Old meets new in Williamstown: A Modern Heritage extension done right

When asked about the challenges his Modern Heritage extension faced from the outset, homeowner Stuart Hillen pinpoints the major one clearly.

“There’s a heritage overlay on our street, and this meant the facade and the original cottage had to stay the same from an external perspective.”

This reality became the starting point for Hillen’s high-end renovation and extension on his family’s dream property in Melbourne’s much-sought-after beachside suburb of Williamstown.

Designed by Kate Vernon Architects and built by Ultra Builders, it’s a project that celebrates the charm of a double-fronted Victorian while adding a contemporary rear addition wrapped in Hardie™ Oblique™ Cladding (300mm, installed vertically).

Letting ‘heritage’ have its moment

For Vernon, the design intent was always about balance; she set out to retain what made the original home so special while making it function beautifully for a growing family.

“The design intent was to create a lovely family home,” she says. “We wanted to make the most out of the original charm that the heritage house brought to the project, while adding new spaces for the young family to enjoy and grow into.”

The team approached that ‘old-meets-new’ transition with care, she adds: “We created a ‘link’ between the old house and new build, which allows the original house to really have its moment before [the renovation] transitions through to the new.”

This also helped Vernon to manage the realities of heritage planning.

“Every council is different in terms of what they will accept in a heritage overlay, and [Hobsons Bay City] Council is quite conservative,” Vernon says. “We had to keep the overall envelope and visibility of the new addition from the street to a minimum.”

A bold new rear form with modern lines

Once the rear addition was possible, Vernon still wanted the extension to feel overtly contemporary, without copying the original weatherboards or overpowering the front rooms.

“We didn’t want to clad the new addition in weatherboards, or have it look too similar to the old part of the house,” she says, explaining that this is where Hardie™ Oblique™ Cladding became the hero material for the extension. “The cladding was a great choice to achieve a painted timber-look cladding that we could use vertically for a subtle point of difference.”

The 300mm vertical boards did more than deliver a modern facade; they also created a clever visual relationship with the home’s heritage skin.

“The rhythm of the 300mm wide vertical boards achieves a similar pattern of the 150mm wide horizontal weatherboards on the original house, but again it provides a subtle difference between the old and new,” Vernon says.

In classic Modern Heritage style, she says the junction between eras was designed to feel intentional rather than accidental: “The ‘link’ between the original house and the new addition creates a lovely intentional threshold between the old and new.”

Built for renovation realities

From the builder’s perspective, Modern Heritage renovations demand equal parts experience and humility, because “you never fully know what’s behind the walls until you open them up”.

“The biggest complexities are the unknowns,” says Ultra Builders Managing Director Damien Rinaldi. “You’re working with construction methods and materials that are sometimes more than 100 years old, and you can’t be certain what you’ll find until you open things up.”

Even with solid planning, surprises can still crop up, he says: “The original bluestone pitcher footing system did lead to increased labour costs associated with their removal and the necessary additional subfloor works.”

On a project like this, where the extension is wrapped in vertical 300mm boards, getting the cladding straight and installed correctly were critical.

“The most important factor was a plumb frame,” he says. “Following that, we had to make sure all battens were installed well, level and spaced correctly.”

His team used the Hardie™ Structural Batten to support a speedy installation and long-lasting performance, with Rinaldi saying the product was “easy to install and work with, enabling reduced labour time”.

Rinaldi also touched on the role of ventilation and drainage in modern facade systems: “The castellations and slope on the battens ensure airflow and prevent any water pooling, making the product durable and compliant with NCC [National Construction Code].”

Tips for your own Modern Heritage transformation

If you’re planning a similar renovation, especially within a heritage overlay, Vernon’s advice is to understand the constraints early on, then design with clarity and confidence.

“It’s important to have a good understanding of the site and any specific or local planning and heritage constraints so you know what you’re able to do,” she says.

From there, it’s all about creating a genuine flow between old and new: “Respect and highlight the original part of the house that’s being kept and add to it in a simple but also modern way to distinguish between the old and new.”

Rinaldi says that experience and precision are what will pay off most: “Being able to anticipate what you will encounter and how best to facilitate a seamless finished product is paramount.”