The client had owned this sloping plot in the residential area of Wiehl, in the Oberbergisches region, for years. Looking to develop it with two multi-family apartment buildings, he turned to bonfanti architects. The Wiehl-based firm responded with an elegant linear structure that bridges the gap between the established neighborhood above and the single-family homes below—creating a harmonious urban transition.

The design's central philosophy: bridge the urban fabric by respectfully integrating the new structures into their context while establishing a distinct architectural presence through refined form and materiality. The elongated footprint follows naturally from the site's geometry and local zoning requirements. The two buildings mirror each other precisely—each containing five units and its own entrance. Housing types are thoughtfully designed for accessibility, whether for families, couples, or single residents. Rather than a traditional stairwell, an open staircase connects spaces across two floors. Every apartment enjoys generous south-west-facing loggias or terraces with valley views, while maisonettes and one wheelchair-accessible ground floor unit have private gardens. The slope presented a clever opportunity: parking is arranged on two levels between the buildings, maximizing efficiency while maintaining barrier-free access to all residences. Sustainability shaped every material decision. Highly insulated exposed concrete walls are lined with mineral insulation and lime plaster inside. Local spruce frames the windows, entrance systems, sliding shutters, and terraces. The north roof is clad in clay tiles; the south side features photovoltaic panels—with a tenant electricity model option. The result exceeds the highest efficiency standards: advanced heat pumps with brine-water technology, heat-recovery ventilation, integrated fresh water heating, and onsite energy storage work in concert. Recessed glazing provides passive solar control, while the heat pump delivers passive cooling when temperatures rise. All parking spaces come pre-equipped for electric vehicle and bicycle charging infrastructure.

www.bonfanti-architekten.de

Photography Credits:

Wolfgang Grümer
www.gruemerfoto.de

(Published in CUBE Cologne Bonn 03|22)