ran into a similar situation restoring a house in NH once: a ~1900 house had a second story added ~1940. The second floor was sagging horribly. When we took it down to studs, we found three things. First, not enough floor beams to support the floor (and some just ‘linked’ by a nail or two when they didn’t reach the span) Second, to let heat rise to the 2nd floor, they had added registers – two of which cut right through a beam! And third, instead of a wall in the middle supporting the longest beam, apparently the beam is what was holding up the wall – the studs didn’t even reach the beam!
the house held up by the roof – bound to fail
ran into a similar situation restoring a house in NH once: a ~1900 house had a second story added ~1940. The second floor was sagging horribly. When we took it down to studs, we found three things. First, not enough floor beams to support the floor (and some just ‘linked’ by a nail or two when they didn’t reach the span) Second, to let heat rise to the 2nd floor, they had added registers – two of which cut right through a beam! And third, instead of a wall in the middle supporting the longest beam, apparently the beam is what was holding up the wall – the studs didn’t even reach the beam!