Australian architecture firm SJB’s distinctly sophisticated aesthetic is deliciously high-end, without being ostentatious. In recently restoring an interwar building in Sydney’s inner-city suburb of Redfern, they applied their signature style to great effect, while still maintaining the structure’s original character.

When the practice’s director of architecture, Sydney, Adam Haddow purchased the building’s new penthouse apartment, he knew it was an investment that had design integrity and any alterations that needed to be made would be minor.

His ensuing scheme didn’t start to come together until halfway through the design process. “My partner and I realised what we actually wanted was a garden and this made us change the way we looked at the apartment,” Haddow says.

Incorporating a generous amount of green space into the plan would be a challenge, but it certainly wasn’t impossible. So he turned the roof into a garden and made sure the existing outdoor area was suitably leafy. An outdoor bath was also installed on the apartment’s southern side, just outside the kitchen, and an outdoor fireplace on the north, where the view is unobstructed.

The gardens work as hard as the internal spaces in providing a sense of comfort and private retreat and in this respect the project is just as much about landscaping as it is interior design.

However, it’s the interior’s stylish combination of fine detailing, robust materiality and sensual finishes that lends the apartment its most compelling design expression and for Haddow, designing his own home was a rare opportunity for experimentation. “Almost every detail was about me trying something out so that I can use it on another project,” he explains.

As a result, steel French doors open into the depth of the walls to maximise space, and marble flooring is used at the threshold between rooms. This exquisite detail enriches the predominantly off-form concrete material palette, while contrasting with the living areas’ European oak floorboards. Visually, it serves to compartmentalise the apartment, offering a sense of intimacy even though the kitchen, dining and lounge are open plan.

Blurring the boundary between inside and outside is a theme clearly articulated throughout the interior, from the living areas’ stone feature that extends outdoors to a series of skylights in the entry, bathrooms and internal corridor. Haddow’s overall scheme embraces the idea of letting the outside in and celebrates the experience of ‘living in the sky’.

Even his use of blue carpet in the bedrooms is a nod to the heavens above. It’s an unexpected colour choice and one that reveals his fearless appreciation of bold finishes, especially in the kitchen, which boasts bright-green joinery. “I do love green; it’s a beautiful colour,” he says. “But I also wanted to make the kitchen work with the garden.”

In furnishing the apartment, Haddow selected new pieces, such as the Chipperfield dining table, to complement items he and his partner already owned, including B&B Italia’s iconic ‘Big Mama’ armchair and ottoman. The styling is crisp, modern and relaxed and while it’s definitely high-end, there’s nothing pretentious about the overall aesthetic. This is, after all, very much a home to be lived in and enjoyed.