Loadingā¦
5
Tried a new post hole mix in heavy clay and it backfired
Last week in Springfield, I mixed a bag of quick-set concrete with some bentonite clay powder, thinking it would help with drainage in a wet spot. The whole thing set up way too fast, like in 15 minutes, and cracked when it dried. Now I have to pull three posts and start over. What do you guys use for a solid base in clay soil that stays wet?
3 comments
Log in to join the discussion
Log In3 Comments
campbell.nora7mo ago
Oh man, ericking is totally right. Concrete is a sponge that just traps water against the post. Gravel is the way to go, but you gotta go deep. I dig down past the frost line, dump in a solid foot of crushed stone, and tamp it hard before the post even goes in. Then it's all gravel backfill, tamping every few inches. Lets the water sink down and away from the wood.
7
thompson.christopher6mo ago
My neighbor's cedar posts rotted in three years with concrete. Switched to a 2-foot gravel base and they're solid a decade later.
5
ericking7mo ago
Ever think the problem is trying to make concrete drain? That stuff is meant to hold water out. For wet clay, I just use straight gravel in the bottom of the hole, set the post on that, and backfill with more gravel. It never locks in water.
2