When a growing family needed extra living space, they turned to Australian design studio Steffen Welsch Architects to create an eco-friendly extension for their California Bungalow home. For the main construction material, the architects used rammed earth — a material with low embodied energy and high thermal mass — and created an arced extension that curves to capture warmth and light from the sun. Passive solar principles also largely dictated all parts of the design process, from the zoning and layout to the material selection and building form.

curved home addition attached to white house and a child running through a hallway with rammed earth walls

Located in Melbourne, the family home and extension — nicknamed ‘Down to Earth’ after its rammed earth walls — was created for a young family who enjoy entertaining and hosting guests. As a result, the brief called for low-cost operation, evolving privacy needs and future accessibility. Spanning an area of nearly 2,100 square feet, the single-story home is organized into four zones: an area for children and guests, a master suite for the parents, communal rooms and transitional areas. Each “zone” opens up to its own outdoor space.

living room with dark couch and doors opening to a wood patio

father sitting at a desk and holding a child

To ensure long-term sustainability and to minimize embodied and operational energy, the architects let passive solar principles guide the design of the building and chose materials with low embodied energy, such as rammed earth, and energy-saving properties, such as insulated glass. Operable windows allow for natural ventilation while the rammed earth walls and timber posts are left exposed to create a connection with the outdoors.

Related: Modern rammed earth home embraces the desert landscape

white bathroom with rammed earth walls

father and son brushing teeth at bathroom sink and mom and child talking next to a dark wall

“A well performing house extension facing south on a small inner city block built in rammed earth is not easy to achieve,” the architects noted. “The building uses the formal language of a Californian Bungalow with the combination of heavy and light materials and generous roofs without copying it. Rammed earth walls appear free standing and separated from a floating roof with wide overhangs providing shade in summer but letting winter sun inside. The house (including the old) achieves an energy rating 3 stars (6) above target.”

+ Steffen Welsch Architects

Photography by Rhiannon Slatter via Steffen Welsch Architects