Emilio Fuscaldo, founder of Melbourne-based Nest Architects, designed this brick house for himself and his partner, Anna Krien, on a small subdivided lot in Coburg, a suburb north of Melbourne, Australia. The 500-square-foot green roof of the home is much more than just an environmental statement. Water from the rooftop feeds the toilet and the garden’s watering system, while the garden serves as insulation to keep the gas bills low in the winter.