Base extension distance causes wall joins to malfunction

[tom-common]

I am sure this must have been raised before as it seems like such a common occurrence.  However: 

Can someone explain how to stop this happening?

I have unlocked the external layer of the wall so that I can raise it above DPC level, see below:

However, when perpendicular walls meet which have this feature they do not join properly (not if the Base Extension Distance is the same for both walls), see below:

Results in this in plan view:

If you change the base extension, so that each wall has a different value, you get this:

i.e. correct joining.

Unfortunately, in elevation you end up with this sort of thing happening:

I have tried changing the material priorities within the wall, but it doesn't seem to make any difference.

Any help would be greatly appreciated.

Thanks.

[vitorbortoncello]

I suggest creating parts or modelling each layer individually for more control

[barthbradley]

Are you talking about this: 

https://www.autodesk.com/support/technical/article/caas/sfdcarticles/sfdcarticles/Base-Extension-Dis...

BTW: We model walls with base extensions in every project. We have no issues. 

[tom-common · Accepted solution]

@barthbradley - YES, exactly that - thanks.

[SteveKStafford]

If find changing the wall join to Miter allows walls of this sort to cleanup better.