The same logic applies to creating the L-shaped, U-shaped and Peripheral roofs, being that they are made of more than 1 individual 'sub-roof' joined together at right angles.
L-shaped roof: 2 'sub-roofs'
U-shaped roof: 3 'sub-roofs'
Peripheral roof: 4 'sub-roofs'
While creating the sub-roofs, define the boundary lines in such a way that the edge joining at right angles with another sub-roof set at a slope angle of 90 degrees and with 'Invisible' edge settings.