Co-housing offers a return to a more integrated and social living environment, with lower capital cost and energy use. Architect Andrew Benn and his mother Suzanne test the concept in Sydney. Text Suzanne Benn and Andrew Benn, Photography Katherine Lu and Tom Ferguson

Apart from the dividing courtyard wall, the two houses look like one.

With housing affordability now a major policy issue for our cities, and the need for sustainable housing models, architects and clients are searching for innovative solutions. A further dimension affecting housing is the changing makeup of households, with single-person households on the rise. The social isolation of traditional suburbia, combined with a growing interest in the sharing economy, guides us toward more collaborative paradigms for urban living.

The original Victorian terrace house planning was reversed
to connect the living room to the exterior and conceal bathrooms centrally.

One of these trends is co-housing. Developing at scale in Europe and America, it remains a largely untested concept in Australasia. Co-housers could be friends struggling to afford a first home, intergenerational families, or downsizers wanting to unlock equity for their retirement and live close to friends or family. Co-housers typically enjoy more privacy and independence than flatmates and each household in the group owns or rents a defined space. It differs from duplex or multi-unit housing in that more of the space is shared, enabling more efficient use of land. It is similar in principle to ‘granny flat’ development but less restrictive, allowing for more varied and flexible household groupings.

Double-height volume in the centre of each house increases the feeling of space.

An example project developed by Benn and Penna Architects involves significant alterations and additions to two existing Victorian-era workers’ cottages in the inner Sydney suburb of Balmain. Each of the properties is owned by different generations of the same family – architect Andrew Benn and his mother, Suzanne Benn – but together they form a united pair capable of supporting both the interconnectedness and independence of each family.

The main bedroom of house two has multiple layers for sun
control and screening.

Winner of a NSW Architecture Award in 2014, the cottages have been renovated as a flexible family complex, designed to enable interaction across some shared spaces, while maintaining the houses as individual units.

Semi-open book shelves and exterior louvres in the upstairs study, are strategies employed to
borrow light and create privacy. House two.

Incorporated into the design is a self-contained unit that can be utilised by other members of the family or possibly, in years to come, by a carer. The cottages are a case study for how co-housing can reduce living costs and create an improved sense of community. On a larger scale, such arrangements could create more compact, sustainable cities. With an overall site area of just 250 square metres, the design had to provide sun, outlook and a sense of interconnectedness, while protecting privacy between households. Renovation of the single-storey duplex included opening the enclosed, dark Victorian plans onto rear courtyards; building a second storey across the back half of both units has captured views and provided extra living space.

The freestanding island bench and wall cupboards in house one are
picked out in rich deep colours in contrast to the white interior.

Architecturally, the buildings are developed as a compact sequence of unfolding scenes where connections between rooms are very carefully controlled. Spaces overlap and fold into one another, allowing social connection. The overlaps are most obvious from the courtyards, with garden beds stretching between properties and numerous gaps in the dividing wall enabling people (and pets) to mingle. From inside, the connections are more subtle, with angles in the building’s façade discretely promoting sight lines between properties, while also sharing the distant harbour views. The upper bedroom levels are almost entirely veiled in adjustable timber screens.

Scenes unfold throughout the two houses in a carefully choreographed sequence.

This project is a bid for a more affordable architecture. Pairing the neighbouring constructions increased the size of the project and therefore enabled building efficiencies, with only one project setup cost. The design ensured that numerous building items are shared, such as a single bank of large photovoltaics and linked access to underground water tanks. Living costs are also reduced through the sharing of household materials and equipment, such as vacuum cleaners, garden equipment and even cars. Space is at a premium in such tiny houses so other everyday items are also shared.

Environmental efficiencies also came into play, helping to maximise light and to make use of recycled materials. Inbuilt planter boxes and large sliding glass doors providing full view to the gardens ensure such small living spaces feel less internally constrained. But it is the social dimension of sustainability that makes these houses so habitable.

Intergenerational living arrangements, such as day care for infants, or elderly care, if ever needed, are a feature of this development, and illustrate how co-housing can address the increasingly prevalent issues of social isolation.

The plywood bookshelf delineates the study upstairs and also offers extra storage or display
space to the lower floor.

On the negative side, the very informal nature of co-housing, based on large amounts of social capital, makes it a difficult concept to institutionalise. Risk management around cost-sharing, and issues such as part-change of ownership, need to be carefully delineated. Householders are tentative about entering such arrangements outside a family-based agreement – and of course disputes can arise even within families.

High-gloss tiles reflect the light making the small bathroom feel larger.

We are all mindful of being too casual in terms of our expectations for socialising between the houses; concerns around intrusiveness are front of mind and there is little spontaneous mingling. But many benefits have arisen that we had not predicted – ranging from simple needs, such as borrowing flour, to sharing household appliances – and there is an ongoing determination to make it work. Other members of the extended family, who are part owners of one of the properties, are kept fully aware of costs involved in any repairs or building improvements.

The sense of security is really tangible, and in our case, the arrangement provides for the different needs across generations.

Profile: Suzanne is Professor of Sustainable Enterprise at UTS Business School and her son Andrew is a director of Benn + Penna Architects, an award-winning professional consultancy in architecture and interior design. In 2014 Benn + Penna were honoured with a NSW Architecture Award for this project – one of the highest accolades possible for architecture in NSW.

Credit: Extracts from S. Benn and C. McGee, How co-housing could make homes cheaper and greener, were first published on www.theconversation.com