Hollow Cubes, w/ thick walls?

Ok, I understand that Blender creates hollow cubes from the get go, but I am attempting to create a room, doors, windows, etc… I need to show a level of thickness to the room. Is the only way of doing this by making two cubes, one inside the other, and hollowing out where the windows and doors go?

Another way is to add planes in top view
and extrude them up to form sections of walls.

I’ll have to look into how to do that later, right now I’m still learning Blender.

In Edit mode Extrude Region with E and hit Enter or LMB without moving the mouse, then Alt-S.