Cake House

Solution

Symes retained the triangular footprint as an homage to the iconic structure, expanding its form to accommodate two new bedrooms and protect against potential sea surges. An open balcony crowns the addition, extending from an indoor-outdoor living space that spills toward the beach via broad steps, blending house and coastline.

Despite its compact floor plan, the redeveloped house now sleeps up to 17, including a children’s bunk room that accommodates seven. “They wanted somewhere low-maintenance and relaxed – a great place to cook for friends and accommodate large groups,” explains Symes.

To meet the owners’ sustainability goals, Symes incorporated continuous insulation, high performance glazing, and a heat recovery ventilation system. These measures – central to Passivhaus design – bolster energy efficiency and improve indoor air quality. A covered outdoor area sheltered from sun and wind further blurs the line between inside and out.

In alignment with the project’s sustainability ethos, many original materials were repurposed. The blackbutt and spotted gum windows and doors were supplied by Architectural Hardwood Joinery (AHJ), a carbon negative window and door manufacturer that uses only locally recycled native hardwood timbers. “We only know one way of making windows and doors, and that is using recycled native hardwoods,” says Barry Bradley of AHJ.

Bradley highlights AHJ’s commitment to carbon negativity as a major differentiator for eco-conscious clients choosing building materials. AHJ operates on a 99 kW solar PV system and uses a 121 kWh battery to store energy for shoulder periods. Any surplus energy is exported back to the grid to help reduce reliance on fossil fuel generators. Additionally, by sourcing recycled timber within a 20 km radius rather than transporting new timber from hundreds of kilometres away, AHJ significantly reduces the project’s carbon footprint.

Recycled timber also serves as a long-term carbon store – keeping carbon locked in the wood for another 50 years or more—and spares living trees that continue to absorb CO₂. Moreover, because AHJ’s recycled timber is air-dried, the kiln drying process (a CO₂-intensive step for new timber) is eliminated. Taken together, these measures reinforce AHJ’s carbon negative status and align with the sustainable objectives of the Cake House redevelopment.

A cornerstone of the project’s efficiency is the AGG Insulglass LowE  Advance^® Double Glazing integrated into AHJ’s recycled hardwood joinery. Architect Alexander Symes explains: “The glass from AGG is amazing. The LowE glass has a high visual light transmission of 71%, so it’s super clear, yet has a low solar gain coefficient of 0.35 (SHGC, glass-only).”

Key Benefits:

• Energy Efficiency: U-Value of 1.3 (glass-only) reduces heat transfer, bolstering thermal performance.
• Solar Control: A low solar heat gain coefficient cuts cooling loads.
• Visual Clarity: High light transmission ensures ample daylight without sacrificing solar protection when needed.

“It’s about creating a seamless interface between inside and outside while delivering strong environmental performance,” Symes notes. AGG’s glazing solution was essential in balancing coastal views with climate control.

By blending Passive House principles, recycled hardwood joinery from a carbon negative manufacturer, and high-performance glazing, the Cake House has been transformed into a sustainable and relaxed seaside haven that remains faithful to its heritage. Symes summarises: “It’s synergy between performance and respectful use of resources – delivering something delightful and enduring for generations to come.”

For more information on Insulglass LowE Advance^®, click below: