Sanctuary Magazine Issue 5 - Thornbury, Melbourne Sustainable House Profile

Renovator’s delight

A Melbourne Californian Bungalow is given a contemporary sustainable makeover

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bed 2

winter deck

study / retreat

pantry bed 1

bathroom laundry

kitchen

living

balcony

study

guest / bed 3 dining

Ground level

summer deck

Upper level

The rammed earth walls not only provide thermal mass in the home but are a strong aesthetic feature of the house’s interior.

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hen Nash and Meaghan Popp bought a Californian Bungalow in the inner Melbourne suburb of Thornbury in 2001, it was a typical renovator’s delight. “It was so dark in here, you had to turn the lights on even in the middle of the day,” Meaghan remembers. “There were holes in the floor and flaking plaster and lathe on the walls.” In 2004, the Popps wanted to build an environmentally sustainable extension to increase the building’s light and reduce its operational energy use. They encountered more difficulties than they had anticipated. “You must remember that four years ago, to build sustainably was still a bit freaky,” recalls

Steffen Welsch, a local architect who the Popps contacted after they had seen his advert in the local newspaper. “There has been a significant shift in the past four years, but at the time we faced many hurdles and expenses due to the lack of experience and resistance to new ideas among builders, suppliers, installers and so forth.” Steffen’s launching pad for planning the extension was to maximise light by capturing as much available sunlight as possible. The challenge was that the backyard faced south (in other words, received little direct sunlight) yet this was where the extension had to go. To overcome this, Steffen built an external courtyard between the existing house

and the new extension. Thanks to its northern orientation, the courtyard receives sunlight all day, which in turn enters the living area (in the extension) through double-glazed windows. The kitchen, which links the old house to the extension, has a lower ceiling than the adjoining dining room. A row of north-facing windows fills the wall space between the two ceilings and these admit light into the dining room even during the winter months when the sun is lower in the sky. In addition to a horizontal extension, the Popps built a second storey. This created fresh opportunities to reduce the building’s operational energy use. Windows were put in at strategic

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... a good-looking building that doesn’t necessarily identify itself as a sustainable building, because it doesn’t look low or hi-tech; it just looks good

The stairwell acts as a heat shaft as the warm air from downstairs is drawn up and can escape through the open upstairs windows.

locations in the stairwell and upstairs to facilitate passive cooling: when nighttime creates cooler air currents, the stairwell acts as a heat shaft by drawing warm air from downstairs to upstairs, where the warm air can escape through the open windows. As a consequence of building a second storey, the Popps made an aesthetic decision to install slanted loft-style ceilings in the upstairs rooms. These turned out to have a practical benefit because the north-facing roof is the perfect spot to mount solar photovoltaic panels. Consequently, the roof was built at a pitch to maximise solar access for the panels. Nash says that merely having the

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one-kilowatt solar system has helped to make the family more conscious of, and conservative in, their energy consumption. “Even our two year old son, Xavier, turns the lights off when he leaves the room!” Steffen observes that the house is “a good-looking building that doesn’t necessarily identify itself as a sustainable building, because it doesn’t look low or hi-tech; it just looks good.” Perhaps no feature of the house illustrates this more vividly than the facade of the upstairs extension. Slender, elegant timber battens run horizontally along the exterior of the north-facing walls, which face the street. The distance between each slat has been specifically

gauged in order to let winter sun through (to warm the walls) and to keep summer sun out (to keep the walls cool). The effect is visually arresting and, simple as it is, puts a contemporary spin on this Californian Bungalow while simultaneously helping to regulate the internal temperature upstairs. Rammed earth was used for the extension’s central wall as well as the east-and west-facing external walls. Rammed earth has a high thermal mass, meaning it holds heat well, only releasing it when the surrounding temperature drops. The walls have been insulated on the outside to improve their insulation value and aside from its excellent thermal mass, the rammed earth is a strong

The elegant timber battons are designed to let the sun through to warm the walls in winter and keep the walls cool in summer.

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Whenever we’ve been away, it’s always really nice to come back here. Even when it’s pouring rain, you see it bouncing off the deck, but inside here, we’re cosy

Materials were sourced locally for the house including the concrete benches in the kitchen and bathrooms made by a local artisan.

aesthetic feature of the house’s interior. The walls are a sandy colour, with traces of mica that glint in the sunlight. There’s a textural quality to the surface and it’s easy to see why Meaghan doesn’t want to hang paintings on these walls. Materials were sourced locally where possible in order to reduce the level of embodied energy in the house’s construction and lifecycle. To that end, the Popps contracted a local artisan to make the concrete benches in the kitchen and bathrooms. The timber flooring, outside decking and the stairs are made from sugar gum, a plantation-grown native hardwood harvested in South Australia. The rammed earth for the walls was sourced from

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Kyneton in regional Victoria. The external timber battens are made from western red cedar that is sustainably grown and harvested. The ambient temperature of the central living area is generally comfortable through the year. In winter, the east-and north-facing windows maximise the sun’s light. The rammed earth walls capture the heat from the sun and slowly releases it during the night. On cold mornings the Popps use a hydronic heating system to prewarm the house before daylight. The gas water heater that supplies the hydronic system is integrated with a heat pump. The heat pump absorbs heat from the surrounding

air (like a fridge working in reverse) and expels cold air back into the atmosphere until the water in the storage tank reaches the optimum temperature. The experience of renovating their house to make it more environmentally sustainable was often challenging. “Builders today are starting to realise they need to think outside the square and work with different materials but at the time we were renovating, they were resistant to new ideas,” says Meaghan. Yet for the Popps it has been a rewarding experience. “It’s a great place to be in. Whenever we’ve been away, it’s always really nice to come back here. Even when it’s pouring rain, you see it bouncing off the deck, but inside here, we’re cosy.”

The living room area is kept warm in winter thanks to high levels of insulation, doubleglazed windows and the concrete benches and rammed earth walls that absorb the sun’s heat and slowly releases it back into the room.

Designer: Steffen Welsch Architects www.steffenwelsch.com.au Location: Thornbury, VIC Photographer: Rhiannon Slatter Features: n 1kW Origin Energy grid-connected photovoltaic power system n Greenheat integrated hot water and hydronic heating system n 340 litres Quantum Energy hot water heat pump and Rinnai instantaneous gas hot water n Hydrotherm hydronic heating panels n Auspoly batt wall and ceiling insulation n Recycled Styrofoam from old industrial fridges ceiling insulation n Concertina foil batts floor insulation n Protherm Reflecta Guard and foil-backed blanket roof insulation n Moen double-glazed windows n Optimal cross-ventilation n External courtyard maximising sunlight

n Fixed

and retractable external sunshades Verosol internal window blinds n Rammed earth walls n S  ustainably managed plantation Sugar Gum flooring, stairs & decking, and Western Red Cedar battens n Asko four-star water rating dishwasher n  Megaman compact fluorescent and LED downlights n SilverScreen

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