Sustainable House Day, Wallaby Way House, Horseshoe Bay, Magnetic Island, North QLD

House Name: Wallaby Way House

Construction type: Steel frame for floor and roof. Timber framed walls clad with fibre cement sheeting. Corrugated roof sheeting. Raised timber flooring. Designed specifically to enhance the experience of living in the tropics.

Climate Zone: Townsville is located in the Dry Tropics – there are two seasons: hot and humid (November to April), the wet season, and a warm to hot dry season with low humidity for the other half of the year.

Design/Build Process: New home, built by the owner’s engineering  / construction company (Brice Engineering) as a ‘spec house’. The architect was Zammi Rohan of Troppo Architects, Townsville.

Summary
This spectacular new home was designed with the specific and primary intent of allowing and encouraging occupants to be ‘close’ to the outdoors. Boundaries between inside and out are both permeable and removable. The entire building can open up to let in -  the tropical breeze or the sound of rain. Wide overhangs and copious verandah spaces allow the building to remain open and used even during relieving summer downpours. The building is about living in and with the tropics. The home features steel and timber structural elements, and thermally responsive fibrecement wall cladding in combination with highly openable windows, doors, louvres, shutters, timber batten breezeways and insect screens.  The roof is corrugated iron sheeting with air-cell type insulation.

External Walls
Only about 20% of the external walls are actual walls, the rest is windows, doors, louvres, shutters, timber batten breezeways and insect screens. Walls consist of wooden frames with fibre cement sheeting (not insulated).

Internal Walls
Timber framing and sheeting to maximise the building’s responsiveness to changes in temperature. Not insulated.

Roof
Colorbond corrugated iron sheeting in “Surfmist”. Roof lines are angled throughout to ensure the right level of exposure to the elements, plunging downwards where protection is most required and soaring up where light is required.
The roof is fully insulated (air-cell insulation) and has generous overhangs to protect the walls from direct sunlight.

Floor
Particle board floor with bamboo overlay. Steel floor frame.

Window Treatments
Windows consist of louvres (grey glass or cedar timber blades) and plantation shutters. Translucent sheeting is also used.

Heating and Cooling
Internal verandahs cut paths through the house to facilitate circulation of breezes and ventilation.
Trees were retained close to the house to provide shade.

Water Heating
26L Rheem Integrity gas instantaneous water heater (5-star energy efficient).

Lighting
Energy efficient compact fluorescent down lights.

Energy
Water efficient shower rose and kitchen/bathroom mixers.
Inverter air-conditioners in all 3 bedrooms.
Energy efficient lighting (globes) throughout.
Open design maximises light and cross ventilation reducing need for use of lighting and airconditioning during the day.

Water
1000 litre Lysaght rainwater tank.
Plumbing is designed for greywater system, but currently not implemented.
Water efficient taps and showerheads.
Plumbing connect to town water supply.

Other
Lightweight, low mass materials have been used that respond quickly to changes in temperature such as steel portal frames and roof, and timber (stud frames, walls and floors).
Another advantage of simple steel and timber construction was the ability to prefabricate the structural elements on the mainland and assemble on site.
All materials recyclable.
Minimal disturbance to the site.
Designed to minimise material consumption and labour.