[cincinnatus]

I live in a building built in the 40s near Chicago and I've done a lot of work that exposed various parts of the underlying structure, and the history you describe is all over the place. The dimensional lumber in the walls and floors/ceilings are widely varied and rough, not planed to anything too terribly specific. To add further injury built on sand because we're on a dune by the beach, Which as you can imagine means things are never square or plumb :-)

I recently realized that the steel beams in the ceiling of the bar (building used to be a bar/restaurant/inn) are actually old railroad ties or something. Chicago industry baby! :-D