mcablard

The exterior wall is missing the siding when I adjust the ceiling heights and would like it to be completely covered.  When I build a roof, part of it is obviously covered by the roof but the portions that are not are still exposed and not covered by siding.

I'm trying to create a layout with two rooms adjacent to each other with different ceiling heights.  I divided the rooms with the "Room Divider"  tool and set the larger room to have a ceiling height of 15' and the smaller room to a 9' ceiling height.  Would any know how to get the exterior walls to not look like the attached picture when the ceilings are changed or another process to ensure that they do not look like that?

Thanks!