Hey everyone! I'm looking to build a 6-foot privacy fence in Southeast Wisconsin, and I need some advice. The frost line is pretty deep here, so I'm planning on digging 4-foot holes for my 4x4 fence posts. I'm curious about how much cement I'll need—if my hole diameter is between 8 and 10 inches, will 2 bags of 50-pound cement be sufficient for each post? I've heard mixed opinions on this; some say 2 bags should be good, while others suggest using 4 or more. Is there a formula I can use to figure this out accurately? Thanks in advance for the help!
1 Answer
You can use some equations to get a better estimate of the amount of concrete you need. To do this, calculate the volume of the hole and subtract the volume of the post. The volume of concrete needed is the difference between those two. It's pretty straightforward if you know the formula for the volume of a cylinder. You can even get an estimate with help from an AI if you want to save some time!
Didn't even think of asking AI! That's a solid idea; it could help with getting the volume of concrete per bag too.