Sustainability Report

Preservation instead of demolition: The massive exterior walls, roof structure, and clay roof tiles were retained. Only non-load-bearing interior walls and some ceiling sections were removed, significantly reducing the need for new materials.

Constructive simplicity: New additions were deliberately designed as simple, easy-to-build structures using common, readily available materials sourced locally and executed by local craftsmen. Four slanted timber frames provide bracing — a minimal, legible intervention.

Material palette: New elements include natural clay plaster inside, exposed screed on the ground floor, pine plywood panels for floors and cladding, pine timber frames, a steel staircase with catwalk, and glass in various formats. All are standard stock materials with clear recyclability, avoiding reliance on specialised manufacturers.

CO2 balance:

• Embodied emissions of new construction elements: ~12 tCO₂e total (≈ 65 kg CO₂e/m² GFA).
• In comparison, demolition and rebuilding in solid construction would typically generate 40–60 tCO₂e (≈ 250–350 kg CO₂e/m²).
• Result: around 75 percent savings in embodied emissions.

Compactness and thermal mass: The existing thick brick walls and compact volume made additional wall insulation unnecessary. Only the roof was insulated, reducing heating demand from ~100 kWh/m²a to ~45 kWh/m²a.

Heating and storage: An air-source heat pump with underfloor heating provides space heating. The massive walls and slab store solar gains from skylights, openings, and glass fronts, releasing heat slowly.

Energy demand and emissions: Annual household demand is ~5,700 kWh/year at 45 kWh/m²a. With the average German electricity mix, this equals ~2.3 tCO₂e per year.

Lifecycle perspective: Over 60 years, the preserved and converted house produces ~148 tCO₂e in total (~794 kg CO₂e/m²). A demolition and rebuild would emit ≥190 tCO₂e (~1,020 kg CO₂e/m²).