Face wont scale in proportion So I've been working on this arch and I have decided that I want the bottom 50cm a little thicker, a skirting type effect. My idea was to take the bottom face, extrude it (z), scale it out to the thickness I want, level it with the original vertices and then extrude to the ground

When I select the bottom face (Screenshot 1) to scale it out, the software is deciding that the median point is off centre, I think.
 

This causes the scaled face to deform (Screenshots 2 &amp; 3).

I've scaled a lot bigger than I want in the screenshots just to show better what is happening.



Can anyone help me figure out where I'm going wrong? Or let me know of a better method of adding the skirting?

using inset, like the answer in the possible duplicate question, is not a solution here
There are many vertices in the bend and just a few at the wall side, so it seems Blender calculates the median of all vertices correctly.

Don't scale the bottom face, but the ring of newly created faces after extrusion! Set your pivot point to Individual Origins, select the ring of faces, press Shift+Z and scale them as desired.