Bioclimatic thinking

The young architects from PO have succeeded in camouflaging a timber-frame building clad in untreated, quarter-sawn timber boarding in the middle of a block of houses in Nantes. Beneath its green roof it comprises two almost-identical semi-detached urban residences of 90 m², each with its own outside space. According the architects, the primary challenge was to reduce the environmental effects in terms of both energy consumption and visual impact. They used traditional technical measures (certified timber, sustainable materials, etc.) to achieve a discreet result in relation to the strong exterior.

Completed in 2009, Karawitz's 'Passive House' is something of an abstract replica of a traditional house. While the foundation slab is the only concrete element of a structure in solid wood assembled from very large dimension panels prefabricated in the workshop, its defining feature is its timber cladding, inspired by local barns, which runs across the north-facing windows and continues up over the roof, which is also fitted with photovoltaic panels. With no heating system and a living space of 177 m², it also has a heat recovery ventilation system for fresh air. Closed to the north to limit heat loss, and open to the south to make the most of solar gain, the house has an openwork double skin of untreated bamboo which envelops the framework. Identical shutters fitted to the large south-facing picture windows produce an interplay of shadows and light inside the house. (Sophie Roulet)