Looking at the traditional Victorian facade of Kylie Brammy and George Kyprianou’s home, you would never imagine it hid such a voluptuous and modern derrière.

Physiotherapist Brammy and entrepreneur Kyprianou bought the North Adelaide house in 1999 because they loved its charm and location on the city fringe, close to parkland. Less desirable? Its tiny kitchen, dark living spaces, and badly positioned toilet, just three feet from the dining table. Engaging both an architect and an interior designer to collaborate on a renovation and two-story extension, the couple managed to open up the interior and transform the back of the house into an improbably airy and light-filled retreat.

"The longer you live somewhere, the more you learn about its idiosyncrasies and potential. We lived here for several years before we started our renovation, which helped us understand what we wanted," says Kyprianou. "The rear of the original house was very dark, and functionally, the space just didn’t work. We love having friends and family over for dinner, but the tiny galley kitchen was only just big enough for two people to walk sideways past each other. There was only one bathroom – right next to the dinner table – so it was a bit uncomfortable when guests had to use it! We decided to open the whole rear of the house right up; it’s north facing, which here in Australia gives you beautiful sunshine all day long. We could see the potential in having a big, tall glass structure to let all the light and warmth in."

Around 2005, they approached Phil Harris from Troppo Architects, but the firm was too busy to take on a job with the couple's modest budget. A few years later, the couple happened to stay in a Troppo-designed eco-resort in Broome. It had all the qualities they were looking for: sustainability, space, light, and ventilation. Brammy called Harris again, and this time he agreed to come out and talk.

After bonding straight away, Harris came up with the design that you see today. Says Kyprianou, "The original part of the house is only 20 feet wide, so we extended an additional three feet out to the boundary, which gave us room to put a light-filled guest bathroom and laundry in the middle of the original part of the house. The master bedroom floats on a mezzanine in the void above the living area, with a spacious en suite [bathroom] tucked behind it. To meet the local heritage requirements we had to mirror the roofline of our neighbors on the laneway side of the house, so the extension has a unique asymmetrical shape."

Brammy's physiotherapy practice is located in an old warehouse in the city, designed by Susanna Bilardo from Enoki. By enlisting her help to do the interior design, Bilardo brought softness, comfort, and livability to the house, using lots of natural, warm materials like reclaimed timber and doors. The couple also hung on to some original features of the house, like the historic facade and the original chimney. "Our builder did a great job keeping the existing chimney upright when the walls came down around it," says Kyprianou. "We love its wonky shape."

Since soil space is limited on their lot, Brammy says she grows her veggies “secretly” among the other landscaping plants. "I’ve planted lemons and oranges, espaliered along the fence that extends out behind the barbecue. I love our pool – it provides a “yin” element of cooling, moistening, and grounding to the house, in contrast to the warm and dry materials we’ve used elsewhere. I can actually touch the water from inside through the sash window at the end of the bench seat, which gives me a sense of serenity."

Without much room left for a rainwater tank, which the couple wanted in order to reduce their water consumption (Australia has strict regulations due to drought), they opted to install a clever PVC “water bladder” from Eco Sac. Concealed under the deck, it holds 3,000 liters of water collected from the roof and used to flush the home’s toilets and run the washing machine.

Brammy and Kyprianou wanted the house to be as open and light as possible, but large expanses of regular glass can result in excessive winter heat loss and summer heat gain – and they couldn’t afford two stories of double-glazing. They opted for Viridian ComfortPlus glass, which is coated with an insulated film that is energy-efficient, reduces sound, and filters UV radiation.

The bedroom is up on the mezzanine level, giving the illusion of being in a suspended tree house. However, with the budget running out toward the end of the project, Kyprianou wanted to avoid forking out for a custom-designed walk-in closet in the master bedroom. So he conceived of a simple and cheap storage solution: drilling holes through the wooden roof trusses and feeding inexpensive aluminum closet rods through.

The couple always knew this project would be special. "I sensed the soul of the house the moment I walked through the front door at the first inspection," says Brammy. "It had a story to tell – of happy lives and families – and we are continuing that story."