By Simon Johanson
TWO eco-friendly houses are rising from the ground in suburban Melbourne built from a plant normally associated with 1960s hippie heaven: hemp.
In an Australian-mainland first, the walls of the semi-detached homes in trendy inner-city Northcote will be made from the cannabis-based building product Hempcrete, pioneered by a Queensland company for its carbon-neutral properties.
The eight-star green rated homes are the inspiration of two medical practitioners, a father and daughter team who will live side by side with their three generations in the one construction.
Along with the hemp walls, the architect-designed homes will have a solid rammed-earth dividing wall, double-glazed windows, underground water tanks and grey-water recycling, as well as solar panels for electricity, hot water and hydronic heating.
Michelle Leadston and her father, Bill, bought the large block in Northcote three years ago intent on building two sustainable homes for their families to live in.
''I've always said I'm going to look after my parents when they get old,'' she said. ''This was the most convenient option. The babysitter's next door. And it's not too close. There's a big wall in between.''
Both families wanted to share a common backyard and other design features such as lower, child-friendly windows and intimate, internal courtyards, said Dorit Przyborowski of Steffen Welsch Architects.
The internal walls will be lined with magnesium oxide boards instead of plaster.
The generational differences were also evident in the design. Michelle put more emphasis on child-friendly spaces, Bill on the living and dining areas, Ms Przyborowski said.
If land was subdivided in future, both houses can be independent, she said.
Hemp from local farms will be delivered to the building site in shredded form, mixed with lime and compacted in formwork to make the exterior walls, using techniques similar to rammed earth construction.
''This is one of the first in Australia,'' the home's builder, Stuart Dunne, said.
''People have done bits and pieces but this is probably one of the largest projects to date.''
A drawback of using hemp was that it was labour intensive and therefore costly, he said.
Sustainable architecture is not new to Bill Leadston.
He built his present home in North Balwyn 30 years ago with north-facing orientation, slab heating and solar hot water.
Despite its obvious green benefits, Darebin Council opposed the new building's design forcing an appeal to the Victorian Civil and Administrative Tribunal, Dr Leadston said.
''They virtually said, 'If you want it, you've got to go to VCAT','' he said.
Construction of both homes will cost $1.6 million and is expected to finish in November.
The Age would like to hear about new, innovative buildings, materials, methods, designs or services.
sjohanson@theage.com.au