Due to the poor conservation of domestic structures in tropical and subtropical environments, the study of households has received little attention from Caribbean archaeologists. However, recent studies have produced good quality household data in the form of post-mold distributions that can be used to address this topic. A method for the definition of houses using the post-mold data is introduced, and three cases from Puerto Rico are used to investigate changes in house shape and size through prehistoric times. These changes are discussed in the context of sociocultural and political trends in Precolumbian social formations.