norman Foster with a Dutch twist?

The G-Star building, Koolhaas maintains, is important for the office precisely because it allowed them to flirt with the boundaries of their practice, and embrace commercial realities as never before.



“We identified a number of things G-Star is proud of, with a number of things we are never able to be proud of, because we would be criticised for it – like crudeness,” he says. “Both of our companies were founded in the Netherlands, and crudeness is something that could be said to be very Dutch, but it is something we are not usually allowed to celebrate. This building has allowed us to be more explicit about our values than we have ever been before.”



The values of Raw – what G-Star's global brand director, Shubhankar Ray, defines as “unfiltered, unprocessed, crude, naked and harsh” – translates, in architecture, as a certain license to have a laid-back approach to detailing. The facade is bolted on to the structure with clunky brackets, and there are points where things don't quite seem to fit. But it all hangs together with what De Graaf calls “a casual elegance,” in line with the rough and rugged brand marriage of OMA and G-Star – or, as Ray puts it, “two brands having unprotected sex”. (The building presumably being their bastard love child.)



Building-as-billboard … G-Star uses the cantilevered glass box as an extended advertising surface. Image: OMA/G-Star Raw Photograph: OMA/G-Star Raw

Ultimately, it is the enthusiastic flirtation with the brand that makes this an interesting project. Koolhaas describes the model of OMA as “a cross between a fashion house and a newspaper office,” and the practice has long had a promiscuous relationship with the world of branding and advertising through its sister think-tank, AMO. At once complicit and cynical, the office immerses itself in the commercial world with opportunistic glee, while also managing to retain a critical distance, often pushing clients to the edge of their comfort zones. For Prada, whose experimental flagship stores, fashion shows and art foundations the practice has designed for the last decade, they also created adverts depicting fake handbags being sold by illegal street vendors. Similarly, a pitch for Adidas featured an overweight Maradona bursting out of his three-stripe tracksuit, alongside other unsavoury characters sporting the brand – although that didn't seem to go down so well in the world of squeaky clean sportswear.

“It is interesting that we founded AMO specifically to deal with aura creation, to go beyond buildings,” says De Graaf, who has headed up that side of the office since 2002, and overseen work for Heineken, Ikea and Condé Nast – as well as redesigning the EU flag. “But we have now come full-circle: our most extreme example of branding actually isn't a logo, but a building.”



So will Koolhaas be swapping his trademark Prada wardrobe for a pair of wet-look jeans and a denim Stasi coat? He dodges the question with a wry smile as he leaves the room, dusting down his Prada sweater.

