On a rubbish-filled river in Rio de Janeiro, passers-by look in awe as Luiz Fernando Barreto floats atop the home he has assembled from scrap wood, plastic and metal.

Known locally as “Luiz Bispo”, the 55-year-old, who considers himself an artist and philosopher, even has a swimming pool and van on board.

“I have an incredible personal satisfaction knowing that I built it with recycled material,” he said from inside his vessel, with windows made from old wardrobes...