Curved wall with height difference

[serge_01]

Hi,

I'm wondering how you would approach to model a wall like this reference image. The closest I've come is with Extrude along Path, but as soon as I want to move vertices in the Z-axis, the walls tilt inwards or outwards in an uncontrollable way. (It is also ok if the walls don't tilt in or outwards at all, if that gives me possibilities)
Another method I was considering is a subdivision object, but then I have trouble creating a nice bezier type curve.

Curious for your ideas.

Thanks!
 

[Jonathan Pickup]

If it has to genuinely be a wall, then you can use the walls to roof to get the wall to flow up and down but it won't allow the wall to lean over. Another possibility would be to use the loft with two rails. You create the profile shape that you want (the main area of the wall) then create two rails, one for the bottom and one for the top of the wall. You then use the loft with two rails and get that nerve surface to be stretched along the two rails.

 

this might help

 

 

[serge_01]

Thanks to @VIRTUALENVIRONS for helping me with very specific instructions for my use case. It includes wall height, curving, thickness, control points and turning into a path. His tutorial is here: 

 

Thanks @Jonathan Pickup as well for his fast response, which is also a version of the same concept. 
Hope this helps other people as well!