SUMMARY
o This project is for the 6 new townhouses at 121 - 12 3 Glenayr Avenue, Bondi.

o Unlike the apartment buildings on either side the concept here is for 6 "terrace" houses, each designed as an individual house with its own address, access from underground car parking and with each house having access to ground and to a roof garden.

o This is the revival of a well known traditional Sydney housing prototype in a contemporary form that responds to the particular environmental conditions.

o Each house is oriented to the north to maximise winter sunlight and to utilise cooling north-east breezes for cross-ventilation.

o The building geometry is angled to be oriented north along one side of the property and is kinked to align with the boundary on the southern side.

o The building's form is a response to the sun conditions: a steeply sloping north roof allows sunlight deep into the house as far as the rear stair, providing light and sun throughout the terrace house.

o The butterfly roof form has a short north oriented section for the provision of solar water heaters.

o All six townhouses achieve a NatHERs rating of 5 stars.

o The houses rely primarily on passive means of winter heating with the use of solar gain through the north facing glass to every room.

o The houses rely solely on passive cooling (no air conditioning) with the use of maximum ventilation in summer together with the thermal mass.

o A complete water system provides for the capture and use and reuse of 100% of rainwater falling on the site making it totally water self sufficient.

o The building is to be built from low energy/high life cycle benefit materials.

o Low VOC materials, paints and glues are specified throughout.

o The north end of the roof garden of each house has a north sloping roof fitted with photovoltaic cells for electricity generation. These are grid connected and are sized to supply about 50% of each houses' demand.

INTRODUCTION
This project is for the 6 new townhouses at 121 - 12 3 Glenayr Avenue, Bondi. The existing site has two single storey Federation houses on separate allotments which have been substantially altered and are now dilapidated in an area where the predominant housing form is multiunit housing. Either side are apartment buildings: to the north are 4 dating from the 1930's, identical to that featured on the 2003 TV show "The Block", and to the south are 7 small and complex apartments with basement parking, built within the last 10 years.

SITE ANALYSIS
The site's length allows for a series of houses to be designed which are cranked in the cross-site axis to engage a true north orientation for the living areas of the house. The building footprint is approximately 50% of the site, allowing for private open spaces to the north of each terrace and communal open space on the south side for access.

DESIGN CONCEPT
Unlike the apartment buildings on either side the concept here is for 6 "terrace" houses, each designed as an individual house with its own address, access from underground car parking and with each house having access to ground and to a roof garden. This is the revival of a well known traditional Sydney housing prototype in a contemporary form that responds to the particular environmental conditions. The design intention is to create terrace houses rather than apartments, and for each owner to have an identifiably separate townhouse.

BUILT FORM 1
The built form follows the tradition of Sydney's terrace housing with each house being similar one sharing a party wall on both sides. The overlay of environmental issues creates a built form with a change in geometry from the traditional house, using a cranked design with the living oriented due north and the service areas and bedrooms aligned to the geometry of the site. In this way, each house turns away from the busy Glenayr Avenue and is oriented to a private north facing outdoor space.

BUILT FORM 2
The form of the development is dictated by considerations of environmentally sustainable design. Each house is oriented to the north to maximise winter sunlight and to utilise cooling north-east breezes for cross-ventilation. The building geometry is angled to be oriented north along one side of the property and is kinked to align with the boundary on the southern side. The entries to the houses are highlighted by the use of horizontal zinc metal cladding and vertical windows in contrast to the bulk of the building which is in rendered concrete. In this way a number of diverse materials and textures are colours are used on the three visible facade of the house to increase its diversity visually from the street.

STREETSCAPE
The built form takes its cues from the adjacent buildings providing a singular form for the bulk of the building, although this is clearly visually broken into smaller elements indicating each townhouse. Overall the mass and height of adjacent buildings are maintained whilst a dramatic roof highlighting the use of north facing sunlight into the townhouses gives a strong roof form to the buildings. This roof pitch takes its cues from the relatively steep roofs on the surrounding 1930s and 1940s apartments. The facade shows the crank in the design allowing for the habitable areas to face north with entry and private areas to the south aligning to the orthogonal grid of the site. The front elevation is further highlighted by the use of verandas and roof terraces which are detailed in horizontal timber materials in contrast to the flat walls. The built form has the appearance from the street of a two-storey building with a dominant roof form which mirrors, in a contemporary way, the characteristics of the surrounding buildings.

SECTION 1
The building's form is a response to the sun conditions: a steeply sloping north roof allows sunlight deep into the house as far as the rear stair, providing light and sun throughout the terrace house. The butterfly roof form has a short north oriented section for the provision of solar water heaters. This roof sits over the stair and provides a "solar chimney tower" for summer cooling. The north end of the roof garden of each house has a north sloping roof fitted with photovoltaic cells for electricity generation.

SECTION 2
The townhouses have 3 levels with an internal staircase leading to an open roof garden. The section allows for maximum solar penetration to the house through the north oriented glass through the raked skillion skylight at the top of the house. In this way, the townhouses take advantage of the site's attributes of having a long east-west axis allowing for maximum north space and being able to separate the north facing private open space and habitable room windows from the service areas, communal areas and access on the south side.

PLAN LEVEL 1
The townhouses are sited to the centre of the site, with pedestrian access provided on the south side to 6 clearly identified entries to each of the houses. The private open space at ground level is located to be able to be an extension of the dwelling for relaxation, dining and entertainment and takes advantage of the north orientation of each house. This north facing courtyard increases the achievement of comfortable year round use since the deciduous tree allows for maximum sunlight penetration to the outdoor space and house whilst in summer the tree and landscaping provides shading to the outdoor space. The continuum of indoor and outdoor space throughout the house allows for cross ventilation through the house without the loss of acoustic privacy to adjacent houses.

PLAN LEVEL 2
The front townhouse has windows facing the street and provides overlooking to improve personal safety and minimise the potential for crime and fear of crime on the street frontage. The remaining terrace houses are oriented away from Glenayr Avenue at 45 degrees which creates the illusion of greater distance between neighbouring buildings and hence a reduction in privacy.

PLAN LEVEL 3
The site offers little in the way of views except from the front townhouse into the street and so concentrates on provide private north facing outdoor space and a north facing roof garden. Each townhouse uses the traditional party wall extended from the house to provide visual privacy between houses. The orientation of the living areas at a 45 degree diagonal from the geometry of the site allows a minimum distance of 9 metres between any habitable area in the townhouses and the side windows of the adjacent flats. In this way, direct views between habitable and private open spaces to the adjacent flats are minimised, increasing the sense of looking away from the adjacent flats.

CAR PARKING
The existing fall to the north is utilised to provide a car entrance at the lowest point on the site (where there already is a street crossover for the single house) into a underground garage. There is an individual car parking spaces for each house and as the car parking is under each house it both allows direct internal access to each house and allows for substantial areas of soft landscape planting. There is only one car per house (as opposed to Council's requirement for 2) as it was argued successfully at Council that it's proximity to public transport should reduce the emphasis on private car spaces (it is within 650 - 800 metres of three separate transport modes).

THERMAL COMFORT: BUILDING ENVELOPE
All six townhouses achieve a NatHERs rating of 5 stars. All townhouses have a maximum area of glazing facing north, are heavily insulated to R3.0 in the roofs are 1.5 in the walls and have considerable internal thermal mass with concrete walls and concrete floors used through. All north facing and west facing glazing is fully shaded for summer sun penetration whilst allowing winter sun for passive solar heating.

THERMAL COMFORT: PASSIVE HEATING
The houses rely primarily on passive means of winter heating with the use of solar gain through the north facing glass to every room and the very high thermal mass of the internal concrete walls and floors. The floors are finished as polished concrete to enhance the solar gain into the thermal mass. Supplementary gas heating only is provided to the living areas of the house.

THERMAL COMFORT: PASSIVE COOLING
The houses rely solely on passive cooling (no air conditioning) with the use of maximum ventilation in summer together with the thermal mass. The summer cooling is provided by 3 means; (a) cross ventilation, (b) rising stack ventilation using the stairs and an exhaust at the top of the stair void and (c) diurnal cooling with the use of mechanically assisted ventilation at night to cool the building down and provide coolth to the thermal mass.

LIGHTING
Natural lighting
All rooms are lit naturally, with large areas of glass to the north whilst the size of windows to the rear is reduced to allow for daylight and cross ventilation but minimising overlooking to the adjacent buildings.

Artificial lighting
High efficiency fluorescent lighting is used throughout the townhouses with the use of T5 electronic lamps used in pelmets in every habitable room and the use of compact fluorescent lamps in down lights in all service rooms.

POWER
Supply
The north end of the roof garden of each house has a north sloping roof fitted with photovoltaic cells for electricity generation. These are grid connected and are sized to supply about 50% of each houses' demand.

Demand
Five-star rated appliances are used throughout, including the dishwashers, washing machines and fixed appliances. No clothes dryer is fitted as all houses have access to a roof garden which provides for naturally aired clothes drying.

Water heating
Each townhouse is provided with an individual solar water heating system: the panels are located on the top of the "solar chimney" roof, with a remote tank to reduce the visual impact, boosted by an instantaneous gas heater.

WATER CYCLE
Demand side management
Water consumption is minimised by the use of AAA rated devices throughout the houses, 6/3 flush WC's and by landscaping with a minimum water requirement and the use of mulching all irrigated landscaped area.

Supply
Consultant Terry Lustig, designed a complete water system for this development. In brief the proposal is for the capture of 100% of rainwater falling on the site. The roof water is channelled to rainwater tanks in the basement, which is the source of fresh water for the houses. The remaining site water is collected and added to the grey water or is detained on site prior to being released into the Council's stormwater system. The grey water generated by each house is stored in the basement, where it is cleaned and reused through the toilets and car washing facilities and for landscape use prior to being discharged to the sewer.

GREEN MATERIALS
Life Cycle considerations
The building is to be built from low energy/high life cycle benefit materials. Concrete is used for thermal mass in the floors and walls (rather than higher energy masonry). The transmission of noise between dwellings is minimised by this use concrete, having a minimum STC of 53, and the driveway and parking areas are located below ground ensure minimum acoustic intrusion into the houses.

Air Quality considerations
Low VOC materials, paints and glues are specified throughout. This increases the air quality for workers during construction and for the inhabitants.

WASTE MANAGEMENT + RECYCLING
A separate area for garbage bins and recycling bins is provided in the car parking area allowing for storage of bins prior to collection from the street to be kept to a visually discreet and secure area. A separate area is provided at the base of the stair in the car parking area for each house for the temporary storage of waste that will allow for the separation of materials. The houses are not fitted with in-sink waste disposal systems.

CREDITS
Owner: Paul Oosterhuis
Architect: Tone Wheeler of Environa Studio
Structural Engineer: Matthew O'hearn/O'hearn consulting
Hydraulic Engineer: Terry Lustig
Landscape: Material/Jim Osborne
Address: 121-3 Glenayr Street Bondi
Dates: Design 2003, Construction 2005