11.4 Clovelly, New South Wales

This award-winning Sydney renovation turns site constraints into opportunities, creating a spacious, light-filled home that is a showcase for leading-edge domestic water management. The renovation reduces the existing home’s environmental impact and incorporates innovative technologies as an integral part of the architectural expression.

In pursuit of their philosophy of making the principles of sustainability an essential element of the design approach, the designers extended their concerns to incorporate the principle of universal access and adaptability with the home designed to accommodate an occupant with limited mobility.

BACKGROUND

Location and site

The house is in Clovelly, an inner coastal suburb of Sydney. Located within a warm temperate climate zone, it enjoys mild winters and warm summers moderated by cooling sea breezes. Rainfall is relatively high at around 1,200mm per annum. The architect describes the site as ‘complex and constrained’ due to its tight 234m2 area and east-west orientation, which limits the potential for easy solar access. The existing house was a small, ‘dark and poky’ semi-detached dwelling with its long façade facing south.

Design brief

The owners wanted to open the house up to the garden and to natural light, a typical requirement for many inner-city renovations. Less typical was the need to meet the spatial and accessibility needs of an occupant with an ambulant disability. The owners were also keen to address key environmental issues and push boundaries where possible. They were particularly keen to ‘do something significant’ in response to Australia’s pressing need to conserve water. [See: 7.2 Reducing Water Demand]

DESIGN RESPONSE

The key design challenges were to manage the site’s poor solar access, maximise spaciousness on a tight site, and integrate the resulting open plan format with thermal and acoustic comfort.

Whilst the majority of the structure of the existing house was retained, the entire back wall was removed to accommodate a two storey addition. The addition encompasses a living area on the ground floor, and a home office, main bedroom, bathroom and kitchenette on the upper floor. At its centre are a staircase and void, creating a pivot around which the home operates. The northern wall along the staircase accommodates an extensive library.

The geometry of the addition is based on a series of solid and open intersecting cubes, carried through into the design of the landscape. This underpinning design theme helps to provide a sense of unity, clarity and space. Urban design issues of privacy, scale and massing were respected and the approvals process was relatively straightforward. The house integrates a range of innovations including a vertical ‘green wall’ for greywater treatment, the first of its kind in Australia. [See: 5.13 Green Roofs and Walls]

Passive design strategy

The renovated house is designed to minimise the need for artificial heating, cooling and lighting and avoids reliance on mechanical systems like air conditioning in order to achieve ongoing cost savings and environmental benefits.

Natural cooling in summer is achieved through strategic placement of openings for cross ventilation. The double height void, as well as providing a sense of space, creates natural ventilation through the ‘chimney effect’. Warm air is exhausted through high-level glazing and skylights, which in turn pulls fresh cooler air through the house at ground level. The west-facing wall can be opened up at night to encourage heat loss.

Shading on the west-facing glazing minimises unwanted heat gain in summer. On the ground floor, a deep recess provides protection. At a higher level, adjustable external louvres screen out low angle western sun in summer whilst admitting it to warm the living areas in winter. [See: 4.6 Passive Cooling]

Double height voids and large glazed areas can be particularly problematic in terms of heat loss. This is counteracted to an extent by the solar powered heating system, however in retrospect the architect would have decreased the amount of south-facing glass and incorporated doubleglazing to improve winter comfort. Draught protection on doors and windows helps to retain heat in winter. [See: 4.5 Passive Solar Heating]

Thermal insulation under the roof and above the ceiling is an important part of the passive design strategy, minimising unwanted heat loss and gain.

The concrete ground slab is covered with a battened timber floor. This reduces utilisation of the slab’s heat storing properties, but allows quicker warming and cooling of the space. Similarly, the metal-clad brick veneer wall construction reduces the ability of the bricks to store heat but allows quicker warming and cooling of the space. [See: 4.9 Thermal Mass] Light-coloured internal walls, skylights and clerestory glazing minimise the need for artificial lighting during the day.

A joint initiative of the Australian Government and the design and construction industries.

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