A western Hamburg property came with an existing structure slated for demolition – a flat-roofed 1960s bungalow. Yet after careful examination, the property revealed remarkable qualities: both its structural integrity and architectural design were exceptional. Bungalows of this era marked the golden age of residential architecture. Once post-war housing shortages eased and economic prosperity emerged, these single-family homes drew inspiration from American bungalow design, featuring innovative floor plans and seamlessly integrated indoor-outdoor living. Sieckmann Walther Architects recommended preserving rather than demolishing the building. The solution: comprehensive renovation complemented by a thoughtful vertical extension that would provide much-needed space.

The distinctive roofline detail – an accentuated cornice with continuous roof edge cladding – became the design signature for the new storey. Framed in anthracite zinc sheet, the extension rises as a black timber slat façade with seamless, floor-to-ceiling glazing that mirrors the ground floor openings below. The original building received a comprehensive energy upgrade: wood fibre interior insulation, triple-glazed wood-aluminium windows, and fresh white exterior plaster. Constructed on-site using lightweight timber frame methods with cellulose insulation, the extension required no foundation reinforcement. The striking black-and-white contrast reinforces the building's cubic geometry while creating visual rhythm throughout the interior as well.

Grey energy – the total energy embedded in manufacturing, transporting, storing, selling, and disposing of a product and its components – tells a compelling story here. By rehabilitating rather than demolishing, the project conserved roughly 120,000 kWh of embodied energy – equivalent to the building's heating needs for the next 35–40 years. The lightweight timber frame construction of the extension further reduced environmental impact. Above the roof, unbuilt sections received rafter insulation – a best-practice thermal strategy that creates a protective envelope over the entire roof surface, safeguarding both the interior spaces and the structural system below.

www.sieckmannwalther.de

(From CUBE Hamburg 02|20)