I have a 6' retaining wall and as per code, it requires railing for safety. While building the retaining wall I ask the contractor to install a sleeve every 4 to 6 feets. Now we have sleeves installed, so I can install railing after the wall is complete.

Each sleeve is in 9" diameter. so I'm planning to install 8 feet 6X6" pressure treat lumber. Once post install after 2 feet in the sleeve and 6 feet above. I would be using Reciprocating saw to cut remains 2 feet from top, keeping 4 feet for retaining wall. Is this ok?

Can I use concrete mix ideals used for setting posts and I have to just add



Is 6x6” over-killing here ?

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  • 4
    I'd firmly suggest galvanized steel (or stainless steel, but that costs more) in the concrete bolted to timber above the concrete. Timbers set in concrete tend to rot out, and are then difficult to replace. A timber bolted to steel is less prone to rot, and easy to replace if it ever does.
    – Ecnerwal
    Aug 28 at 16:01
  • There would be gravel on the bottom of the holes.
    – PowerTech
    Aug 29 at 13:39
  • Doesn't matter - concrete will wick water from the dirt being retained, through the wall, into the concrete in the sleeves then into your wooden posts, speeding their rot speed. That said, I've had 4x4 pressure treated posts buried in concrete directly in the dirt for nearly 30 years and there's rot at the top where the cut ends are directly exposed to the weather (no caps), but the bottoms are quite solid.
    – FreeMan
    Aug 29 at 18:16


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