We recently uncovered an old problem in our 120 year old home. It is a broken floor joist under the bathroom. We suspect that the joist had broken during a 1950's renovation of the bathroom. The broken floor joist explains the cracks in the bathroom floor and why the floor in the bathroom and adjacent bedroom has dropped about an inch away from the wall. The cast iron tub has also become separated from the tiled wall as it has dropped a bit also. Nothing seems to have moved any further in the 5 years we've lived here.
My concern is causing more damage to plumbing and walls by having the joist jacked back up to its original position and then reinforced. Would it be better to reinforce the joist in its current position to prevent further collapse instead? There are no signs of any movement in the 5 years we've lived in the house.