Christie Walk - an urban ecocity!
Last weekend, I had the opportunity to go on a tour through Christie Walk, an Urban Ecology Australia project designed by Dr Paul Downton to create an inner city community with integrated ecology, low environmental impact, and enhanced human wellbeing. This place was amazing! It felt like walking through a park despite being in the middle of Adelaide’s CBD with a technically high-density housing situation. The 10-building, 27-dwelling space was all built by the residents, from building, to paving, to planting. And how the space has matured!
Keep reading below to learn about community shared facilities and projects, garden spaces including a rooftop garden, eco home design, and building materials!
The first aspect we looked at was the community area - with a shared laundry, library and community kitchen/living space. The laundry is actually fantastic: it costs $1.60 per load, covering washing powder, running costs, machine repair, and eventual replacements. By having the washing machines community owned, the overall cost is reduced by sharing the costs, enabling better quality machines and repairs being less of a hit to the budget. There are 1 or 2 dryers, but, as in the photo below, line drying is highly recommended. I think the washing lines hanging out from the balcony is a fantastic idea - they don’t take up space or look ugly within the balcony, and they’ll get extra air flow and sunlight to dry faster!
As we walked along, we stopped in a round courtyard area to have a look at the apartment staircase. The design is purposefully open, to allow hot summer air to flow upward through the staircase and past the plants, cooling down as it moves. The stairs are sheltered, and the climate remains relatively stable year-round for the comfort of the residents. There was also a beautiful mosaic on the side of the stairs which I thought was a nice touch - I find it interesting, the intersect of art with these community projects. It brings a sense of home and beauty. And, did you notice the greenery at the top of this building??
There is a rooftop garden! It is a great way to insulate the building, cool down the city, provide a community meeting space, and provide habitat for insects and birds. There is a special layering process (see 2:10 on this video tour of the roof garden) that prevents water seeping through, resulting in just 35cm of topsoil supporting an impressive biodiversity of plants - native on one side, and edible fruit and vegetables on the other. The largest plants include a Melaleuca lanceolata (Tea Tree), lemon, and guava. There are even two bee hives, which are hired at $100 each per year plus about 4kg of honey at the end of the year! These are maintained by the hive owners, the cost (and the honey!) is shared between all residents, and the bees increase pollination in the whole area.
The rooftop also has a small shed, covered with solar panels. The solar panels here, with gas assisting, pump stormwater up to the rooftop garden and pump hot water throughout the buildings. Pretty nifty use of space! An interesting note, though, is the difference of the solar panel efficiency between buildings due to the time difference. As the project began in 1999, a large number of the early solar panels produce the same amount of energy as just a few that were upgraded on the apartment building in 2019. So, environmentally-friendly is a constantly changing standard as technologies improve. Additionally, there is the quandary of solar panel disposal, as at the time of writing, there is no safe way of recycling them. The end of life for most solar panels is not near though - do not despair! Humans are expert problem solvers, and it is doubtless a solution will be reached within a decade.
The next aspect we looked at was house design. An interesting aspect was the use of bay windows: I thought they were just for looks, but they increase the area available for winter sun to reach indoors and heat up the thermal mass floors (polished concrete - really beautiful and heat absorbant!). There are also lots of louvers (in the lower levels of the bay window below, and featured in all the buildings) which allow temperature control by the residents. Until the population aged, there was no need for an air conditioner or heater, and the few that were retrofitted are rarely run due to the excellent insulation and easy temperature regulation. Deciduous vines are present on most buildings to allow winter sun in, and block summer sun, cool down the building, and increase privacy. Also, they are pretty beautiful! The one below is a grapevine and I think I spotted a Wisteria on the staircase, which will be simply gorgeous in the spring.
Building materials are varied between the buildings. They include straw bale, Hebel blocks and rammed earth. Straw bale is an excellent building material (featured in the picture above) and can be constructed with little specialised equipment, just requiring expertise in advising (check out the “couch tour videos” of a two- and three-storey strawbale home). It has excellent insulation properties, creating a comfortable internal environment year-round. It is renewable and durable, with a straw bale house able to last at least 100 years in an inclement position in England. Hebel blocks are used in the townhouses below. They are autoclaved aerated concrete (AAC): a kind of lightweight, aerated, concrete combination brick - they use less concrete than solid concrete, reducing their impact, are lightweight and therefore don’t require specialised equipment to carry it up multiple stories, and are highly insulating and soundproofing.
Finally, a massive vegetable garden is below. The community hold monthly working bees to maintain the gardens, though everyone has the option to chip in differently and some may want to be more or less involved in the garden. This vege garden looked great! The city provides a warmer environment, and it is protected by the buildings on either side, so a variety of crops can be grown to great potential. There are also fruit trees (deciduous, so they provide shade, cooling, and privacy too) and the grape vines on buildings. Elsewhere there are a combination of native, flowering, and edible plants, which are great for biodiversity and providing a sense of nature for the residents. The gardens are a fantastic way to be productive, cool the area, increase biodiversity, and provide a sense of community, really bringing together the aims of Urban Ecology Australia’s fantastic city project.
I hope you enjoyed my mini summary and have lots of ideas for urban eco house design! I myself would love to be involved in a project such as this. With just three similar projects in Adelaide and surrounds, there is plenty of space to multiply these projects and follow Christie Walk’s example.
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