Attic walls on second floor?

[matdeslaurs]

Hello, 

 

I have home designer architectural. 

 

I made a room with the roof lowered in it, so the ceiling follows the roof pane. The problem is that the exterior walls don’t fill up the gap into the gabble wall. If I what it to be filled, I need to create another wall, but it appear also in the room. 

 

I know the program normally fills it automatically with an attic wall, but my situation is that I have lowered the roof and so it doesn't will with the attic wall, because it is not in the ‘’attic’’ section.

 

Do you have any idea?

Thanks!

 

Mathieu