Re: Sagging Floors and Cracked Joists
If the bounce is near the foundation, then repair the foundation may fix the bounce. If the bounce is in the middle of the room then sistering inadequate floor joist is generally called for. Personally I prefer using ¼" steel plate for the sistering. But as mentioned above fix the foundation first. If the utilities are through the joists that may have caused them to be weakened, and it will need to be redone. I have seem joists with nearly 3/4 of their width removed to run plumbing.
Be sure you live your life, because you are a long time dead.-Scottish Proverb