ISA's Tiny Tower residence fills leftover plot in Philadelphia

Pennsylvania architecture studio ISA has designed a slender five-storey house in a developing Philadelphia neighbourhood, as a housing prototype for tiny vacant lots.
ISA's narrow Tiny Tower is built like a mini-skyscraper, using a steel-reinforced wood frame that is clad in painted metal across its exterior. Windows take up large portions of the street facade.Each of the levels is designed to suit different functions, with the floor space totalling 1,250 square feet (116 squ