I am extending an aluminium ladder by bolting the lower ends to 3" wide, 1" thick struts. I am concerned that the (6mm) bolts may split the wood when loaded.

  • 4
    There is less weight placed on the top of a ladder. If you must do this then add the pieces to the top. This sounds like a bad idea though. Find a longer ladder?
    – paul
    Sep 8, 2018 at 13:34
  • Agree that DIY extending a ladder is a bad choice. Do you only need a foot or so? (Commercial options might exist.) Or is this a big extension? Sep 8, 2018 at 14:34
  • I will be adding three feet ...
    – Omowright
    Sep 9, 2018 at 8:19

1 Answer 1


As a Structural Engineer in Training I advise to add the extension to the top of the ladder so there is no axial load through it, only shear and moment. I would recommend a minimum of a 2" thick piece so sister two 1" thick boards together nailing them every 6" together. I would advise that you match the length attached to the ladder with the length of the extension with a minimum of 12" overlap on the ladder. Add two bolts on each end with a 2" (50mm) spacing between each bolt and the edge of the ladder. Also make sure to match the rung distance if your extension is that long. Hope it works out for you!

  • 1
    Does it matter if the extension is 2’ long or 10’ long? Doesn’t size of bolt and end distance matter too?
    – Lee Sam
    Sep 8, 2018 at 14:45
  • The struts are placed butted against the first rung so this rung helps to support the weight. Distance between bolts is 5". My concern is the splitting of the wood by the bolts ...
    – Omowright
    Sep 9, 2018 at 8:24

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