Can we talk about how much fence posts sink in clay soil after a wet spring?

Ngl, I used to think setting posts with gravel at the bottom was fine for drainage. But after doing a job near Denver last April, we dug up a 5 year old post that had dropped 4 inches into the mud. The customer showed me a photo from when it was first installed, and the difference was wild. What do you use to stop sinking in heavy clay?

2 comments

2 Comments

amy_murphy1513d ago

The Denver clay is no joke, my buddy out there uses 80lb bags of quickcrete with gravel tamped in around the base instead of just dumping gravel in the hole.

mason.mary13d ago

I hear you on the "80lb bags of quickcrete with gravel tamped" thing, but I actually see it DIFFERENTLY. My uncle did that exact method out in Colorado Springs and the posts started heaving after two winters. That clay expands and contracts like CRAZY, so concrete just locks the wood in and forces it to crack or push up. I've seen way better results with a 10 inch auger hole filled with 3/4 crushed stone, no concrete at all. The stone lets water drain away instead of pooling around the base. Plus if a post ever rots you can just pull it out and replace it without jackhammering a concrete block out of that hard clay.