Modular flats stacked seven storeys high a first for New York

In a city awash with ambitious architecture, a seven-floor structure boasts a distinction of its own, as the first multi-storey, modular-built apartment block in New York, the apartment capital of the United States.

Called the Stack, the building near Manhattan's northern tip aims to show that while stackable flats can save time and money, modular doesn't have to mean monotonous. The building interiors defy their boxy components with varied layouts and finishes.

Construction from prefabricated sections has been around for decades, but interest has grown recently around the United States, with the world's tallest modular building, a 32-storey tower, rising in Brooklyn.

Advocates say modular building can trim costs and timetables. Still, the technique has an image problem in that it is sometimes perceived as cheap.

"'Prefab' and 'modular' have somewhat of a stigma associated with it in some people's minds, whether it's appropriate or not," developer Jeffrey Brown said. "[But] this approach can really produce cool buildings."

The Stack's 28 flats were formed from 59 modules. The rectangular components are all 3.75 metres wide and 15 to 18 metres long, but with different interiors. The modules sit roughly side-by-side, but their interior layouts interlock to form flats of various sizes and configurations. Construction began in autumn of 2012. The foundation, basement and first floor were conventionally built, while the steel-framed modules were fabricated in the state of Pennsylvania.