We know that walls which meet at intersections will automatically clean up. This is especially the case when the layer’s Structure and Material assignments are the same.
The same cannot be said when walls meet other elements like ceilings, but clean ups can be forced.
- Allow sufficient overlap of the Ceiling over the Wall, typically to the core of the Wall.
- Then use the Join Geometry tool to join them together.
Where the materials are the same they will join seamlessly.