Unpopular opinion: I think using a 4x4 for every corner post is overkill in some soils.

I was putting up a basic privacy fence for a neighbor in a new subdivision here in Springfield. The soil was that heavy, dense clay they have out by the new park. I figured it was tough stuff, so for the first two corner posts, I went with the standard 8-foot 4x4s and set them in concrete like always. On a whim for the third corner, I used a 6x6 post instead, thinking more mass would be even better. When we came back after the concrete cured, that 6x6 post had actually shifted slightly, while the 4x4s were rock solid. I think in that wet clay, the bigger hole I had to dig for the 6x6 just never packed as tightly, and the concrete didn't bond as well to the wider post. It made me wonder if the standard advice needs a soil check first. Has anyone else found that bigger isn't always better for post stability depending on the ground?

2 comments

2 Comments

charles_henderson11d ago

Remember reading about a guy who lost a whole garden fence in sandy soil because he used concrete. The water just drained away and left a brittle shell that cracked. Sometimes the standard fix fights the ground you're working with.

amy30211d ago

Yeah, that "standard fix fights the ground" thing is so true. I had the same problem with a post in pure sand. I ended up using a mix of gravel and dirt to pack around the base, almost like making a really solid dry pack. It lets the water drain but still locks everything in place. That post hasn't moved an inch in three years, even with some wild storms.