There are a variety of other ways to model that junction. Some are practical, some less so!
1) Model the wall with a complex profile to the correct shape, then SEO the
wall
away from the slab.
2) Model the entire wall/slab junction with a complex profile applied to a beam. Stop the slab and walls to the edges of this beam. (A bit like this
here )
3) Use another slab (or beam) in the wall set to the same composite but without the tiles. SEO this away from the wall. Stop the main floor slab at the edge of the wall.
Option 3 is probably the simplest. I've attached a image show this solution. The highlighted element is the separate slab SEOed away from the main wall. When deselected, the join can not be seen.