Some recent questions on shed walls from users of the Wall plugin.
Here is a very basic example of a shed wall application:
Notice that the rectangular walls are set to "inset outside" corners and the shed walls are set to "outside" corners. It could be vice versa but I think this configuration is more common.
If you look closely at the model you will notice that the upper rectangular wall doesn't quite match up with the upper shed wall height. This is because I rounded the wall height to the nearest 16th of an inch, however there is no reason why I can't take it to the 5th or 6th decimal place if I wanted it to be more exact, it's really up to the user.
The shed wall tool and configuration is relatively new. With that being said I noticed yesterday there are some issues with the shed wall and "inside corners". I will take a look at this and rectify the situation and release another update. Having an inside corner on a shed wall is rather rare so that is probably why this managed to get past me.