House at Otago Bay

House at Otago Bay | Otago, Australia | 2019
[Topology Studio]

On a lazy bend of Tasmania’s Timtumili Minanya, the River Derwent, the site slopes steeply both to the high-watermark that defines the western boundary and to the freshwater lagoon to the north. From the waterfront to the road the site is embedded with a rock. A delicate layer of topsoil supports indigenous grasses, plants, and she-oaks close to the water and larger eucalypts on the higher ground closer to the road.

Working in sections throughout the design process enabled careful consideration of site levels and detailed exploration of the building’s relationship with the ground upon which it sits. A courtyard, a colonnade, ledges, and terraces soften the building’s interface with the landscape and encourage connections by creating spaces protected from the summer sun, driving rain, and wind.

The approach to the home is via a long drive that skirts a timber-clad boat shed. Arriving at an informal forecourt where the entrance forms a deep recess on an otherwise closed façade. A blank wall to the South curves to follow the site contours and direct views to the opposite shore. Similarly, the timber ceiling is a continuous curve for the length of the home. The entry lifts to address Mt Direction, then dips low to compress the space before lifting again to reveal river views and Kunanyi / Mt Wellington on the opposite shore.

The living space is perched high, drawing the water close and accentuating the drama of living at the water’s edge. In contrast, the lower floor is embedded in the rock, its outlook sheltered as the ground falls away to the water. This west-facing facade pivots to form a soffit lined with suspended masonry. Deep window reveals create privacy and form places of rest. The façade wraps back into the site to define a sun-drenched terrace that in time will feel like a remnant of a previous structure. This terrace was inspired by the remains of a ruined farmhouse embedded on steep rocky ground, overlooking the Amalfi Coast.

Materials were selected to endure a harsh environment and to resist bushfire. Locally sourced masonry has been custom-manufactured to complement the tones of the setting. External timber is hardwood terraces are Australian bluestone. Consideration of sun angles determined the colonnade depth to exclude summer sun. Low angled winter sun warms the polished slab, supplemented by under-floor heating and a combustion fire that manages site fuel loads. Thermal mass, insulation, and double glazing maintain stable temperatures throughout the year.

Programmable external Venetians address the conflict of western views and high solar gains, while cross ventilation and active night purge use evening breezes to drop slab temperatures. Stored coolth is the only air-conditioning needed. The boatshed roof will accommodate solar panels and wastewater is treated on-site. The re-establishment of native vegetation extends habitats from the adjacent reserve.

Refined geometry and a restrained palette of materials result in a home that is precise, yet textured and warm. This project is born of and belongs to this site. Text description by the architects.