The information in this article applies to:
How can I make a roof that has different overhangs on different sides?
Roofs that are automatically generated can have a Overhang set for the entire house, however, utilizing wall settings you can also change the over hang on a by wall basis.
The roof rebuilding methods mentioned above allow you to build the roof based on the current state of the plan a single time. Any subsequent changes require you to repeat the process each time you want to rebuild the roof.
The Auto Rebuild Roofs setting is a persistent setting that, when enabled, rebuilds the roof anytime a change that affects the generation of roofs is made, such as changes to exterior walls or ceiling heights.