The construct ion of military bases in Spain, used by Spanish and American soldiers, has brought an urgent necessity for housing to accommodate American soldiers who arrived in Spain with their families. In 1965, the US completely built 300 prefabricated houses in the USA which were then shipped to Spain and erected in Rota by the Navy ‘Seabees’, in the neighbourhood of Las Flores. In only 23 weeks, the houses were fabricated, and in a few months, they were erected. This neighbourhood had been in use for 40 years until it was demolished a few years ago. It is an unknown and interesting example of balloon-frame structure housing in Spain. The aim of this article is to analyse the design, distribution, construction and assembly process of prefabricated housing in Spain.