Australian firm Lara Calder Architecture designed ‘Eco House’ which was awarded first prize last year in the Future Competition 2008 held by Australian Green.

Their design concept was that of a temporary shelter.

From the architects:

‘The primary inspiration for our design is the concept of temporal shelter, strongly informed by an indigenous response to the land and climate; an acknowledgement that upward of 40,000 years of occupation of the land resulted in little or no impact on the environment. The aboriginal shelter is referenced as is the more contemporary tent and fly; the idea of touching the ground lightly, of respecting the land. The design addresses wider social issues including the perceived need for excessive space and services. Also addressed is the idea of a primary communal living space, a space that encourages social interaction, compromise and understanding. Too often in contemporary residential living environments, the occupants have no need to share or interact, because houses offer excessive latent space that is only used intermittently.

Context
This house is an intelligent response providing a suitable and sustainable building form for suburban development in western metropolitan Sydney. It offers an alternative to resource-hungry low-cost project homes. In its intended suburban context, car provision has not been given a high priority. We believe that a major re-evaluation of private transport will need to be addressed in the future, and that metropolitan areas will come to rely on efficient public transport networks. Our design can accommodate a car (in either a covered or uncovered space), however we believe that a realistic alternative for suburbs of the future could be community carpools where cars are hired on an as-needed basis. Self-sufficiency for water and energy is an ideal for this design however we expect that the house will have public resource infrastructure (power, gas, water) available. The wider issue of neighborhood-scale resource management (refuse disposal, sewage treatment, water management etc) is not specifically addressed here however, we believe that housing of the future will necessarily include “end to end” solutions from individual housing through neighborhood, suburb and city scales.

Construction
The primary structure is six timber portals. Over these portals a high-tech fabric ‘fly’ is suspended. In each portal bay pre-fabricated units are suspended and configured to produce a flexible interior living environment. The prefabricated pods have weatherproof roof, walls and floors, however the primary weather barrier is the fabric canopy.

Sustainability of Materials
Materials are generally selected for their low embodied energy. The structure necessarily includes some steel and plastic-based elements, however these are minimized in favor of predominantly timber, cement and plaster products. The portals are laminated timber pinned to concrete footings. The fabric is a PVC waterproof membrane. The prefabricated units have a rigid steel outer frame with timber-frame infill panels to walls and roof. The floor is a concrete slab panel. The units are clad in painted fiber-cement with a liquid membrane roof. Window and door frames are timber. Double-glazing is used throughout the house.

Passive Solar Design
A connectedness with the outdoors is throughout the year is a feature of Sydney’s climate and a key consideration in the design of this house. North window overhangs are configured to admit low angle winter sun and shade from summer sun. The insulated concrete pod floors provide thermal mass. Wide opening doors on both levels acknowledge the benign nature of Sydney’s climate while smaller south-facing windows facilitate cross ventilation and the necessary ‘relief valve’ to combat over-heating in summer. All windows and doors are double-glazed. Windows are generally awning type allowing for good sealing when closed and to act as large louvres when open. Fabric blinds are provided for additional thermal comfort and to secure warm ambient temperatures on cool nights. Our expectation is that the design will not require complicated intervention by the occupants to enjoy the passive solar benefits of the house.

Energy Efficiency
While energy self-sufficiency is an ideal, we expect that the house will have an external energy supplies available. In our suburban context we propose a grid-connected electrical supply (using photovoltaic cells on the roof) and a gas supply.
The design intends for the passive solar design to take care of most of the space heating requirements. There may be occasions where this will need to be supplemented. We propose a simple flueless open fire (burning denatured ethanol) located in the main living space. A simple fan and duct system is proposed to redistribute warm air as required.
Hot water will be provided by a gas-boosted solar hot water storage cylinder. Solar panels will be roof-mounted (adjacent to the photovoltaic cells) and the water cylinder is located on the south side of the house.
No air-conditioning is proposed for the house. Cooling will be provided by ceiling fans, cross breezes and the use of the thermal mass in the floor.
Low energy fluorescent lighting is proposed throughout the house.
Gas cooking appliances (oven and hob) and high efficiency whitegoods are proposed. It is expected that most clothes drying can be accomplished with a clothesline and by using available rain-sheltered breezeways beneath the fabric roof.
High insulation levels are a key feature of the design. The pods are fully insulated and all openings are double-glazed.

Water Management
The primary objective is to significantly reduce the demand for potable water. The design anticipates a municipal potable water supply supplemented by non-potable stored water and on-site waste water treatment. There is no proposal to treat sewage on site; it is anticipated that suburb-scale black water drainage infrastructure will exist.
The fabric roof is provided with a barge/guttering system to direct the water to concrete storage tanks in the ground between the portal footings. There are four tanks assigned to rainwater collection with a total capacity of approximately 30,000 liters. The stored rainwater is used for laundering and exterior uses. Overflows from the raintanks could be directed to a neighborhood collection and reuse system for irrigating public areas, parks etc.
Wastewater from showers and basins is collected and treated in the fifth tank and stored for toilet flushing only. Storage is small capacity due to the requirement for fast cycling of this water.
The primary objective for the site is to maximize permeable surface area to allow dispersal of stormwater in the most natural way; water will be managed on site with a detention swale draining to a neighborhood stormwater management system. Any trafficable areas on site are provided using a grass-permeable paver.

Waste Management
In a suburban context, we would expect that the site would be serviced by a municipal refuse disposal and recycling program.
Waste management during construction is addressed by factory prefabrication of the elements in the proposal. It is expected that most of the above-ground components of the house can be delivered by a medium-sized truck. It is expected that several key elements (trusses, steel module frames, windows and doors etc) can be reused.

Affordability and Aesthetics
The scale of the house is modest at 164 sq m, the emphasis is on efficient planning and provision of one multi-functional living space. The bedrooms are big enough to contain ancillary uses (eg a study area). In Sydney’s climate, it is expected that for much of the year, the outdoor spaces can be used as additional rooms.
Factory mass production will assist in controlling the construction cost which must fall below $3,000 per sq m. While many of the proposed building materials are modest, expenditure is applied in areas where environmental performance is critical (eg glazing, solar systems).
The aesthetic is the simple shelter overlaid with some extremely contemporary componentry juxtaposed with familiar building elements. A modernist ambition to allow form to follow function has led to a building we believe is an appropriate image for a house of the future.

Climatic Fit
Sydney is a temperate climate: Although there are four distinct seasons, much of the year conditions are suitable for human comfort. The design response for this building utilizes passive solar principles (including provision of thermal mass), good insulation (including window and door drapes), good convective ventilation and cross ventilation.

Compliance
The house is intended for a suburban western Sydney context. The scale of the dwelling is considered to be appropriate for a regular-shaped 500sq m block with a larger setback from the north boundary and minimal setbacks on all other boundaries. A two story structure is considered to be appropriate scale for suburban development and falls within current guidelines for most existing council DCP’s. Addressing the need for better land utilization as part of the development guidelines by local authorities is a separate issue. We believe the prototype we have shown here could easily be adapted for a more compact footprint and/or a three-story structure.’

Further information: www.laracalderarchitect.com.au.