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Hot take: I thought a 4-inch post hole was fine for a 6-foot privacy fence in clay soil, but a storm proved me wrong.

I did a job in Springfield where the client wanted to save money, so we used a 4-inch auger for the posts instead of my usual 6-inch. A big wind storm last month knocked over three sections because the posts had no real grip. Should I have just walked away from the job, or is there a way to make a smaller hole work in tough dirt?
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3 Comments
laura_black31
Was it really the size of the hole, or what you filled it with? In heavy clay, a 4-inch hole can work if you pack it with concrete all the way around the post. The problem is usually not enough concrete, or just backfilling with dirt. The storm just showed the weak spots.
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paul346
paul3461mo ago
Right, because nothing says "solid foundation" like trying to cram concrete into a hole the size of a soda can with a shovel. You'd need a magic wand to get that packed right at the bottom without leaving a giant air pocket. Maybe that's the secret tool everyone's forgetting to mention!
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grant.sam
grant.sam1mo ago
But how do you pack concrete properly around a post in a narrow hole? Seems like it would be tough to get it solid without big air gaps, especially down at the bottom.
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