Architects: Rundzwei Architekten
Area: 320 m²
Year: 2018
Photography: Gui Rebelo
Project Team: Luca Di Carlo, Ana Domenti, Marc Dufour-Feronce, Andreas Reeg
Facade & Timber Stair: Johannsen Timber Constructions
Windows: Timm Fensterbau GmbH
Pool: Seeigel GmbH
Rammed Concrete: Caerus Construction
City: Berlin
Country: Germany
Cork Screw House, a residential building designed by rundzwei Architekten in Germany, maximizes usable space through innovative split-level design and sustainable materials. Completed in 2018, the house features a base of rammed concrete, upper levels framed in timber, and a cork-clad facade for enhanced insulation and energy efficiency. The design includes flexible living spaces, natural ventilation, and a nearly self-sufficient heating system.
The house features a rammed concrete base for the lower ground living levels. The long-stretched pool’s outdoor walls are lined with this material. Architect Andreas Reeg explained the base was meant to look and feel like it was excavated. This traditional material, applied in layers and manually compacted, creates a textured, porous surface.
Local planning regulations allow a maximum floor size of 100 m², but by lowering the base floors and arranging upper floors in split-levels, the architects increased the gross floor area to over 320 m². The building’s material concept includes rammed concrete for the lower levels and timber framing for the upper levels.
Large-scale glass elements on the ground floor fill the interior with daylight. The upper facades and roof, except for windows and solar panels, are clad with cork, found by the architects in Portugal. This by-product of cork bottle production forms facade panels under heat and pressure. Natural resins in the cork bind the granulate, creating lightweight, durable cladding that is naturally weather and mold-resistant.
Cork has high insulation values, making it ideal for facade cladding, contributing to the building’s energy efficiency and sustainability. It also provides good acoustic insulation and reduces rain sound. The client’s interest in acoustic performance led the architects to this material.
The architects avoided chemical adhesives and construction foam, using wood fiber and cellulose insulation with cork panels. Timber and gypsum fiber boards with permeable paints allow natural ventilation, eliminating the need for active systems despite the building’s low energy standard. A stratified heat storage system with roof-integrated solar panels makes heating nearly self-sufficient.
The house was designed for flexibility. The base includes a bedroom next to the living and kitchen area, with direct access to the sunken pool, which extends into the garden and is shielded by rammed concrete walls. Upper-level rooms, accessed via a central staircase, can be converted into studio apartments. The design includes space and structural provisions for a potential second entrance in the facade.
Project Gallery
Project Location
Address: Berlin, Germany
Location is for general reference and may represent a city or country, not necessarily a precise address.
