Merchant Builders Retrofit

Wurundjeri Woi-wurrung people of the Kulin nation,
Canterbury,
VIC
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About this home

Our home for the last 25 years is a modified Merchant Builders Courtyard House. It embodies the concerns of its time – flexibility, connection with landscape and daylight.

Merchant Builders had a radical ambition to create “total living environments” for families in the suburbs. To achieve this – the landscape and interiors received the same care and expert input as the house design.

The original marketing from the company stated that “excellence in design is a combination of careful practical planning and satisfying aesthetic qualities” and that “good design [not only] doesn’t date” but is an “honest response to real needs”.

The needs were privacy, relaxation, comfort, peacefulness, harmony, sunshine and connection with the natural environment.

While our compact home was exceptional in its design – its thermal performance and durability were not!

We took a holistic approach to sympathetic restoration and retrofitting for energy efficiency.

Updating a house to modern standards involves insulation, air sealing, better windows and shading, and efficient heating, cooling, and hot water systems.

Key advice
• Set clear goals and ensure all decisions support them.
• Seek expert input.
• Specify materials and methods accurately, focusing on air sealing and insulation.
• Verify installations with thermal imaging and blower door tests.
• Plan for an all-electric home, preparing for future upgrades.
• Plan for climate change, accessibility, and electric vehicles.
• Manage moisture.
• Choose practical, timeless design over trends, especially in kitchens.
• Monitor consumption to adjust behaviour.

Our retrofit achieved 10 stars on the Residential Energy Efficiency Scorecard and greatly improved thermal and acoustic comfort.

The original designers’ aims and strategies to create a calm, light, peaceful, private and practical “total living environment” are as relevant to today’s families as 50 years ago.

Jill Haapaniemi Sanctuary Magazine

Q & A

What motivated you to build or retrofit sustainably?
Health, comfort, resilience, climate concerns, future-proofing
Ceiling insulation. The home had none. The low slope 'C' shaped cathedral ceiling roof with box gutters was a big technical challenge to insulate, and change the roof plumbing to withstand intense rainfall events yet not the external appearance of the simple Brutalist exterior. Previously when it rained it wasn't possible to hear the TV and the gutters always overflowed back into the eaves. For 9 months of the year we froze. Now the house is quiet and comfortable year round.
We should have inspected and tested the insulation and air sealing at a point that it was easy to rectify. The constraints of doing our retrofit during pandemic lockdowns meant that this wasn't possible. Even photos of the insulation installation and gap sealing would have been helpful. If a builder hasn't done a high performance retrofit before there is a steep learning curve between conventional building practices and high performance building practices.
Really happy with the outcome including persisting to achieve the in ground rainwater tank plumbed to the laundry & toilets despite discovering we have an aquifer!
Type: Standalone house/townhouse
Project: Home retrofit
Architect: Graeme Gunn (1977) for Merchant Builders
Designer: Janne Faulkner (1977) for Merchant Builders - Interior Designer
Builder: Merchant Builders
Size: 155m²
Energy Rating: Residential Energy Efficiency Scorecard - 10 stars
Bedrooms: 3
Bathrooms: 2

Sustainability Features

Building Materials & Envelope

Draught-proofing/air sealing
High-performance insulation
Double or triple-glazed windows
Recycled or reused materials

Heating, Cooling and Ventilation

Passive heating/cooling (north-facing glazing, cross ventilation, thermal mass, shading, etc.)
Heat pump (reverse-cycle) heating/cooling

Energy and Appliances

Rooftop solar PV
Dedicated wall-mounted EV charging
Efficient lighting (LED, daylighting, solar skylights)
Heat pump hot water
Electric cooktop - induction/ceramic
Other energy-efficient appliances

Water & Waste Systems

Rainwater tanks

Landscape & Biodiversity

Native garden

Climate Resilience

Heatwave

Accessible & Flexible Design Features

Design for flexible use
Design for multigenerational living or dual occupancy
Universal design for accessibility
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