They should not float by default... Could you provide screenshots? That doesnt sound very likely to me, to be honest.

A few things you could try, that make floating items "unfloat":
Move them a bit - anything that floats will fall back to the ground if its moved.
Leave the apartment and enter again - if items arent floated to a certain threshhold, they'll snap back to the ground. So if that treshhold isnt reached, they should end up on the floor.