The 800kg window is the star attraction at Steve and Kate’s Bondi home

The greatest challenge of a home renovation in Bondi wasn’t the towering breeze block screen but the window that looks into the back garden.

The window weighs over 800 kilograms, and makes up part of a design with a breeze block screen by architects Panov-Scott, who Steve and Kate Hack enlisted to add bedrooms and living spaces to their 100-year-old, semi-detached house.

A home renovation in Bondi included the installation of a window that weighed over 800 kilograms. Sliding door hardware allows the window to open vertically and be concealed within the breeze block screen to become an open space. Credit: Steven Siewert

The window is four metres wide and just over two metres high. Sliding door hardware allows the window to open vertically and be concealed within the breeze block screen to become an open space.

Other components of the window include a pulley system, wire rope and counterweights. The counterweights require precise alignment, just a one kilogram discrepancy causes the window to malfunction.

“The greatest challenge in making this window function as intended was ensuring the precise alignment of all the components,” Sloman Built director Matthew Sloman said.

“This involved co-ordinating everything from the sliding door hardware, sheaves, wire rope and counterweights, and creating space within the walls for the counterweights to move freely.

The original facade was retained. The home is called Bondi Breeze and is a semi-detached house in a row of five.Credit: Steven Siewert

“Site welding and designing the counterweights so they could be adjusted to the right weight was critical—just a one kilogram discrepancy could prevent the window from functioning properly.”

The window weight as a whole was over 800 kilograms and required a crane for its installation.

A breeze block screen with a 800kg-plus window was part of the contemporary design.Credit: Steven Siewert

The window forms part of a towering breeze block screen that creates privacy. A hidden steel frame holds the breeze blocks in place in the design that won a commendation in the alterations and additions for a residential house category at the NSW Architecture Awards.

Breeze blocks emerged in Australia in the 1950s and 1960s, and became synonymous with mid-century modern design. They were unfashionable in the late 20th Century but are in style again and have been popping up in commercial and residential projects in trendy and coastal locations.

The Hacks weren’t initially sold on breeze blocks.

“I was a bit sceptical as to what a two-storey breeze block screen would actually look like,” Steve said. “That was definitely a conversation we had with the architects, it was 100 per cent their idea.”

The breeze blocks have become a talking point for the neighbours.

“All the neighbours want to come in and have a look to see what they can maybe replicate with their house,” Steve said.

“I don’t know to the extent of actually using them, but it might be in the back of someone’s mind.”

Kate said breeze blocks were a foolproof solution to ensure privacy and connection to nature.

“In a high density area like Bondi, the breeze blocks give you privacy but also so much connection to nature. I think that’s quite rare for a suburb like Bondi,” she said.

The semi-detached house is on a narrow lot, approximately 30 metres long and seven metres wide. Reducing the house footprint was part of the brief.

The breeze block screen was complemented in the interiors with polished concrete floors, marble and sleek white lines.Credit: Steven Siewert

Panov-Scott architect Anita Panov said the narrow lot was the best constraint as it allowed them to come up with the design.

“We made the house even narrower than what it was. We don’t think of it as a house that’s been reduced as it’s actually quite generous. There’s a relationship to the garden and the sky,” she said.

Sustainability was a key focus with double-glazed windows, an electric heat pump system and ceiling fans. The sun streams through the window in winter to keep the house warm.

“You sit there on the north side in the sun and there’s no breeze, and it’s beautiful,” co-architect Andrew Scott said.

“What’s really lovely is that it’s always a surprise what the screen actually does. The quality of the light that comes through and the way the shadows bounce. Those things are different all the time.”

The Hacks played with the idea of a renovation in 2019 and the build was completed post-COVID.

Scott said it was too difficult to quantify the exact cost of the breeze block screen, but said it was cost-effective in the context of other similar residential projects in the eastern suburbs.

The breeze block screen was complemented in the interiors with polished concrete floors, marble and sleek white lines.

The home has been nominated in the 2025 Houses Awards and received a commendation at the 2025 NSW Architecture Awards.