Hawkesbury River House

The sun is in the north. The house is only accessible by boat and is located on a steep promontory on the Hawkesbury River, 40km north of Sydney, latitude 33˚ south. The climate is coastal temperate Australian with highs of 38˚C and lows of 5˚C. The site faces east and is seriously overshadowed after 2.00pm in winter by the high headland behind. The site is 15m wide and 90m up a steep hill from a 15.5m waterfront. It is strewn with large rocks and boulders. It is a holiday house with living/dining/kitchen opening to a large deck overlooking the waterfront and with four self-contained bedrooms accessed from an open roofed verandah stepping up the hill at the rear from a small courtyard which captures available sun and is protected from the prevailing winds. The roof profiles are set to maximise solar access from the north in winter and the main butterfly roof also admits south light to the living area while providing a north facing pitch for solar collectors. The roof to the bedrooms is pitched in two directions giving each bedroom natural cross-ventilation and a stepped south wall allows a view of the river from each bed. Rainwater is collected from the roofs via the large valley gutter and stored in water tanks, effluent is treated by a worm activated septic tank. The house had to meet stringent bushfire protection regulations. Built off the ground on steel poles, the undercroft is enclosed to reduce bushfire risk. The walls and floors are timber framed and roof is composite timber and steel to accommodate the large overhangs. External wall cladding is colour coded horizontal corrugated steel – silver for the living areas, black for the bedroom areas and red for the utility areas. The house was designed using a series of physical models employed to take account of the rock strewn site, study solar access and develop the complex roof forms. A plunge pool beside the rear courtyard has yet to be built.