A Journey of Sustainability and Design: Revisiting a Home in Eltham

Builder: Mulholland Construction

Project Status: Construction Underway

We recently had the pleasure of visiting a project that’s particularly close to our hearts — a house we initially designed around ten years ago, nestled in the hills of Eltham. This project holds not only architectural significance but an inspiring story of sustainability and transformation.

The Project's Origins: A Home on Steep Terrain

The original design was commissioned by a family who sought a home that harmonised with the natural beauty of a steep, green gully in Eltham. The property, which features a dramatic 15-metre fall down the site, posed unique design challenges. It also offered an extraordinary opportunity to create a home that embraced its surroundings — a treehouse-like retreat which is elevated above the valley while being nestled among the bush.

The house was conceived as a dynamic, multi-level experience, each room offering a direct connection to the surrounding nature. The design that was developed incorporated spaces that step up the hill, with multiple levels that respond to the varying terrain. The lower level houses garages and cellars, while the living spaces on the upper levels open up to expansive views of the surrounding bush.

A New Chapter: Embracing Passive House Standards

 Since the original design, the property has changed hands. The new owners, a young couple with two children, are experienced passive house builders. They have undertaken the ambitious task of transforming this project into a Passive House — an energy-efficient standard that goes beyond traditional sustainability measures.

While the main building fabric has been completed, much work remains to be done. Visiting the site was an exciting moment for us, as we had the opportunity to see how the original design was being adapted and refined to meet Passive House requirements. This journey marks a significant shift in the home’s performance, ensuring that it will be comfortable and highly energy efficient all year round.

Passive House Features: A Closer Look

The home’s structure has been designed to maximise thermal performance and reduce energy consumption. A key element of the Passive House approach is the integration of an airtight building envelope . The walls are constructed with 140mm stud framing to accommodate ample insulation, while airtight membranes on both the interior and exterior ensure that the building remains well-sealed.

The concrete slabs offers thermal mass, providing a natural heat sink that helps to stabilise indoor temperatures. Additionally, the slab is disconnected from the cold ground below to minimise heat loss — a technique that is critical for maintaining the home’s energy efficiency. The house is also equipped with a mechanical ventilation system (HRV), ensuring optimal air quality and comfort.

The Cascading Architecture

 One of the most striking features of the house is its cascading stairwell that weaves its way through the site, with rooms at different levels the vallery and bush are captured in a range of ways. The stairs are wide and generous, designed not only for practical circulation but also as a space for moments of connection. Small nooks along the stairwell invite kids to play or sit with friends.

 Each level of the house serves a unique purpose. A cozy sitting room at the lower level overlooks the wetlands below. Above that, a green roof and terrace invite residents to relax in a tranquil space amidst the trees. Further up the stairs, the open-plan kitchen, dining, and living areas provide a sense of flow and connection to the outdoors. The uppermost levels are reserved for bedrooms, bathrooms, laundry and rumpus with the upper level incorporating the main bedroom suite with views of the valley and beyond.

Materials and Integration with the Landscape

Another highlight of this project is the thoughtful integration of materials. The house is clad in beautiful, locally sourced hardwood, a material that, once greyed off, not only matches the eucalypts surrounding the site but also ensures the building blends seamlessly into its environment. With the blue wrap visible, the building currently appears larger than it will once finished. When completed, the home will be also softened by carefully designed landscaping, ensuring it fits well within the natural landscape.

The design is also sensitive to the steep topography, with the house stepping up the hillside rather than sprawling across it. This approach allows the home to sit better within the contours of the land.

What is perhaps most inspiring about this project is the passion and commitment of the new owners. They are not simply building a house — they are bringing an architectural vision to life in a way that aligns with their values of sustainability and craftsmanship. As builders themselves, they are deeply invested in ensuring the home meets the rigorous standards of Passive House design principles which was great to see in practice and learn more about. 

It’s a rare privilege to revisit a project and see it evolve into something even more extraordinary than originally envisioned. We are proud to have played a part in shaping a home that will not only provide a beautiful, functional space for its occupants but will also allow for comfortable, sustainable living.