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Old timer told me to dig post holes deeper in clay soil. He was dead right.

Was putting up a 6 foot privacy fence in Louisville last month and hit that heavy red clay. This older guy, maybe 70, walked over and said I needed to go 42 inches deep instead of 36 in this stuff. I grumbled about it but did it anyway. Three weeks later after that big rain, all my neighbors posts shifted except mine. Anyone else run into this with clay?
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ellis.leo
ellis.leo10d ago
That 42 inches is the magic number in heavy clay alright. My dad taught me the same thing when we built a shed in northern Ohio, 8 years ago and the clay there is almost like concrete when it dries out. The deeper hole gives the soil room to shift and swell without pushing the post sideways. It's the same reason my gravel driveway needs a thicker base than what the books say, you just have to adapt to what the ground actually does instead of what you want it to do.
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kaih36
kaih3610d ago
That "like concrete when it dries out" bit got my buddy Dave, he skipped the deeper holes and his whole shed leans now.
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anthony129
That "like concrete when it dries out" bit got me too. I tried digging holes with a shovel in that stuff once and felt like I was trying to drill through asphalt. Ended up using a pickaxe for half of them and my arms still hurt thinking about it. The deeper hole thing makes total sense now, but man I wish I'd learned it before I had to go back and redo two posts that shifted. I swear that clay laughs at concrete like it's nothing.
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