I have a house built in the mid-70s with a second-story balcony deck that has joists cantilevered about 4 feet out from the wall. While I was replacing the deck boards and railing, I discovered some rot on one of the joists towards the outer edge. The railing post became loose during the removal process, which has me concerned about the stability of the balcony. What options do I have to repair this rotting joist? I've included some images for reference: [Image 1](https://imgur.com/a/kqElmYu) and [Image 2](https://imgur.com/a/3fa1L63).
2 Answers
One option is to sister some new joists along the full length for extra support, which will help you securely attach a rim joist. Once that's in place, you can reattach your railing posts where the joist and rim joist meet, using Strong-Tie DTT2Z tension ties for added strength. Also, don’t forget to cover the tops of your joists with butyl tape before putting down the new deck boards to prevent further rot. I did something similar on my own cantilevered balcony, and it turned out great!
While sistering is a good idea, make sure it extends back into the house for stability. You might want to remove the railing posts and assess how deep the rot goes first. If it's not too severe, you could possibly just replace the affected area and use longer bolts. I'll recommend checking the top of the joists too, and installing flashing might help as well. If you can get more pics this weekend, that’d definitely help figure this out!
Thanks! I’ll get better pics and report back on the damage.
Sistering and adding a rim joist was my first thought too. Good to know it’s a solid approach!