“Living-Breathing House”
McRaewood Road, Clare, SA.
Geographical Location
The Clare Valley situated 90kms north of Adelaide has regions with altitudes ranging from 300 to over 500 metres above sea level. The climate is moderately continental, with cool to cold nights and warm to hot summer days. Rainfall is predominantly in winter - spring (June - September) with an annual average of around 630 millimetres. Generally dry summers make some irrigation desirable but also ensure a minimum of fungal diseases. Varied soil types throughout the valleys are another feature, ranging from red to brown grey over basement rock.
Site
The rural house site is located north of the old historic settlement of “Armagh” and the main township of Clare (33.5°S, 138.36°E). There are a number of Eucalyptus trees on the site which have been maintained as much as possible to also provide natural shading to the house. Native plants (which require less or minimal amount of water) are being revegetated to restore the condition before settlement. The total area of the site is approximately 9ha. The site has a gentle east-west slope with views to the north and west over “Jim Barry’s shiraz ‘Armagh’ vineyards were maintained.
Brief
The owners of the house, wanted to live in a self-sufficient compact house to satisfy a family of four with the main goal of creating an "ESD" (ecologically-sustainable development) house, which is self-sufficient for water, wastes and electricity; uses as much recycled material as possible without spoiling aesthetics or function; and makes best use of the site with minimal damage to it.
Design Solution
The designer has captured the essence of the Australian bush buildings with this project, complete with external sleepout and “outside” toilet. Iconic and familiar in form, the residence has a look and feel of aged buildings of a bygone era but is only 2 years old.
A further strong feature of the design is the attitude to ESD in the selection of building materials, the assembly and building by-products. The scheme follows the ‘timber and tin’ typology found in early Australian architecture; the use of corrugated iron for cladding and roofing is common, juxtaposed with timber and rammed earth walls. The logic of this type of construction has stood the test of time demonstrating sensitivity to the eco-efficiency of construction.
Care was taken to ensure that the structure used environmentally friendly materials and as the property was not serviced by either water or sewage services, appropriate products that offered low maintenance that did not have any chemical side effects, were researched thoroughly and finally selected.
The location for the building on the site was selected based on the considerations that it would allow for maximum northern exposure as well as catching the breeze for natural ventilation with minimum destruction to the site. This enabled prime northerly access and creates casual living area adjacent to the eastern bank. Views to the west & north overlooking the adjoining vineyards were maintained.
The stabilised rammed earth was recommended by the designer as it provided a compromise between mud brick, a low embodied energy material but has a natural look, and concrete, a more modern looking material but has a much higher embodied energy and a 'cold' look.
To help minimise the cost of rammed earth walls, concrete blocks were suggested initially (then changed to clay bricks for the construction drawings; then reverted back to original thought due to supply problems). These were used internally then rendered to compliment the external walls. Where framed walls were used, all are insulated with R2.5 “Air-Cell” insulation.
The 100mm polished concrete floors provide thermal mass and do not need tiles or other finishes. The roof structure used Hyspan LVL exposed roof beams and galvanised corrugated cladding as the ceiling lining to reduce ongoing painting maintenance and thereby minimizing out gassing from plasterboard products.
Whilst the site is not located in the bushfire zone, where possible the building was designed for bushfire conditions should a future need arise. Although aluminium windows have high embodied energy, they were selected for better fire resistance, improved energy efficiency and to minimise on-going maintenance.
In the main living areas Stegbar AT2000 windows (thermal break) were selected which feature an aluminium exterior with a western red cedar interior frame. Northern windows are glazed in “Pilkington Comfort Plus Grey” glass.
Whilst the footprint of the house was small the designer created the feeling spaciousness by providing raked ceilings the main living areas. To further reflect the ambiance of earlier colonial buildings galvanised corrugated sheeting was installed as the ceiling lining with R3 insulation batts between.
It was desirable that natural lighting be used wherever possible, even though a back-up power system was installed, it had not be used since the occupation of the house. To this end, the internal “study nook” gained natural lighting via a Velux rooflight above and indirect lighting through the glass block internal window.
Energy Efficiency
Passive heating and Solar Shading
Several passive solar design principles were incorporated into the house design with polished concrete north facing floors where these slabs have been cast onto the existing ground levels.
The rammed earth walls provide low embodied energy with high thermal mass and galvanised steel used for the external rear cladding. A fully insulated galvanised roof was used. Eaves overhangs were carefully calculated to protect the house from the summer sun and allow the winter sun to enter.
Supplementary heating & cooling
Wood grows & dies naturally on the property & is a renewable energy source as well as being greenhouse gas neutral. Heating is provided by an efficient slow combustion stove. The stove has been fitted with a water jacket around the flue to supplement the solar water heater in winter, however due to budget constraints this has yet to be connected.
- Stove heats the whole house
- Stove positioned centrally
- Doors & windows allow cross ventilation
- House uses only ceiling sweep fans as an aid in assisting with air circulation.
- The Owners have commented that during the 2005 summer whilst outside temperatures were nearing 40°C inside was a pleasant 25°C.
Insulation
Roof insulation to R3 levels
Frames walls to “rear” sleepout insulated to R2.5
Water & Waste Water Treatment
Blackwater treatment using a composting water-less WC whilst Greywater treatment utilizes a “reed bed” filtration system.
Rainwater Harvesting
Rain water is collected off the roof and piped to 2 water tanks positioned uphill and to the south-east of the house. The storage capacity of the tanks is 20,000 litres.
Renewable Electricity Generation
Solar Photovoltaic system with diesel-generator backup. It is interesting to note that a total of 1009kWh have been used during the construction and occupation of the house, of which only 49kWh have been derived using the back-up generator, which occurred only during the construction stage. The remainder has been generated “free” via the use of the photovoltaic panels.
Appliances
- “Edwards” Solar hot water
- Kitchen – small compact 2* rated refrigerator
- Bottled gas cooktop
- Lighting – compact fluorescent lamps used throughout
Material Selections
- External Walls – Rammed Earth generally
- Polished concrete slab on ground
- Galvanised corrugated cladding to “sleepout” and “wet areas”
- Stegbar AT2000 Aluminium windows
- Recycled timber doors
- Galvanised corrugated roof sheeting
- Recycled jarrah kitchen benchtop
- Recycled cypress pine bedrooms 1 & 2 flooring
- Exposed Hyspan LVL timber beams to Living area.
Conclusion
This house represents a good example of an autonomous house that is not grid connected. It is a single storey house with high mass, very good insulation, and correct window sizing. It incorporates a solar hot water system, a non grid-connected photovoltaic system, an environmentally friendly sewage disposal system, and rain water collection storage and reuse. Kitchen waste is composted. Clothes are dried on a clothes line. A vegetable garden and vineyard have been established. Whilst these ESD design features are now not unusual, what is different in this house is that they have been incorporated into a finely crafted building that was designed using a philosophical position that encompasses both the physical and metaphysical aspects of design.
Having lived in this house for approximately 2 years, the owners are pleased that they took Bill’s advice on design, site orientation and the technical aspects of sustainable design.
The occupants indicate that they are very satisfied with the quality of living in this house. Living in the 'bush' as well as being able to view and feel the outside all the time is an important aspect in this family. According to the occupants the house is quite comfortable during the year and confirms that the thermal effects of the design live up to their expectations with the house remaining warm in winter and cooler than the external temperatures in summer.
As stated earlier, they had commented, “During the 2005 summer whilst outside temperatures were nearing 40°C inside was a very pleasant 25°C”.