SUMMARY
o This is a new family house for a couple and their 2 young children that replaces an old cottage in Smith St.

o The idea for this house has a central courtyard, which faces north for winter sunshine, and gives great privacy to the occupants.

o Every room faces onto the courtyard and thus gets good light and ventilation.

o The front elevation of the house is a single storey to match the streetscape, but inside there are two storeys facing the courtyard with timber sunshades.

o The house is exceptionally well insulated and has very high thermal mass with concrete floors on both levels and all internal walls in Hebel block to maximise passive heating.

o Passive summer cooling is achieved through every room having having cross ventilation with windows and doors on 2 sides for cross ventilation and the stair is used for diurnal cooling (using cool night air to bring "coolth" into the house for the next day).

o The roof water is cleaned and stored in a water tank buried beneath the carport to provide all the water for the gardens and external uses.

o The house has been built from low environmental impact materials, using concrete floors and walls instead of brick and terracotta tile, all the timber being either recycled (flooring) or from plantation sources (all structure and external shading battens.

o To assist energy saving all the appliances are 5 star and all the lighting uses low energy T5 and T8 electronic Fluoro tubes, hidden in uplighting pelmets.

o The internal finishes were specially chosen for their low outgassing (e.g. Aalto low VOC paint).

INTRODUCTION
This is a new family house for a couple and their 2 young children that replaces an old cottage in Smith St. The site is relatively narrow running east west, and the old house, like all the other houses in the street, was a "box" with a rear garden, with rooms stacked around an internal corridor, no access to north light, dark and not well ventilated. By contrast the idea for this house has a central courtyard, which faces north for winter sunshine, and gives great privacy to the occupants. The front elevation of the house is a single storey to match the streetscape, but inside there are two storeys facing the courtyard with timber sunshades.

DESIGN CONCEPT
The house is part of a continuing exploration of courtyard housing by Environa Studio to provide both high environmental performance and good internal amenity and privacy on very small land areas. In order in order to maximise northern sun and light from the side boundary the new house has a courtyard form which differs markedly form the other 'box' style houses in the street. The house has a single storey scale to the front and back streets to fit the streetscape, with a private 2 storey courtyard at the centre. Every room faces onto the courtyard and thus has a view and gets good light and ventilation (see below). The house has living areas on the lower level and bedrooms on the upper level to utilise diurnal temperature changes in winter.

THE COURTYARD
The house has a courtyard form in order to maximise northern sun and light from the north side boundary, providing a totally private living at the centre of the house. The area of the site taken by the house footprint is reduced from the original house (75% to 68%) by the development of 3 courts that are all soft landscaped to ensure maximum water absorption. The courtyard has bamboo for height and some select plants around some well chosen sandstone rocks (inspired by Japanese gardens) for horizontal effect.

STREETSCAPE
The single storey form at the front and rear allows the house to match the streetscape and continue the low cottage scale of the street and the area and to ensure that the privacy to adjacent house is continued. The front fence has been deleted and replaced with a garden open to the street. Privacy is achieved through a layering of the stone wall to the entry steps and a screen to the front porch. This "public garden" has a spectacular maple tree to give shade to the west facing windows in summer. The form of the veranda continues the tradition of these transitional spaces along the street, and the materials to the exterior are muted to reduce its visual impact.

THE SECTION
The roof slopes steeply to the south over the centre section to allow equity of sun access to the adjacent house to the south. The house form is derived directly from passive heating and cooling considerations. Every room faces onto the courtyard and thus gets good light and ventilation. All the ground floor rooms have multiple sliding doors that open to the courtyard.

THERMAL COMFORT: PASSIVE COOLING
The house is exceptionally well insulated and has very high thermal mass with concrete floors on both levels and all internal walls in Hebel block. Passive summer cooling is achieved through every room having having cross ventilation with windows and doors on 2 sides for cross ventilation and the stair is used for diurnal cooling (using cool night air to bring "coolth" into the house for the next day). The basement is use as a cold store, with cooler air being drawn into the house from this store by mechanical ventilation.

THERMAL COMFORT: PASSIVE HEATING
The site is not ideal for a climate designed (passive solar) house as the access to north sun from the side boundary to a narrow site. A further complication is a large 2 storey house built on that boundary. By facing a centre courtyard to this side boundary the house can maximum passive winter solar heating whilst maintaining complete privacy. The majority of glazing faces north with some east and west at the ends of the courtyard. All the glazing on both levels is fitted with timber shading battens. The house was rated according to the NatHERS programme prior to construction, and was rated at 5 stars.

ELECTRICITY AND LIGHTING
All the lighting to the habitable rooms is by dimmable low energy T5 and T8 electronic Fluorescent tubes, hidden in purpose designed uplighting pelmets. These direct light to the ceilings which act as a reflector to the spaces below giving a more even and comfortable light at one third of the energy expenditure for conventional incandescent lights. The laundry and bathrooms are fitted with recessed PL lights, and the only non fluorescent lights are some halogen lights over the long dining table (for mood effect). The total electrical energy use for the house has been audited for the first year of use and shows it to be about 114 kWh/day which is 40% of average house use. The house is connected to Green power for electricity and gas for all cooking and heating which is the optimum achievable in suburbia without PV panels.

POWER AND ELECTRICS
All the appliances are 5 star: the fridge,, washing machine and dishwasher. The house has a service yard which has a permanent drying line (out of site of the living areas and courtyard) which removes the need for a clothes dryer. The house is fitted with a C-Bus electrical system to control all the lighting and environmental controls that allows for for low usage and automatic cut off to reduce energy use.

GREEN MATERIALS 1
This project continues an interest of Environa Studio in 'eco-tech' architecture using standard construction materials in unusual ways to achieve a highly wrought structure that has a high environmental performance. The floors are both in concrete, supported on Hebel blocks for the exterior skin to provide a tough acoustic skin, and a steel frame around the courtyard to provide cost efficient openings for the large doors and windows, which are a mixture of standard aluminium frames on the lower level for durability and timber on the upper level for lower energy impact. A preliminary study of the total embodied energy in the materials used (using Bluescope LISA) shows that the total embodied energy is about 65% of the materials used to construct a house of similar size in standard project house construction.

GREEN MATERIALS 2
Environmental impact
The house has been built from low energy/low environmental impact materials, using concrete for all floors and walls instead of brick, timber and terracotta tile. All the timber being either recycled (flooring) or from plantation sources (all structure and external shading battens. Consideration is given to ensuring that materials are considered for their environmental impact:
o all the internal timbers (floors, stairs and balustrades) are from recycled timber
o all the structure and external timbers (external shading battens) are from plantation sources

GREEN MATERIALS 3
Air quality
All the internal finishes were specially chosen for their low outgassing:
o all timber floors treated with a pure tung oil (Organoil) and no polyurethane floor finishes
o low VOC paint used for all internal areas (Aalto low VOC).
o concrete floor and wall tiles used throughout (nil outgassing and lower energy demand than ceramics)

Recycling
The house has been designed so that maximum recycling is possible:
o all the structure in concrete and Hebel are capable of re-crushing for reuse
o all the window/door joinery and general joinery has been fixed such that it can be removed for recycling without interruption to the structure generally

WATER CYCLE
All the fittings in the house are the lowest demand fittings available at present: using AAA rated fittings for basins and sinks (5L/min) and showers (9L/min) and 6/3 flush toilets. The roof water is cleaned through a first flush diverter and filters before being stored in a water tank buried beneath the carport. Currently this provides all the water for the gardens and external uses, and is to be extended to the full house uses when legislation permits. This saves on stormwater going to the nearby beach and saves on fresh water demand.

WATER, WASTE + SERVICES
The house has a rear courtyard for services including an area for clothes drying. A small shed houses all the services for the house including the first flush diverter and water filters, the instantaneous gas booster for the hot water and the central vacuum system and the dedicated recycling area to assist in sorting and recycling of waste.

CREDITS
Owners: Tracey Mietzke and Manuel Talbert
Architect: Tone Wheeler of Environa Studio
Engineer: Matthew O'hearn/O'hearn consulting
Landscape: Lester Landscape Design
Builder: Manuel Talbert/Northern Design + Building
Address: 22 Smith St Manly
Dates: Design 2001-2, Construction 2002-3