Rotate Navmesh so that wall is seen as the floor

How can i rotate my floor in nav mesh so that i can have a wall with the same functonality what you normaly get for a floor.
I have 6 different Ai area’s one for each axis (side on a cube)
the Ai does not switch betwean a axis, so thats not a issue.

if nav mesh is not able to do this is there any other way to do some pathfinding on a dynamic grid?