The concept of sustainable construction considers the creation, rehabilitation and responsible management of a healthy built environment based on efficient resources and ecological principles contributing to social, environmental and economic balance.Indeed, in this project, the two buildings to rehabilitate belong to the nineteenth century and are located in Porto’s downtown.The floors are divided into four independent fractions where each is equipped with a prefabricated module that solves all the functional needs of housing, consisting of: a toilet, kitchen, working area or sleeping space, cabinets for storage, a drawer to bed and still room for the infrastructure of water supply and ventilation due to a building with housing overlapping fractions.This module can be applied in other rehabilitations, in buildings of the eighteenth / nineteenth century in Porto’s historic center because it has the ability to adapt to the typical dimensions of housing of this era fulfilling the technical requirements and livability of our days.