An owner-builder approached us to design and document a high-performance passive solar home that used the most sustainable materials that were commercially available (in 2016) while also being simple to construct.
Our Sydney team is expert in passive solar design and relished the challenge. Hempcrete was chosen for its high thermal performance and carbon sequestration. The owner did an outstanding job using this material, creating quite possibly the most accurate formwork and hemp placement we’d ever seen. The high standard of finish he achieved was impressive.
The interior is lined and finished with materials and coatings that do not off-gas VOCs. zero off-gassing materials and coatings. All joinery is made from E0 rated board.
We deliberately chose a simple skillion roof to reflect the beach shack vernacular that once predominated here. (“Since sadly overwhelmed by mega brick veneer McMansions that look like they are trying to emigrate to upstate New York,” remarked Envirotecture’s founding director Dick Clarke.)
The site has a great north-facing aspect with a slight slope to the south and the location is bushfire-prone. Protection from western summer sun and wind protection was critical as the westerly winds are relentless in El Niño years. Harvesting the winter sun’s warmth in winter and inviting the sea breeze in to keep things cooler in summer were fundamental to the design. Windows are double-glazed in thermally improved frames, with smaller tight-sealing louvre infill panels specified for the purpose of passive cross-ventilation.
The home was designed for a growing family of teenagers, who would in time return as adults with families. The house has three main zones. The main bedroom and study plus laundry sit to the west. The open plan kitchen, dining and lounge area is located in the middle of the house offering views and access to a protected north patio plus the southern aspect which faces the street. The eastern wing houses the remaining three bedrooms and bathroom with separate rumpus room.
The house has an innovative semi-off grid septic system, rainwater tanks and an 8.4kWp PV array.
This project dates back to 2016. Envirotecture would now use Passivhaus Planning Package software (PHPP) to energy model the design, even if the project wasn’t seeking Passivhaus certification. PHPP accurately predicts energy use and people’s comfort and helps architects get the best performance for the client’s budget.
