To create a courtyard roof, four single-sided sub-roofs need to be created individually to for the overall roof.
To make each side, select the Roof icon from the Architecture ribbon.
Once in the Roof Sketcher mode, either select the Pick tool and click on a room, to create a roof whose base takes the room's form; or, use the line tools to manually draw the roof base's outline.
Under Roof Edge Settings;
For ONLY the edge subtending a slope, define the desired Slope Angle (degrees) in the corresponding field and set the Roof Edge Visibility to 'Visible'.
For the other edges , define the Slope Angle (degrees) to 90, and set the Roof Edge Visibility to 'Invisible'.
Click on Apply to apply changes.
Repeat the process for the other three sub-roofs.