Not sure if there is an easier Blender workaround, but for a 45 degree rotation, to line up the scaling around corners you can scale up by 1.4142 (or √2). This is because you're trying to scale that up to be the hypotenuse of a unit right triangle.

I would instead recommend modelling it as a flat series of planes and then extruding the whole thing up along the z axis.

Hope this helps. :)