Norra Tornen Penthouse is a minimal space located in Stockholm, Sweden, of which the building is designed by Office for Metropolitan Architecture. The Norra Tornen project started with two inherited building envelopes, the remains of a cancelled project initiated by the former city architect Aleksander Wolodarski. Each a kind of ‘crescendo’ composition of different heights – neither slab nor tower – prohibit the unfolding of an uncompromised typology. Conversely, the opted program, apartments with an emphasis on large outdoor spaces, prevented too literal a translation of the envelopes into architectural form.
Through a kind of ‘Freudian flight forward’ – a passionate embrace of the inevitable in order to conquer and overcome one’s initial fears – the prescribed building envelope was adopted as a given. Its initial vertical segmentation was complemented by a second, horizontal segmentation that gives the buildings’ exterior a single, homogeneous treatment: a rough skin, formed through an alternating pattern of withdrawn outdoor spaces and protruding living rooms. The chosen material, ribbed colored concrete brushed with exposed multi-colored aggregate pebbles, echoes brutalist architecture and that is not by chance. According to architecture critic Reyner Banham, the term brutalist architecture was invented by Hans Asplund, the son of Gunnar Asplund, when referring to a design of his studio colleagues in a letter to his British architect friends.
Concrete at Norra Tornen comes in the form of prefabricated panels – a construction technique that allows work on the building site to continue even below the five-degree Celsius limit which prohibits in situ concrete pouring. Prefabrication also significantly reduced construction costs. This way a design with a wall-to-floor ratio close to 1 – most developers would be discouraged by a 0.5 ratio – was suddenly not an unthinkable proposition. The investment could be channeled in creating apartments with unique layouts, multiple orientations and extra square meters of windows – a precious asset in a country with scarce daylight for half of the year.