We moved recently. Most of the floor joists have been reinforced as shown in the pictures below. There are a few that were not reinforced by the previous owner which I would like to reinforce. This was suggested by my home inspector.

Are these floor joists properly reinforced (sistered)? If not, what needs to be done to correct these?

My main concern is that the reinforcements are not secured to the main beam on the end. The original joists do have a joint cut into them that allows the original joist to pass into the beam. The reinforcements are nailed and glued to the original joists.

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  • How are the original joists supported? I see the notch, but that doesn't hold them up.
    – isherwood
    Jul 5, 2023 at 14:18
  • @crip659, homes were build for decades with just face-nailing supporting the joists. It's not the disaster you imply. Also, answers go down there.
    – isherwood
    Jul 5, 2023 at 14:19
  • What is the problem, and the objective for reenforcement? What was wrong with each of the joists that was already sistered? (Or, apparently, all of them?) What remains wrong, and what needs to be achieved? Also in the last picture there is a post that looks relatively new. Why? I don't know if you should actually answer these questions here. It seems like there is a whole lot going on there, and you should get a qualified person to do a thorough analysis and make recommendations.
    – jay613
    Jul 5, 2023 at 15:13
  • 1
    The deep notches for wiring holes rather than removing and then replacing the wires drastically reduce the strength of the sisters.
    – Ecnerwal
    Jul 5, 2023 at 17:35
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    Given that the sisters are deeper than the original joists, I'm guessing it was done simply to improve floor stiffness, not necessarily bearing capacity. And while the top notches do reduce the stiffness some, the additional depth makes up for that (assuming the bottom isn't similarly notched).
    – Huesmann
    Jul 6, 2023 at 13:44

1 Answer 1


If the original joists have proper bearing, the sistered joists are primarily to add stiffness. They can rely on the original joist bearing for load. That bearing would need to be adequate for the load, though. Face nails alone don't meet modern standards.

Otherwise, simply add triple joist hangers per manufacturer instructions.

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