Fun Haus

The clients provided a hand drawn mind map of their values, passions and interests including connection to nature, social connection and mathematical patterns. They wanted to construct a home which could house at least 5 people and be flexible to evolving household arrangements. They had key interests in durable, sustainable design which maximised landscape.

The existing cottage to the main street frontage was in a heritage conservation area and therefore no new additions could be seen from the main street. Additionally, the compact 117m2 site and neighbouring development patterns restricted the building orientation and arrangement.

The site has a heritage sewer running below it. The dwelling needed to not impact the sewer zone of influence which essentially meant the dwelling was engineered to sits on stilts and the ground could hypothetically be removed from below. This greatly increased the cost and complexity of construction.

Another challenge was delays and cost increases in construction due to COVID19.

Due to efficient planning, the 117m2 site area is able to house 6 people. Four in the primary dwelling and two in the secondary dwelling. This gives the site a density of 1 person / 19m2, a stark contrast compared with Greater Sydney's average density of 1 person / 77m2.

Unnecessary luxuries such as large bathrooms, bedrooms and laundry were efficiently incorporated into the floor plan to maximise the living, working and courtyard spaces with all habitable rooms having a relationship with the private courtyard. The upstairs of the primary dwelling is designed so the space can be divided into 3 rooms when the family expands.

The density of the site is complimented by changes in texture and tone which delineate spaces - giving the dwellings multiple different personalities and places of respite. This way, Fun Haus allows the clients to be in close proximity to each other to share meals, interests, relaxation and work whilst also providing moments of privacy, challenging preconceptions of what can be achieved on a small site. Many moments of 'fun; were incorporated into the design, including monkey bars, a fish pond, a space for chickens and mathematical patterns in the ceiling.

The separation of the design into a primary and secondary dwelling, with a maximised central courtyard, means both dwellings have greater access to light, ventilation and landscape outlooks. The courtyard acts as a place for interaction between the dwellings but also as privacy depending how the occupants choose to engage with it. The dual access site and flexibility of the design greatly increases not only the use of the site but the financial viability of the construction. With the owners being able to offset their living costs by renting out the secondary dwelling in the future, adding more available housing stock to Inner City Sydney. .

The rear dwelling frontage is to a lane consisting of high rear fences and garage doors. The secondary dwelling provides a more engaging frontage to the lane with recycled sliding timber screens and a balcony in which a dialogue can commence between the lane and dwelling in its various forms. Developing the rear of the site as a dwelling means the lane becomes more interactive for pedestrians and residents rather than being a corridor for cars.

Sustainability is at the centre of our practice at ASA, as well as a high priority for the clients. The Life Cycle Assessment completed for this project revealed that the project has 33% lower embodied carbon than a typical Built-As-Usual new Australian dwelling. The 4.4kW solar system reduced the total embodied and operational carbon impact by 77% over its predicted lifespan. It is estimated 4589kWh of electricity will be consumed per year with the solar system producing 5328kWh per year. This means that the building is considered to be 'net zero' in respects to operational energy use. The building is 100% electric.

Due to the project being designed to the Passive House standard the home is adaptive to a changing climate. The high airtightness, heat recovery ventilation and mechanical ventilation means the house can operate with extremely low energy use during events of extreme heat. Filtration in the HRV means that far less air pollution from cars and bushfire enters the home. In addition, the high performance glazing, high insulation values and reduction of thermal bridging mean the building remains at a more consistent temperature. The construction achieved an airtightness of 0.75@50PA, passing the EnerPHit standard.

Roofing and cladding to the two dwellings is corrugated Colorbond steel. Despite the high embodied energy in steel, it is Australian sourced, reducing travel emissions and is extremely durable, requiring no maintenance. The ground floor concrete for both dwellings is Holcim ECOPact offering 70% reduced carbon emission from a standard concrete slab. Timber structural elements were favoured over steel to reduce embodied energy and thermal bridging.

Recycled materials utilised in the project include: recycled external hardwood battens from existing dwelling and reusing the existing floorboards. Partial elements of the existing dwelling which were adequate such as the boundary brick walls and front porch slab were retained and expressed. With new or replacement materials only filling in where absolutely required.

The existing back yard was highly concreted and overgrown with weeds and a non-native tree specie. The small footprint of the two dwellings enables the project to have as much permeable landscape as possible as well as enables all habitable spaces to experience the maximised central courtyard. A new native tree with large canopy cover is included in the courtyard. In conjunction with a pond with native fish and aquatic plants, and plants climbing the 6000L water tanks - these strategies promote biodiversity and shading on the tight urban site.