How to crop away wall angles with different thickess

[HeadbuttJ]

I created a floor plan with thick wall as below, how can I crop away the surplus part of the walls with current desired shape? 

If I draw the walls with joint status, the turning angle shifted upwards.

How can I solve this problem? Many thanks!!

[syman2000 · Accepted solution]

I would unjoin the vertical wall. That way the angle wall will join properly with the horizontal wall in the middle. Then use join geometry to join the wall.