A team of researchers at the Future Cities Laboratory has designed a new sustainable housing type specifically for rapidly developing tropical cities. The housing unit is called rumah tambah (‘expandable house’ in Bahasa Indonesia). It has specially designed foundations and a roof that can be raised so that the house can be expanded vertically up to three floors. It collects energy from the sun, rainwater from the sky and manages its own waste in a decentralised sceptic tank system. The housing type is central for the design of a sustainable Tropical Town. This pilot project was recently launched in Batam, Indonesia and the housing type may eventually be exported to other parts of Indonesia and Southeast Asia.