Mona Vale House / Choi Ropiha

Architects: Choi Ropiha
Location: Mona Vale, NSW, Australia
Client: Graeme Jessup & Barbara Elkan
Environmental Systems: Graeme Jessup
Landscape: ExParrot
Engineering: Simpson Design Associates - Northrop Engineers
Construction: Graybuilt
Photographs: Brett Boardman

The client for the project has a long standing interest in building sustainability developed through working at the Sustainable Energy Development Authority, a government agency in sustainability.

With this interest in mind, the client approached Choi Ropiha to design a house that would demonstrate and test a number of active and passive sustainable initiatives whilst accommodating a contemporary coastal lifestyle.

The project is sited on the south side of Mona Vale Headland and has expansive views over Mona Vale Beach to the south. This south facing aspect and the narrow site proportions combine to limit the passive design potential and accordingly establish the key design challenge for the project.

Our response orients the house toward the view to the south, but opens up the roof at the centre of the house with a large north-facing skylight to admit winter sun to the south facing living areas and to trap and hold the warmth of the winter sun using the thermal mass of the structure.

The building is of reverse veneer construction. It utilizes low embodied energy and low thermal mass timber cladding to the outside and heavier thermal mass of concrete and blockwork to the inside.

The house is able to be ‘zoned’ to 3 separate areas; the sunroom at the back, the bedroom and hallway, and the living area to the front. This assists in the retention of heat in the winter months.

Cross ventilation is carefully considered through the whole house. The front living area ventilates through a series of louvres in a bank of high level clerestory. The bedrooms also have cross ventilation via fanlight windows above doors.

Other sustainability measures include a 15,000 L rainwater storage tank combined with grey water recycling to minimise water usage, the use of evacuated tubes for in floor hydronic heating and hot water supply, and photovoltaic solar panels to provide electricity back to the grid.

The house is a ‘test-bed’ for these and other sustainability initiatives and the performance of these will be measured after occupancy.