Moonah Tree House by Kirby Architects — A Coastal Retreat Rooted in Nature and Craftsmanship

Nestled in the coastal town of Barwon Heads, Australia, the Moonah Tree House by Kirby Architects is a masterclass in integrating architecture with nature. Completed in 2023, this sustainable coastal home draws inspiration from its surrounding landscape and a majestic ancient Moonah tree, a species indigenous to the region and deeply connected to the area’s Traditional Owners.

Architect Kirby Roper crafted the design to preserve and celebrate the tree’s presence. From the kitchen, residents feel as if they are suspended in a modern treehouse, while the expansive decks immerse them in the dappled light and foliage. The tree’s canopy also offers privacy, turning the outdoor spaces into serene sanctuaries.

Design Concept — Nestling into the Land

The brief called for a subtle structure deeply connected to its environment while capturing sweeping views of the ocean and nearby golf course. Instead of elevating the home, Kirby made the counterintuitive decision to embed the house into the landscape. By carefully adjusting the site levels, the architecture achieves a perfect balance — earthing the home while maintaining elevated vantage points through multiple decks aligned with the Moonah tree’s height.

Architectural Form and Materials

The home’s fluid roofline and curvilinear forms echo the undulating contours of the adjacent golf course, from its rolling greens to soft sand bunkers — a fitting tribute for the golf-loving clients.

Constructed from rammed earth, the structure offers natural thermal mass, regulating indoor temperatures throughout the year. Kirby describes this tactile material as “soft and endearing — like a warm hug.” The thick walls lend the home a sense of permanence and security, while also lowering its environmental footprint.

The craftsmanship is equally remarkable. David McDonald Builders executed the details with precision, collaborating closely with the architect to enhance the original design intent and innovate on construction techniques.

Coastal Character and Local References

The Moonah Tree House also channels the laid-back beach town character of Barwon Heads. Inspired by mid-century local houses clad in timber and weatherboards, Kirby reinterpreted the look with vertical blackbutt timber battens. Over time, these will gracefully weather, developing a rich patina unique to the coastal climate.

An external spiral staircase, also clad in battens, connects the three deck levels. It offers partial transparency for views yet maintains privacy — and even protects against stray golf balls. Sculptural yet functional, it anchors the home to the site like a wooden beacon.

Reuse and Personalization

The clients played an active role in shaping the home’s personality. Prior to demolition of the original house, they salvaged cherished 1950s fittings — including colored basins, cedar boards, vintage light fixtures, and taps — which were thoughtfully integrated into the new build. These repurposed elements infuse the contemporary design with nostalgia and layered history.

Despite its striking views and multi-level arrangement, the Moonah Tree House maintains a humble, intimate atmosphere. The combination of tactile natural materials, recycled details, and the way the home gently hugs the land creates a unique coastal dwelling that is both personal and enduring.

Project Details

• Architect: Kirby Architects
• Location: Barwon Heads, Australia
• Year: 2023
• Photography: Jack Lovel
• Builder: David McDonald Builders
• Primary Materials: Rammed earth, blackbutt timber, recycled elements

All photographs are works of Jack Lovel