Partial joist sistering?
I am trying to level the floor of my second floor bath in preparation for tile. The joist that runs under the subfloor has sagged over the years due to plumbers hacking at it. We had a contractor install a post and beam in the kitchen that now supports the sagging joist. Structurally the upstairs bath floor is solid, however it does follow the sag. The joist runs under the bath and continues into an adjacent attic void that would be a major pain to access. I'm thinking of sistering to the portion of the joist under the bathroom in order to level the floor instead of sistering to the entire length of the joist. Will this work or am I missing something?