This project explores a singular model of attached houses in order to maximize densification of a typical Parisian outskirts pavilion fabric. The two back to back houses share the site’s steep topography at the foot of Noisy-le-Sec fortress hill. They are sheltered under a single bi-plan roof to accompany their half-level shift going up the slope.  The building’s implantation pursues the frontline of downstream houses following the route’s curve, keeping an important distance from the upstream house to create a visual breakthrough towards the hill’s natural landscape. A void created in the roof‘s volume opens the back side of the front house to that landscape, reducing simultaneously cast shadows to the neighboring plot.

To connect the project to its site, the back part’s upper floors are suspended over an independent wall joining horizontally the hill’s slope. Their in-between glass screen void continuity is ensured by moving back the supporting column, revealing the voluntary distinction between structural framework and filling panels concept. The low carbon reinforced concrete choice allows to mold a hull anticipating all project’s spatiality, generating all at once an important inertia mass. All filling materials are raw and recyclable, timber, anodized aluminum and glass. Their implementation addresses the specific situation of each side of the building: a single timber mega-panel forms the street side facade occultation integrating roller and butterfly shutters as well as a guardrail. On the opposite view-free southeast side a combination of glass walls including the terrace’s roof deploy every inhabitable space towards the landscape and sky horizons.

The forecast implementation of several removable occultation layers, interior and exterior, turns both facades into adjustable envelopes, capable of increasing or reducing their thermal resistance and porosity according to their exposure and meteorological conditions. Thermal inertia of the structure, as well as incorporated vegetal masses act like a «heat-freshness tank», slowing the rate of temperature change in all interior premises following the day-night course. The building’s capacity to auto-regulate naturally its comfort seeks to respond, effectively and sustainably to the seasonal variations amplitude, and furthermore to the longer term climate ones. These architectural devices are perfected by the stairwell use as a ventilation shaft connecting and naturally aerating all four levels of each house including the basement. That type of vertical habitat also looks forward to potential uses reversibility or functional divisions, each floor acting as a single activity open space.