The Design

Archicentre Architect Colin Mitchell designed the 5 Star energy-rated, townhouses: Devine Homes will build them. Both properties will reflect good practice in building environmentally sensitive areas and each will have a distinct theme. One will have an environmental focus while the other will be built as a Kidsafe house, promoting child accident prevention in the home. The roofs of each property have been configured to direct water run-off to the tree's roots when it rains.

Upon completion, the homes will be auctioned with the profits being allocated to Kidsafe for Child Accident Prevention programs and the Environment Fund of Frankston City Council.

Frankston's Fig Treehouses
Two specially-designed townhouses have been built around a 100-year-old Moreton Bay Fig tree in Victoria demonstrating innovative construction, environmental design, and child safety practices. The aim is to show that houses can be designed in harmony with the environment.

The Treehouses project, as it is known, is a partnership between Archicentre, Frankston City Council and Devine Homes, who will build the project at cost with proceeds going to KidSafe and the Frankston City Council Environment Fund.

The project posed numerous architectural challenges. To begin with, the brief called for two, three bedroom units to be built on an area approximately 600sqm and which is dominated by the large Moreton Bay Fig tree. The tree has historical significance to the region, having been planted by settlers in the early 1890's and later became a feature of the Frankston Nursery.

The architect was asked to maximise the northern sun to the rear of each property, make both dwellings energy efficient and provide visual and aural privacy to both units, with minimal interference to the tree.

This precluded the effective use of thermal mass and necessitated a construction system that sat 'lightly' on the ground. The building structure is supported on beams spanning a series of well-spaced fine screw piles, carefully slotted in between the established shallow tree roots. The fabric of the building is heavily insulated lightweight cladding on timber framing.

Both houses are oriented with the living areas facing north to maximise the winter solar gain, keeping the bathrooms and service areas to the south and feature cross ventilation for summer cooling.

Critical windows are double-glazed and have been located to maximise passive solar design. Highlight windows have also been employed to avoid crucial overlooking issues - these are above eye level, while still allowing daylight and natural sun warmth to penetrate the living areas.

In order to keep in the heat and achieve a 5-star energy rating, insulation in the roof and floor was increased, and an innovative wall panel system incorporating an additional 50mm of foam insulation was constructed.

Both properties have been designed using water conservation and reduction measures.

Water usage within the home is reduced through the use of water efficient fittings and pressure reducing valves which restrict the pressure of water from the mains.

Rain water is collected for reuse from the sloping roofs; half is collected in tanks to be reused to flush the toilets, the remaining water is diverted to a below ground soaker to nourish the roots of the Morton Bay Fig tree.

Solid paved or concreted areas have also avoided with the use of a permeable gravel cell structure for the driveway and elevated timber decking to again allow maximum ground water collection and dissipation of rain water.

Current solar hot water systems were inappropriate for this site due to the continual overshadowing of the tree.

Both houses use an instantaneous gas fired system linked to a hydronic space heating system - this heats water only as required.

History

The tree was planted around 1890 as a feature in the grounds of what was to become an early Frankston success story, the Frankston Nursery. By the early 1900s the Frankston Nursery was seven acres of shade and glass houses on Cranbourne Road. Not the modern, four-lane carriageway that is there now, but a modest country track running down to a little bridge about where Kelman Street is today. Seven acres with a creek and springs, maidenhair fern in the glasshouses, bulbs and ferns, slipper orchids, lavender, native heath, and seedlings. A short stroll across the sandhills and ferny rises would take you to Reservoir Paddock where the steam trains stopped to fill up with water. A pony ride along sandy tracks took you to the beach.

The tree was planted by first generation Frankston settlers and had stood with Frankston for over 110 years. In July 2003, the tree came under attack by a bulldozer. Local residents rallied around, marshalling passionate support for the tree’s presentation and a heritage order was placed on it. Archicentre, with local architect Colin Mitchell, Frankston City Council, Devine Homes and the local community joined together to come up with a design for a unique housing project built around the tree. It was innovative and collaborative.

It’s a Year of the Built Environment building project, demonstrating one more way in which architects contribute to the fabric of our cities and our lives.