Australia's First Rooftop Garden Passive House

Seaforth Passive House

We built this innovative Passive House new build to meet Passive House principles without formal certification, prioritising healthy indoor air quality, energy efficiency, and mould prevention. The clients wanted a sustainable, comfortable home that would support their family's well-being while ensuring long-term durability and performance. Note: the windows installed are high-performance but are not certified Passive House windows.

As a pioneering project, this build also featured Australia's first rooftop garden on a Passive House, presenting unique and complex technical challenges that had never been solved in Australia before.

Our Process: From Knockdown to Completion

High-Performance Passive House New Build

BBS was responsible for the entire structural build: slab-to-cladding construction ensuring airtightness and insulation continuity, weather-resistant barriers, air-sealing to prevent moisture intrusion, and custom cabinetry and interior work designed for durability.

Engineering Australia's First Rooftop Garden

The rooftop garden required structural reinforcement as the original engineering was too light. We designed a chimney effect airflow system to regulate temperature beneath the garden, maintaining thermal performance without compromising the Passive House envelope.

PVC Waterproof Membrane and Rooftop Preservation

A PVC waterproof membrane was carefully installed and preserved to prevent any water infiltration from the rooftop garden into the building envelope below, protecting the airtight layer from above while supporting the full planted load.

Pro Clima Airtight Membranes and WRB

We integrated Pro Clima airtightness and moisture management solutions throughout the envelope: airtight WRB membranes protecting the home from condensation and heat loss at every junction.

BINQ HRV Windows and Ventilation

High-performance BINQ windows and an HRV mechanical ventilation system were installed for optimal air quality and thermal efficiency, delivering fresh filtered air to every room while recovering outgoing thermal energy.

Project Challenges

Engineering Australia's first rooftop garden on a Passive House required reinforcing the structure, as the original engineering design was too light for the garden loads. We had to ensure structural integrity while maintaining Passive House principles (airtightness and thermal insulation) throughout.

A chimney effect airflow system was implemented to regulate temperature beneath the garden without compromising the Passive House envelope. A PVC waterproof membrane was carefully preserved to prevent leaks while supporting the full weight of the planted rooftop garden.

Results: A Year-Round Comfortable Home

0.9 ACH Blower Door Verified: ultra-low airtightness result at completion

Australia's first rooftop garden successfully integrated on a Passive House

Mould-free, healthy living environment via airtight construction and HRV

Year-round thermal comfort with minimal heating and cooling requirements

Chimney effect airflow system maintaining rooftop ventilation without energy loss

Project Outcome

The completed home achieved 0.9 ACH Blower Door Verified, an ultra-low result confirming the home's exceptional airtight performance. The rooftop garden airflow system regulates temperature without affecting insulation or energy performance, and the home delivers a mould-free, healthy indoor environment for the family year-round.

“We wanted a home that would be healthy for our family and truly energy-efficient. BBS helped us achieve that while also creating an incredible rooftop garden that we love. It's the perfect balance of sustainability and functionality.”

Homeowners

Seaforth Passive House

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