Water self-sufficiency for an urban home: Gladesville House by your abode
Westminster Road, Gladesville NSW
The design process is very rarely described as easy. More often than not a realised project, be it an extension for a small family or a new billion dollar public facility, is the sum of meeting a myriad of requirements – from the challenges a particular site proposes, to the specific needs of a client.
The Gladesville House is one instance where these requirements have led to solutions that add more value to the finished product. Designed by your abode, the brief asked for an existing house to be redesigned and made more appropriate for their life. It needed to be cooler in the summer and warmer in the winter, with the clients seeking to include as many environmental initiatives as possible within their budget.
The new timber-framed home is designed to achieve optimum northern orientation, and features a highly insulated building envelope, which means that there is very little need for supplementary heating. At the same time a 3kW photovoltaic system is a substantial source of energy.
Of importance for both the clients and the design team was maximising water efficiency, with your abode’s design and construction director Darryn Parkinson noting that the home’s self-sufficiency for water is particularly innovative seeing that it is located in an urban environment.
“It was not that long ago that the majority of the country was gripped by a major drought with substantial water restrictions,” he explains. “Water is a very scarce resource in Australia so we believe it is incumbent on all designers and builders to maximise the water efficiency, recycling and re-use in all dwellings.”
Self-sufficiency was achieved through the entire roofing area, made of Lysaght Custom orb roof sheeting and Lysaght half round gutter, being connected to four rainwater tanks that can hold up to 24,000 litres of rainwater storage.
“We find the biggest impediment to large rainwater storage strategies is often the space in order to locate the storage tanks in an economical manner,” says Parkinson.
“In this particular case, 4 x 6,000 litre above ground rainwater tanks have been located along the Southern boundary of the house. In doing this, we have utilised what is normally an unused, wasted area of land and put it to a very productive use.”
When it rains, all roof water is collected via charged downpipes and sent to the rainwater tanks. A first flush diverter collects and diverts the majority of the first flush of roof contamination away from the tanks, which keeps the water entering the tanks as clean as possible.
The water in the tanks is then pumped into the house via a Davey pump with a Davey RainBank system, which automatically selects the water source for toilet and laundry applications. Rainwater is given priority over the mains water supply, which is only used when the tank is empty or in the event of a power outage.
To ensure the water is clean and bacteria free, the pumped water flows through a micron pleated filter, a Silver Carbon filter, as well as a UV filter.
Parkinson notes that the effectiveness of this system is based on the premise of regular rainfall, but adds that since completion the house utilises recycled rainwater 80 to 90 per cent of the time.
Additional strategies to maximise the water efficiency of the building is the incorporation of water fixtures that have low or very low water usage. This includes the Astra Walker Icon Tapware and the Villeroy and Boch Omnia Pro toilet suites. The home’s hot water needs are supplied by a gas boosted evacuated tube solar hot water heating system from Apricus.
Complementing this hot water system is the use of EcoVerta water diversion devices, which were installed in the bathrooms to recycle the dead water from the hot water pipework back to the rainwater storage tanks.
Supplied by Melbourne-based firm, Advanced Eco Technologies, EcoVerta automatically recovers the cold water normally lost down the drain while users wait for the hot water to reach the faucet, which can typically take between a few seconds to a few minutes depending on the distance between the bathroom and the hot water heater.
The EcoVerta devices do not require any additional power, pump or batteries to work, instead running on water pressure in lines. All models in the range are compatible with mains pressure water heating systems, including solar, heat pump, gas and electric storage types.
According to Parkinson, all products and materials were chosen for their quality and sustainability credentials, but he encourages architects and building designers to do their own research before specification.
“Satisfy yourself regarding the environmental claims of products and material suppliers, they are not always what they claim to be,” he advises.
Parkinson is also confident that it is possible for all urban homes to be at least more self-sufficient for water than is currently the norm.
“There is a growing impetus for more people to become more self-sufficient for their energy needs, and I feel that the same will eventually apply to water,” he says.
“In my experience, there are two common challenges faced by architects and designers in trying to maximise water efficiency in homes: client resistance to using and drinking rainwater, and the perception that in an urban environment you are not actually allowed to use rainwater within your house.”
But as the Gladesville House testifies, when the right set of requirements align, a project can fulfil more than what popular opinion expects of it, including becoming almost entirely self-sufficient in its water needs despite being in an urban location.
Photography by Thomas Kayser