Wall joins

[markkibui101]

I have two different wall types, one goes up by 200mm, the other goes up to the roof as I've shown in section view below.

I want the top wall to reach down to the floor so as to add my 2D details as I have shown below.

Once the base-offset for both walls is at 0, the bottom wall disjoins and I cannot join them and it appears as below (Plan View)

How can I fix this?

[ennujozlagam]

drag the blue dot?

[markkibui101]

This does not work.

[ToanDN]

Disallow join the two walls, stretch and join geometry manually.

[markkibui101]

I used beams instead of walls to get around the issue.