Macleay Island Retreat
Tess McVicker’s house was designed on Mackley Island in Morton Bay, an hour’s travel from the Brisbane CBD. It was designed to be built with UMBS (Universal Modular Building System) – a lego-like proprietary building system designed for maximum energy efficiency and design flexibility.
The windows towards the bay are un-shaded as they face south-east away from the sun in Australia. North-west facing glass sliding doors on the upper floors are both shaded.
The brief called for a two bedroom structure (one being a guest-room), with an open plan and with regard to views toward the bay and islands, as well as for a spacious media and graphics home office for a single person.
The site slopes initially moderately, then steeply down to the bay. There is magnificent tree-growth on the block and water views to the south and east to Stradbroke Island, Russell Island and Lamb Island.
By cutting a shelf into the land from where the land starts to slope steeply down, a level carport was to be provided, wedged between a glassed home office unit which is “suspended” above the steeper ground on posts, and alongside it uphill, by a retention-walled rainwater storage tank for 40 000 litres of water (enough for 9 months use for one person). With the median rainfall on the Morton Bay Islands being between 1600 and 2400 mm/year, the annual yield from a 45 m² roof will be in the order of 72 to 90 000 litres.
The main structure was to be built on top of both the home office and the rain water tank spanning the carport.
“Smart-flow” gutters would have diverted most of the leaf litter over the edges, and a 100 litre in ground first-flow diverter would have directed dirt and bird deposits from the 45m² roof to the in-ground trickle irrigation system. When the first flow diverter fills, water starts to enter the rainwater tank through a membrane filter. A specially designed laser-light monitoring device trips a solenoid valve open and shut to allow 60 litres @ a time of back up town water to enter the tank when the water level in the tank hits a “preset” – lowest allowed level. A pump maintains adequate water pressure from the tank to the house.
The tank water was to be used directly for:
a: Solar hot water heater
d: Hand basins
e: Kitchen sink
and via carbon filtration and UV-sterilisation for drinking water to meet and supersede council requirements with regard to health risks from tank-water.
A biological effluent treatment system to be buried into the hillside, the main tank forming the curve of the retention wall where the driveway turns into the carport. Treated water to be distributed in ground throughout the upper slope as demanded by the local council.