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Bundeena House


House  /  Completed
The house lies below street level to retain views over it from neighbouring houses. Conceived as a treehouse with platforms taking shelter amongst the tree canopies, the volume floats over the terrain to minimise site disturbance and maximise daylight access and views.

The journey through the site starts at the heavy, partially cantilevered, off-form concrete garage, proceeds over rock ledges between twisted fig trees to the house. Inside, the envelope gradually opens up to reveal the tree canopy above and distant views beyond. The culmination is the narrow, fragile point at the end of the deck where you are almost completely suspended in the sky.

The plan is a simple rectangle and a right-angle triangle, forming two separate roofs and two split-level living areas beneath. The height and angle of the roofs create a complex and dynamic internal space emphasized by using a single material, birch ply, for walls and ceiling.

These floating roofs allow views of the surrounding trees and dappled light to enter the house and allow views through the house as you descend from the street.

Traditional beachside holiday-home materials are employed throughout the project with steel framing, cement sheet external walls, metal roofing, plywood internal linings, and timber floors. The simplicity of the materials is enhanced by the precision of the construction and detailing, showing through the close collaboration between architect and builder.

The close relationship between indoor and outdoor spaces is a constant reminder of where the house sits, while a compact and open-plan floor plan facilitates interactions between the family members. The space is permeated by a feeling of spaciousness throughout with the play of roof heights, split-levels, simple materials and light.

The house sits on the western slope of a wooded hill. Despite the orientation, the heat-load is minimised due to the existing mature trees and passive solar design strategies such as large eaves and overhangs to northern and western facades, high performance glazing, and operable openings for cross ventilation. The roof, the main source of heat gain, is heavily insulated.

Natural ventilation is facilitated by a combination of high- and low-level windows. Small screened openings and large sliding low-e glazed doors allow the residents to control the amount of natural ventilation.

A 6.8 kW solar system powers an electrical heat-pump which regulates the water temperatures for the hot and cold (4°C) water tanks. Hot water is pumped through to the hydronic radiators for heating in winter; and cold-water tank cools the air before being ducted to the two living areas in summer. The system is currently energy positive and is expected to remain so even with four full-time occupants.

The bedrooms do not require cooling as they are on the lower level, behind the hill, and have natural cross ventilation. A vast amount of daylight enters the building, eliminating the need for artificial lighting during the day.

The project was initially thought of as an investment and later as a week-ender for the client and his family of four. However, during construction, the family fell in love with this little coastal village and decided to live there permanently.

The site was one of last built upon lots in the subdivision of a former Uniting Church campsite on the western side of the steep hill behind Bundeena Beach in the Royal National Park.

The owner, who worked as a carpenter on the construction of the first four houses in the original subdivision in 2007, was given the opportunity to return to Bundeena and purchase this challenging block 10 years later.

The owner’s passion for the project is clear from the quality of the construction and the investment in the long-term performance of the building. Incorporating passive and active sustainable design strategies from the project’s conception.

Significant challenges were overcome by the structural engineer to design a steel structure with few internal walls, clerestory windows and cantilevered balconies.

This beautifully built house is the product of a relatively small budget but a huge investment of time, care and commitment by the owner-builder.


 Ian Gribble
 186 mq
 Erik Rudolfsson, Tom Pinyon, Lester Fei, Joseph Alliker
 Join Constructions
 Ian Frankland, ITF Cabinet Making & Joinery. Adam Denham & Ian Gribble, Join Constructions. Structural Engineers, Van der Meer Consulting
 Michael Nicholson


We are architects who believe you can improve the way people live through good design. We think that good design is functional, rational, sustainable, adaptable, innovative and joyful.

We enjoy the learning process and invest time in new building types. Current experience includes housing, apartments, offices, boarding houses, dental and medical centres, nightclubs and bars, interior fit-outs, child care, aged care, furniture, chapel and mortuary.


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