Cool exterior, warm interior

The Iceberg: A sustainably designed residential building in hybrid timber construction, located in Berlin's Moabit district

Facade-Open-Folding-Shutters-Residential-Building-Eisberg-Rundzwei-Architects-Berlin-Photo-Gui-Rebelo-WHS66_149_15_700px

Window seat detail – Eisberg residential building – rundzwei architects – Berlin – photograph by Gui Rebelo – WHS66_191_10_700pixel

Maisonette apartment – Eisberg residential building – rundzwei architects – Berlin – photograph by Gui Rebelo – WHS66_049_10_700pixel

Exposed screed flooring with spruce wood ceiling – Eisberg – rundzwei architects – Berlin – photograph by Gui Rebelo – WHS66_096_10_700pixel

Underside view of maisonette roof surfaces – Eisberg residential building – rundzwei architects – Berlin – photograph by Gui Rebelo – WHS66_086_10_700pixel

Wood-aluminum window in maisonette apartment – Eisberg – rundzwei architects – Berlin – photograph by Gui Rebelo – WHS66_080_15_700pixel

rundzwei architects bridged a narrow building gap in Moabit with this timber-hybrid residential building. Facing the street, the "Iceberg" presents a cool minimalist aesthetic with its corrugated white aluminum façade. On the south-facing courtyard side, an external circulation system opens the building to generous light and spacious private balconies. Built primarily from recyclable materials, this low-energy dwelling maximizes its modest 100 m² footprint to accommodate 20 accessible rental apartments.

The building's distinctive geometry creates comfortable open-plan layouts for nine two-room apartments on floors one through four, each offering approximately 55 m² of usable space. These layouts ingeniously connect the north and south façades, enabling cross-ventilation and views in both directions. Every unit features a bedroom with en-suite bathroom and dedicated utility space. The fifth and sixth floors house two larger maisonette apartments, each with 96 m² of usable space. The structure employs a solid timber skeleton frame with load-bearing wood ceilings, timber panel façade elements, sand-lime and reinforced concrete walls, plus steel and timber columns. Prefabricated timber components were employed throughout to accelerate construction and minimize finishing work. The building achieves low-energy performance (KfW 55) through its carefully engineered wall and roof assemblies. The breathable wood and lime plaster surfaces—both structural and interior—actively regulate indoor humidity and air quality. District heating supplies the underfloor heating systems throughout all units.

The architects championed straightforward, locally sourced, and inherently functional materials. Rather than glass, stainless steel mesh secures the balcony railings and stairways. The lift showcases expanded metal cladding finished in a striking golden yellow. Exposed screed floors replace conventional finishes throughout the apartments. Similarly, the spruce wood ceilings remain unclad—simply white-oiled to harmonize perfectly with the floor-to-ceiling wood-aluminum windows on the courtyard side and the timber "window seats" facing the street. Except for screed and plaster surfaces, all building materials are mechanically fastened only, facilitating future deconstruction and recycling.

www.rundzwei.de

(Originally published in CUBE Berlin 01|20)