Damage floor and I-joist are often found under bathrooms in new and older home. Plumbers sometimes are forced to cut the joist to allow for plumbing drains which compromising the strength of the floor structure. If the floor system has to be altered, the effected member (s) should be properly braced and repaired per the manufacture of the I-Joist. If the joist is dimensional wood, it should be repaired per the architect or general contractor.
Bill Collns is the author of this article and is a professional license Home Inspector serving the Middle Tennessee area.