Geelong West
Project Overview
Matt and Sharon’s Californian bungalow in Geelong West was uncomfortable through the seasons and its layout no longer suited how they wanted to live. Rather than move, they chose to renovate and extend: keeping the heritage character they loved while transforming the home’s performance, accessibility and connection to the outdoors.
The project involved a full renovation of the existing bungalow and a contemporary rear extension, together with a complete building fabric upgrade designed to achieve EnerPHit-level Passive House performance. The entire project was modelled in PHPP (Passive House Planning Package) to test and optimise the energy performance outcomes before construction began. Every floor, wall and ceiling was insulated, airtightness membranes were installed throughout, all windows were upgraded to double-glazed units, and the new extension was built with heavier 140mm wall frames and deep roof and floor construction to achieve passive-equivalent performance.
An 8 kW rooftop solar PV system and rainwater harvesting were added to reduce running costs and environmental impact. The completed home achieves a 6.5-star energy rating across the whole house, which is better than the majority of new builds in Victoria, and demonstrates what is possible when Passive House thinking is applied to a heritage renovation.
This project is an important example of how to bring an older home up to the highest performance standards through a complete fabric overhaul, and it is one of the most common enquiries we receive from clients wanting to know how to renovate their existing home rather than start from scratch.
The project involved a full renovation of the existing bungalow and a contemporary rear extension, together with a whole-house energy performance upgrade. Every floor, wall and ceiling was insulated. Airtightness membranes were installed throughout. All windows were upgraded to thermally improved double glazing. An 8 kW rooftop solar PV system and rainwater harvesting were added to reduce running costs and environmental impact.
The completed home achieves a 6.5-star energy rating, which is better than the majority of new builds in Victoria. It demonstrates that heritage homes do not have to remain energy-poor; with the right design approach, an older house can be transformed into a comfortable, efficient and durable family home without sacrificing its original character.
The interiors were designed collaboratively between Sharon Dyke and Sunpath Architects, with construction by Matt Coster of MC Built.
Project Details
- Location: Geelong West, Victoria
- Project Type: Heritage Renovation and Extension
- Energy Rating: 6.5 Stars (whole-house upgrade)
- Certification: Targeting Passive House Enerphit
- Construction: Full renovation with contemporary extension
- Energy: 8 kW rooftop solar PV, all-electric
- Water: Rainwater harvesting
- Windows: Upgraded double-glazed throughout
- Insulation: All floors, walls and ceilings insulated with airtightness membranes
- Completed: 2024
- Builder: Matt Coster, MC Built
- Interior Design: Sharon Dyke and Sunpath Architects
- Architect: Niall O Healaithe, Sunpath Architects
Completed Project
A Black Box and a Bungalow
From the street, the home reads as a well-maintained Californian bungalow. The heritage facade, proportions and streetscape contribution are preserved, and the original character of the front rooms has been retained and enhanced through careful restoration.
The rear of the home tells a different story. Matt was inspired by the Japanese shou sugi ban tradition of charred timber cladding, and the extension takes the form of a simple black cubic volume that contrasts deliberately with the warmth and texture of the original bungalow. This black box is then manipulated: the living room wall pushes outward to capture better views, light and connection to the garden, while simultaneously creating a sheltered alfresco deck beneath a shading pergola structure for outdoor dining. On the opposite side, the bedroom wall projects out to form vertical slot windows that draw morning and evening light along the side courtyard passageway without being overlooked by neighbours.
Matt also wanted to incorporate board-marked cast concrete textures in the alfresco barbecue area, planter beds and seating, contrasting these with natural hardwood timbers. The result is an outdoor living space that feels robust, crafted and distinctly different from the lightweight timber decking that dominates most Melbourne renovations.
Interior Character
The interiors are clean, warm and contemporary, with colour cues that echo the contrast between the dark exterior and the lighter heritage front. Sharon is creative and passionate about arts and graphics, so the design provides generous wall space throughout for displaying their collection. We also wanted to feature textures and treasures from their New Zealand heritage: Sharon’s and Matt’s mothers both create handworks including knitted creatures like the taniwha, tapestries and blankets, and we designed specific places throughout the home to display and celebrate these family pieces.
Every space is designed to be stylish and cosy while being practical, robust and low maintenance. The connection between indoors and outdoors was a priority throughout; Matt and Sharon love outdoor living and the design maximises sheltered garden spaces, covered entertaining areas and visual connections to planting from every main room.
Construction Process
Complete Fabric Overhaul
This project demonstrates how to achieve Passive House-equivalent performance through a complete upgrade of an existing building’s thermal fabric. Rather than simply extending the house and leaving the original bungalow untouched and uncomfortable, we treated the entire home as a single thermal envelope and upgraded every element.
Every floor, wall and ceiling in the existing bungalow was insulated, including areas that are typically overlooked in conventional renovations such as subfloor spaces and internal walls between heated and unheated zones. Airtightness membranes were installed throughout to reduce uncontrolled air leakage, draughts and moisture migration.
All existing windows were upgraded to double-glazed units with improved thermal performance, replacing the original single-glazed timber windows.
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The Extension
The new extension was constructed with heavier 140mm wall frames and deep roof and floor build-ups specifically designed to achieve passive-equivalent performance. This additional depth allows significantly more insulation than standard construction, bringing the new portion of the home close to Passive House new-build thresholds.
The entire project was modelled in PHPP to verify the energy performance and test design decisions before construction. This is the same energy modelling software used for all our certified Passive House projects, applied here to a renovation context to ensure the investment in fabric upgrades would deliver measurable results.
The shou sugi ban-inspired black cladding on the extension is both an aesthetic choice and a practical one: the dark metal cladding is durable, low-maintenance and provides a bold contemporary contrast to the heritage bungalow without competing with its traditional character.
Concepts and Design Process
Two Buildings in Dialogue
The design concept treats the project as a conversation between two distinct architectural characters: the existing heritage bungalow with its traditional proportions, timber detailing and warm palette, and a new black cubic extension that is unapologetically contemporary.
The Japanese shou sugi ban tradition gave us the language for the extension: a simple, dark, precise form that sits behind the bungalow and reads as a separate volume rather than a conventional addition. From there, the design developed through a series of push-and-pull moves. The living room projects outward to capture garden views, light and a stronger connection to the landscape. This same move creates a sheltered pocket on the opposite side: a covered alfresco dining area beneath a timber pergola that provides shade and weather protection for year-round outdoor use.
The bedroom wall projects in the other direction, creating vertical slot windows along the side passage that bring controlled morning and evening light into the room without compromising privacy from the neighbouring property.
Designing for Heritage and Character
The heritage front rooms retain their original proportions, ceiling heights and detailing. The transition between old and new is handled through a linking zone that allows each part of the home to maintain its own identity while functioning as a coherent whole.
Sharon and Matt’s New Zealand heritage was an important design influence. We discussed how to create a home that could display family handworks and art alongside contemporary finishes: places for the taniwha, for tapestries and blankets made by their mothers, for Sharon’s growing art collection. The interior design balances gallery-quality wall space with warmth and domestic comfort, so the home feels personal and curated rather than clinical.
The outdoor spaces were designed with equal care. Matt’s vision for the board-marked concrete barbecue area, planter beds and built-in seating gives the garden a permanent, crafted quality that integrates with the architecture rather than being an afterthought. Hardwood timber elements contrast with the concrete textures, and the pergola structure provides the dappled shade and overhead enclosure that make outdoor dining comfortable through Melbourne’s long summers.
Sustainability and Energy Performance
This project targets EnerPHit-level Passive House performance, the Passive House Institute’s standard for the retrofit and renovation of existing buildings. The entire project was modelled in PHPP to test and optimise energy performance before construction began.
The energy upgrade measures include:
Comprehensive insulation to all floors, walls and ceilings in both the existing house and the new extension, creating a continuous thermal envelope across the entire building. The new extension uses heavier 140mm wall frames with deep roof and floor construction to achieve insulation levels approaching those of a new-build Passive House.
Airtightness membranes installed throughout to reduce uncontrolled air leakage and draughts. The same attention to sealing junctions, penetrations and transitions between old and new construction that we apply to our certified Passive House projects was maintained here.
Upgraded double-glazed windows throughout the existing house, replacing the original single-glazed timber windows. The new extension uses high-performance double-glazed units with thermally improved frames.
An 8 kW rooftop solar PV system generating a substantial proportion of the home’s annual electricity consumption. The all-electric design, with no gas connection, means the solar system offsets the full range of household energy use.
Rainwater harvesting for garden irrigation and non-potable household use.
Low-VOC materials and finishes selected for indoor air quality, durability and environmental responsibility.
The completed home achieves a 6.5-star energy rating across the whole house, including the existing heritage bungalow. This is a significant result for a renovation and exceeds the performance of most new-build homes in Victoria.
This project is particularly relevant for clients who love their existing home but want it to perform better. A complete fabric overhaul, guided by PHPP modelling, can transform even a century-old bungalow into a comfortable, efficient and durable home. We regularly receive enquiries from clients wanting to understand how to achieve this for their own heritage or older home, and this project demonstrates the approach and the results.
Read our full guide to Passive House / Passivhaus here.Â
“Niall’s design was perfect for our Californian bungalow, retaining the charm of the original property with an extension that flows seamlessly into a modern, light-filled and spacious living area, through to a beautiful garden and outdoor entertainment area.
Niall was a pleasure to work with as he collaborated with us to understand our needs for a family home, set up with entertainment and working spaces.
I would definitely recommend Niall’s services to anyone looking for an architect.”
— Sharon D. and Matt C., Geelong West
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