enter image description hereA stair and landing was incorrectly built without a drip edge over 4 cantilevered joists coming out of the building. Over the years, water got in and rotted the joists to just past the point where they rest on the top plate of the wall. The top plate is rotted as well.

I have opened up the outside wall and cut back the rotted part of the joists, which went just past the top plate by an inch or so. The rest of the joists all seem fine.

I will have to rebuild the top plate and sister the joists. Since only the last few inches of the boards were affected, how far into the building do I need to sister the joists if I don't cantilever them again? I've seen some say 3 ft. is enough.

Should I sister both sides, or will one side do?

Also, do I need to glue them together? And, should I nail, screw, or bolt them? I have seen people advise to do each method.

If I do cantilever them again, I believe I have to go 3 ft. in for every ft. out, correct?

  • 1
    How about a few pictures so we can see what you see.
    – JACK
    Sep 24 '20 at 18:14
  • How far do you expect to extend the cantilevered section? Some locations only allow 2’ without an engineering stamp. The last one I did similar to yours I used 3ea 8’ 2x10’s for a 2nd wide landing and that passed inspection. The inspector said if I would extended any further he would not have allowed it it was 6’ above grade.
    – Ed Beal
    Sep 26 '20 at 16:38
  • A little over 3 ft. Sep 26 '20 at 22:07
  • The original was 4ft. I may just frame it up inside, close the wall and build a deck like platform bolted to the ledger board and supported from below. Also, As I was taking out the insulation I found 5 wires running through the joists bringing power to the 2nd fl. I would need to put a key hole notch in the sister joists in order to slide them over the wires and I'm afraid that would compromise the joist. Sep 26 '20 at 22:18

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