Residential Notes: A new building located on a rural property approximately 10km south of Murrumbateman on the Barton Highway. This project was conceived as a retirement house for the owners, but also forms the centre piece of a working farm. The brief placed environmental sustainability as a critical element of design. Difficult siting issues led to incorporation of active solar technology for space heating. Spectacular views over surrounding farmland and Brindabellas were an important factor in many of the design and siting decisions. The mature garden to the south was also a major point of reference.
Architect: Peter Overton – TT Architecture
Water Harvesting: The farm on which the house is situated has large reserves of stored water in existing tanks and dams which provide for all potable, service and irrigation demands. Water from the roof is drained onto the ground and picked up by subsoil drains for site irrigation purposes. Eaves gutters were not fitted due to likelihood of blockage from nearby eucalypt trees. All sanitary drainage is treated on site by a septic system and discharged for in-ground dispersion.
External walls construction: Corefilled concrete blocks - Smart Masonry was chosen to enable dry laying of walls without need of a bricklayer. All external and most internal partition walls are made from 140 or 200 thick Smart Masonry. External walls are clad with a styrene-based render system (Exin) which is adhesive and mechanically fixed to the concrete substrate to form continuous reverse veneer walls. .
Internal walls: Most partition walls, other than some around bathroom areas, are made from the same core-filled concrete block as the external walls, mostly 140mm thick. Internal surfaces are finished with a light bagging mix to reduce wet trades content. Electrical and water services are routed through conduits laid into the block walls before core-filling. No ceramic was used for either floor or wall finishes as a method of reducing embodied energy and difficulty in cleaning.
Roof: Zincalume corrugated roof sheet with some Speed Deck on low-pitch verandah roofs. Surface is heat reflective to reduce summer cooling loads and insulated sarking is used throughout.
Floor: Floors are all site-formed concrete with monolithic finish and integrated colour pigment. Industrial urethane sealer is used over surface. No tiles are used in any location, thus reducing materials and embodied energy. Hydronic heating lines are laid into floor slab as distribution system for radiant heating. R1.0 extrudedstyrene used around full perimeter, 800mm wide and at all slab edges.
Windows: Split-frame aluminium windows with clear double glazing; tilt-and-turn opening casements generally. Selective coatings for improved heat retention are used on high-level windows. Electric opening motors on high-level clerestorey windows.
Electricity generation: Owners intend to add a photovoltaic array onto the roof of a nearby shed. Overshadowing from nearby trees presents problems for the available house roofs.
Heating & Cooling: The house is designed to make use of night-purge cooling with assistance from buoyancy driven flows. Large clerestorey windows are incorporated in the upper levels of all main rooms and allow cooler night air to flush through the house in large enough quantities to drop the structural temperature. Some parts of the house gain benefit from direct solar gain to passively heat the spaces, but for the most part, the house uses a large solar thermal plate array to collect solar energy and distribute it through the house via hydronic pipes in the floors. Storage for the system is provided by 2 x 3000 litre tanks which also provide service hot water. Back-up energy is from an LPG boiler. As well as extensive verandahs to reduce heating load, operable vertical shades are incorporated into the design on the south-west facade. Provision has been made to add vertical louvers to the north-east clerestorey windows if the need arises.
Water Heating: Approx. 28 sq.m. roof mounted Apricus evacuated tube collectors provide both service hot water and space heating water.
Appliances: Extensive use of low-energy flurescent light fittings, low-flow shower heads, front-loading washing machine, indoor and outdoor clothes lines, gas cooktops and ovens.
Landscape: An integrated landscape scheme has been designed and will be constructed over the next few years. The existing gardens to the south were retained during the course of construction, including a large eucalypt to the south-west of the main living area. A courtyard garden will be added to the north in the near future.
Additional notes: Design demonstrates use of active solar elements to overcome difficult site design issues which precluded conventional north-facing orientation for living rooms and main fenestration. Simple, structure-integrated finishes were used throughout to limit embodied energy and cost. Design reduces fire risk and should have a low maintenance requirement in the long-term.
Address: Climate Zone NATHERS 25 – Cool Temperate with around 100 days frost; some short but extremely hot periods over summer.
(August 2009) (
