If it is desired to intervene separately on the surfaces of a roof drawn with the roof command, the roof should be divided into surfaces.
To split the roof into surfaces:
Click the Change / Object Edit / Split Roof into Surfaces line in the classic menu , and the Change / Object Edit / Roof / Split Roof into Surfaces icon in the ribbon menu .
Click on the roof with the left mouse button.
The message "Roof Separated into Surfaces" will appear and the roof will be divided into surfaces.