In the French capital’s 18th arrondissement, the new building on Rue Marx Dormoy melds with the Parisian streetscape. Anchored by a pair of storefronts, the social housing complex meets the urban context with a crisp five-storey frontage, seamlessly blending in with the block’s mid-rise rhythm. But the quiet and contextually attuned infill project is also a showcase of carbon-conscious design, boasting wood framing and hempcrete insulation behind its understated facade.

Designed by local firm Barrault Pressacco, the recently completed project integrates 15 homes — and a pair of narrow inner courtyards — into a relatively compact 1,400-square-metre urban site. Developed by public agency Paris Habitat, the intimately scaled housing complex uses a quintessentially Parisian typology, the mid-rise courtyard building, as the springboard for a new materials palette.

Below grade, the foundation is one of the relatively few all-concrete elements, with a pine and concrete structure rising from the slabs. While the seven-storey building’s party walls are also made from pre-cast concrete, gypsum fibre panels are affixed to the interior of the building’s timber structure, serving as the back of the formwork into which layers of hempcrete insulation were sprayed.

A close-up of hempcrete.

A composite of hemp, lime (which acts as a bonding agent) and water, hempcrete offered “self-supporting insulation, totally rigid after the drying process,” according to the architects. Both an insulating material and a vapour barrier, the efficient material offers exceptional thermal mass — preserving heat in warm weather and keeping out the cold in winter — with a low carbon footprint. Sprayed in thick layers, the insulation was finished with an interior coat of lime render.

Prioritizing sustainable design and livable spaces in equal measure, Barrault Pressacco’s holistic approach also prioritized breathable, generously sized suite layouts. A complement to the thick, thermally massive hempcrete walls, the building’s two greenery-filled inner courtyards bring ample light and fresh air into kitchens and bathrooms, reducing heating and cooling costs through cross-ventilation.

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Ahead of planned French sustainability legislation that mandates new public buildings to be built with — at least — 50 per cent natural materials such as timber, the modest apartment building in Paris’ 18th arrondissement offers a vital framework for the future.