The projects that took out this year’s Building Designers Association of Victoria’s 10-Star Sustainable Design Challenge are not just ideas on a drawing board, but based on current projects.
Gruen Eco Design’s Hacksaw House, a collaboration with Paperback Design, was the winner of the challenge.
Gruen director Simone Schenkel says the design is based on a renovation and extension of a small brick veneer property in McLeod, Victoria.
The judges described the version submitted for the challenge as “an exceptional and admirable building design with a highly creative and innovative approach”.
Instead of a typical north-south floor plan used for passive solar design, the Hacksaw House has a zig-zagging north-facing facade that brings sunlight deep into the floor plate for long hours during the day.
Reducing the materials footprint has also been a priority, with a strong focus on using recycled materials, including concrete slab, brick and timber, Schenkel says.
“Sustainable design begins at the drawing board and Hacksaw House is an excellent example of how sustainable materials and features can be incorporated into the early stages of building design.”
The project on which it is based is a two-bedroom brick veneer unit, with the same zig-zag shape. The extension is being added as an upper storey, and other elements include vertical greening screens extending from ground level to the upper storey.
The lower brick level has been insulated, and structural insulated panels are being used for the upper level.
“They are made off-site, so there is less waste on-site,” she says.
They are also inherently airtight, and arrive as wall panels that only need the joints sealed to achieve an airtight building shell.
There is also a beauty dividend, as the designer has “complete flexibility in terms of shape”.
The north-facing orientation combined with the south-facing roof does have one challenge – for the best solar generationresults, some north-facing roof is preferred.
Schenkel says this can be solved either by having two different roof shapes on a building, or by locating the solar on a different structure such as a shed or garage that has the optimal orientation for PV.
Her studio has completed a few 10-star homes to date, with all of its projects achieving better than the six star minimum of the building code.
Eight star homes aren’t difficult
Getting a new-build project to eight stars is “not hard”, she says.
Schenkel says the studio’s clients are becoming “much more understanding of operational costs” as having importance.
There are some sustainable design aspects that might need explaining in terms of the benefits, but most now understand sustainability in terms of its relationship to energy costs.
Energy storage and batteries are“more and more” in people’s minds.
“Once you understand the principles it makes so much sense.”
Heat recovery ventilation systems are another technology that makes sense, particularly when the health and wellbeing aspects are taken into account.
Clients are also starting to prefer an all-electric home. Schenkel says around 80 to 90 per cent of clients are going for all-electric.
“A lot of people are stepping away from gas.”
Some still have their hearts set on the gas cooker, she says, but this does not need a mains gas connection, as bottled gas can be used.
Electric induction cooking is one of the innovations that has made all-electric more attractive for some client, she says.
SuHo commended for Sagacious Today
Last year’s Sustainability House [SuHo] was awarded a commendation for its 2018 entry, Sagacious Today, in collaboration with Studio Element Australia.
The judges said the design “carefully considered all aspects of sustainability from passive solar design to thermal performance, embodied energy and life cycle assessment, affordability, regenerative energies and its interaction with the surrounding landscape”.
The design is also coming to life in Adelaide, with the slab for the project poured the same week the award was announced.
Ruth Nordstrom, architecture graduate and proprietor of Studio Element Australia, and ESD consultant with SuHo, says thebuilding will be open to the public and used as an educational resource once it is complete in September 2018.
She says 10star is “not always hard to achieve”. The cost modelling, however, has sometimes been difficult.
For the Sagacious Today project, some of the cost information is being entered into the BIM model during the detailed design phase, rather than being calculated “at the last minute”.
The project will be a demonstration not only of the cost savings achievable in terms of operational energy use, but also of savings in terms of materials and their embodied energy, she says.
The project team will be aiming to source as many of the materials as possible from within South Australia, too.
In terms of thermal performance, the house has been designed to function without a general need for mechanical ventilation for heating or cooling. The design team isalso looking at options including solar PV, energy storage, managing green waste on site and greywater systems.
When complete, it will be used for educating the general public and those in the building industry about sustainability. This will probably include events and client meetings. The studio may also relocate to the space, and some of the consultants it works with may also take up residence there.
While people visiting the home won’t be able to “see what’s inside the walls”, they will be able to physically feel the difference between the temperature of an internal wall and the external temperature, Nordstromsays.
“Without that one-on-one encounter with the building, it is hard for the public to understand what’s going on inside the building.”
For builders and others, having an example of how building sealing improves performance will be a useful tool.
“A lot of people are not aware of how a few small changes with sealing the building can make a huge difference [to energy performance],” Nordstrom says.
There might also be an opportunity to bring groups of students, such as secondary students, through the house where there is an overlap with an aspect of their curriculum.
In its submission on the project, the design team points out that from the onset of designing a 10-star house, “there are challenges in versatility of occupation due to the commonality designers face in the ‘boxiness’ of designing to achieve 10stars”.
“With software having a strong preference for very enclosed rectangular forms it has become a challenge to ensure these houses are designed for living the idealistic Aussie typology that sees families seeking better threshold transitions between their outdoor and indoor spaces, and openness for light penetration.”