I am re-posting this because my original post had poor drawing and caused a lot of confusion.

See image below. I have a joist that is cantilevered 4' 10" (colored in cyan for quick reference), which I wish to support by a double 2x12 (or smaller?) beam which colored in purple for quick reference.

My question is: Is this acceptable? The span of the "purple" beam would be ~14', but all it's really needed for is to support those joist that are cantilevered. enter image description here

1 Answer 1


While your approach is fine, but I prefer to add an edge beam as shown red in the sketch below. Then you only need to run the diagonal in between the beams.

enter image description here

  • That makes sense. I can see how that would provide better support for the diagonal beam. Thanks! Apr 7, 2021 at 2:39
  • 1
    You are welcome. Nice drawing.
    – r13
    Apr 7, 2021 at 3:08
  • Being that the joists are on top of the beams - how would you connect that beam to the ends of the beams at the top of the drawing (where they "T" together)? Carriage bolts with a 6x6 block? Apr 7, 2021 at 3:35
  • I suggest visiting the "Simpson Strong Ties" website to find hardware for T-joint. strongtie.com
    – r13
    Apr 7, 2021 at 3:43
  • I would just jsur a double joist in the red location ans support the cantelevers at their end via the diagonaf green "fascia" beam
    – Jasen
    Apr 7, 2021 at 8:46

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