L-shaped roof overhang - is there a better way?

[micheus]

mbbmbbmm, about the issue you shown in this picture...


... by considering the following steps you have in the workflow, that can be solved by applying the Shell Extrude (Normal) with a distance (offset) of 0.0. Then you add an step by using the Move Y command.
This will be OK for the Workflow 1. (because of the way the roof is not following its inclination, but the ground plane)

connect the edge ring around the house and slide the resulting loop to position

As you said you are doing lots of houses, if you want some precision in the distance from the top where the roof should "stop", I recommend you to use Inset (RMB) after select the base and side faces of the house (which can be done easily using marquee selection. This way you are going to sliding that "cut" by distance and not by percentage.