here’s my dilemma: should a metal fence post set in concrete sit on a drainable material (soil or gravel) or should it be encased (sides and bottom) in concrete? when we set wood posts we make sure that concrete doesn’t get below the post and that there is always an escape route for water that gets between concrete and wood. if i follow the same logic for steel posts i expose the bottom of the steel post to potential rusting from below…. we never allow rebar to contact soil.. should we treat metal fence posts the same way?
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if its not galvernize then I say yes. but most fence post break from the riding lawnmower hitting them.
Don't know if it's standard practice but just pulled a bunch of galvanized posts on our property. Each one was exposed 3"-4" below the concrete. None of them appeared damaged, and they looked as if they had been around awhile.
Round posts?>
I never use concrete for fence or sign posts
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They'll rust through where the post leaves the concrete (upward) long before they're badly rusted anywhere else. And if there's no place for the water to drain they'll rust twice as fast.
I'd consider using the finned post anchors instead of concrete. Here's a simple one: http://www.fence-it.com/chainlink2/fittings9.htm#anchor
There are others that are like the above only with two interlocking pieces going off in opposite directions.
appreciate the feedback. maybe i'm overthinking the situation. my reasoning went like this. if i leave a metal fence post with no concrete on the bottom it would be to allow drainage. since there will be moisture around because it is an irrigated landscape then i know the very very small space between the post and the concrete will always be wet. it will be wet with or without drainage at the bottom because capillary action will wick moisture up in this narrow space. if it is always essentially filled with moisture ( albeit a very small amount) it doesn't much matter if it's open at the bottom or not.
if there isn't concrete at the bottom then the metal is also exposed to the soil environment... microbes and chemicals in the soil ... would that make the metal corrode faster?
maybe it doesn't make a difference one way or the other. we are starting with galvanized posts. i don't think i can pack gravel around tight enough to make this long 6' tall fence remain rigid against our winter winds ( which come with the saturated soils of a california winter) so i ended up doing some with drainage beneath and some entirely encased in concrete.
maybe i'll be around to dig one up in a few decades and get back to you all on this!
thanks
steve
Packed crushed rock will hold tighter than concrete, since it doesn't shrink on setting. And you can pack it with a rod it to build up actual positive pressure in the hole.
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" i don't think i can pack gravel around tight enough to make this long 6' tall fence remain rigid against our winter winds "Where I grew up, there was a gravel pit surronded by a 6' chain link set in gravel compacted. It was a good 15 YO when I left home and it was still stout. I climbed over that feence a number of times in my youth, so I'm sure it is a good way to set it up. On the other side - I have seen frost heave the crete bulbous out of the ground and take the steel with it.
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