Obwaldner Kantonalbank OKB, Sarnen

The roof landscape forms the building’s inner courtyard on the first floor and is conceived as an interpretation of a gorge forest. At ground level, a carpet of mosses and ferns creates a cool, shaded understorey, while the facades are wrapped in a planted curtain that cascades down from the roof.

A central challenge was to realise this intensive greening above a column-free atrium within the structural limits of the building.

Beyond its compositional role, the courtyard acts as a climate-adaptive system: the moss garden functions as a sponge, retaining rainwater, cooling the courtyard and absorbing sound. The vertical greening shades the south- and west-facing courtyard facades, reducing heat loads and cooling the adjacent interior spaces.

On the upper floor, the combination of moss garden and plant curtains modulates daylight, producing a distinctive, softly filtered light atmosphere in the interior.