In a first phase, it was carried out a historical study on the evolution of the plain roofs along the history and its pathologies. In this study, we could note the advantages and disadvantages of different models of plain roofs.

With the conclusions drawn from the study, it was developed this second phase: the construcion of a plain roof, a project that pretended to avoid the greater part of the shortcomings observed in the first phase.

It is considered for such a case, that the model of inverted plain roof is the one that gives more optimum features for the concrete example selected.