Am I the only one who thinks the 'always use a 6x6 post' rule for corner bracing in heavy clay is overkill?

After a 40 mph windstorm in Omaha last spring took out a neighbor's 'properly' braced cedar fence but left my 4x4-braced section standing, I'm convinced proper concrete depth and a wider hole matter more than just post size. Anyone else have data from a specific job that changed their mind on a standard practice?

3 comments

3 Comments

dylan_smith3620d agoMost Upvoted

You're right about concrete depth and hole width being key. I've seen 4x4 posts hold up fine in clay when the hole is dug bell-shaped at the bottom for a wider concrete base. The rule of thumb misses that the soil's grip on the concrete mass is the real anchor.

ross.kevin18d ago

Yeah, the soil grip is huge like you said. I did a bell shape in my own clay soil and it made all the difference, even with a shorter hole. Simon's point about depth is fair, but that wide base really locks it in place.

the_simon20d agoMost Upvoted

Disagree on the soil grip being the main anchor. That concrete bell can still lift if the post itself isn't buried deep enough to resist leverage. You need both depth and mass working together.