PSA: I was setting my post holes wrong for years and didn't know it

I was on a job in Springfield last month, putting in a basic cedar fence. The ground was pretty soft, so I was just digging down about 18 inches, dropping the post in, and tamping. My new guy, who used to work for a big outfit out west, was watching me. He finally said, 'Boss, you're not making a bell at the bottom, are you?' I had no idea what he was talking about. He grabbed the shovel and showed me how to undercut the hole, making the bottom wider than the top. It creates a concrete anchor that stops the post from heaving up in the freeze-thaw cycle. I've been doing this for eight years and never learned that trick. Has anyone else had a basic technique they missed for way too long?

4 comments

4 Comments

williams9014d agoMost Upvoted

Yeah but who needs a bell shape when you got a whole tube of hope and some gravel, right? lol I'm kidding, I was doing the same thing for like 5 years until my brother in law ruined my perfect day by pointing out my fence was starting to look like a drunken snake. I still catch myself skipping the undercut when I'm in a hurry though, like I'm gambling against physics or something. That kid definitely saved you a headache though, or at least saved you from having to explain to a customer why their new fence is doing the limbo.

nelson.cameron14d ago

I mean, if you pack the concrete tight enough up top, does the bottom shape really matter that much?

margaret_chen1mo ago

Wow, that's a huge one to miss. I mean, I used to think just getting the post deep was enough, especially with quick-set concrete. But seeing a fence I put in a few years back start to tilt changed my mind. The whole bell shape thing makes so much sense once you see why. It's crazy how the right way can feel like extra work until you realize it's actually saving you work later.

ericgonzalez1mo ago

Man, that bell shape is a total game changer... especially up here where the ground moves so much. I always pack the concrete down real tight with a stick to push out any air pockets too. A solid base without bubbles makes a huge difference over time. It’s wild how the simple stuff can slip by for years. That kid just saved you a ton of call-backs for leaning fences next spring.