my inlaws had a new oak floor installed a decade ago in their living room,
which is heated by a coal fire.  the floorers did it right to the lath and
plaster, no gaps, and within two years the floor had broken the plaster on
both ends of the floor.

when they reinstalled it they left about 3/8" , and put 1/2" or 5/8"
molding covering the gap.  no problems since.

i hardly think you'll have an issue from the shelves if they are on top of
the floor, even with them bolted through.  if you leave enough space at the
back of the shelves to move a bit, they can move with the floor and
subfloor.  but i am guessing rather you'd see the boards slide by (tongue
and groove i assume?) rather than buckle.

but i only play a flooring installer in a caillebotte painting...

best,
bill
felton, ca

On Mon, Jan 3, 2022 at 8:08 AM Bill Ghio via groups.io  wrote: