Often time when doing my New Jersey home inspections, I come across work that has been inadequately repaired, due to termite activity, and not up to the proper building code standards. In the photo that I took here, there has once been extensive termite damage to the floor joist system. The horizontal sillplate was repaired properly using wolmanized lumber and appears to be quite adequate, but the new floor joists have not yet been properly sistered/joined or supported to hold up the living space.
Merely nailing a short length of the new joist to an original joist does not constitute an adequate repair. These joist will separate in due time, leaving the new joist doing absolutely nothing nad hanging in mid- air. What should be done is to extend the new floor joist(s) end to end so that both ends rest on two proper bearing points or plates (as they are called in the trade). In doing so the new joist(s) will than be properly installed and ready to except the weight of the floor system and any live loads that will prevail during normal everyday use.
When it is not possible to extend the new joists from plate to plate, I always recommend installing the longest length of joist possible and than sistering (joining together side by side) the new floor joist to the original joist as securely as possible. During any floor joist repair, I would definitely recommend the use of carriage bolts through both floor joists to ensure adequate repair.