Exterior wall finish automatically by selecting walls

Hello everyone, there have many methods for finishing an interior wall, but I would like to finish the outside of the wall with window and door cuts.
I would appreciate If someone has already developed the script or any recommendations you may have for me.

Not quite sure i understand. Are refereeing to the outside face of a wall, Or the returns of the wall openings where doors and windows cut in?

Thanks for the reply @aaron_rumple,
I explain you in more detail.

Refer this image, In this image you can see the interior wall finish by rooms, But I want to get this kind of finish on exterior walls.

Something like this,

and I’m getting null value in the “Wall.ByFace” Node.

Wall.ByFace is only used with faces from a mass element.
You either need to use the geometry of the wall to make a mass and then get the faces of the mass. But that’s the long way around.
For vertical walls just het the location line of the wall as a line and use that to draw a new wall with the same height as the existing wall.
But wondering why you don’t just make a wall type with the correct material on the exterior(?) No code required.

Thanks @aaron_rumple, Actually I have lots of wall type and I want to apply the finish in some specific walls.