What's the best method for securing metal fence post?

August 17, 2006 7:35 AM

DIYFilter: I'm installing a chain-link fence. As our winters are cold, fence post tend to get pushed out of the ground. What's the best method for securing the post?

I've seen fence posts anchored deep with concrete pushed a foot out of the ground.

Would it be better to simply hammer the post into the ground, so that I can bang 'em back into place every spring?

How deep?

Our average temperature in January is -20 C / -4 F. In the pre-spring we often get a few thaw-freeze-thaw-freezes.

posted by stungeye to home & garden (9 answers total)

The best method is go to 1-2 feet deeper than the frost line. Find out what the building code in your area requires for fence posts, and to be conservative, add a foot to it. Of course, it could be that your municipality has underestimated the frost line depth. In that case, add two feet.

Really, that's about all you can do.
posted by Merdryn at 7:44 AM on August 17, 2006

FYI: The frost line in, say, most of Minnesota, is 4 feet down.
posted by Merdryn at 7:46 AM on August 17, 2006

FWIW if you don't anchor your posts with concrete, then when you start stretching the chain link they're liable to deflect, if not during the install then later. I wouldn't think just hammering themin with a sledge will cut it.
posted by Pressed Rat at 7:57 AM on August 17, 2006

Unless your ground is actually moving or your building on permafrost a splayed hole sunk below the frost line filled with concrete shouldn't move. In Winnipeg the frost line could be pretty far down.
posted by Mitheral at 8:02 AM on August 17, 2006

There are apparently auger companies that will come just to drill your fence post holes with a big auger. Which is most of the hard work. Then you just pour the concrete. Or most tool rental places will rent augers that will go down more than 4 feet.
posted by GuyZero at 8:06 AM on August 17, 2006

You have to anchor with concrete. The movement for the fence will be more than you want to deal with, and rehammering chain link posts will eventually compromise them. Personally, I would go 18 inches below the frost-line with sacrete or another hard, stable concrete on a 16-18 inch radius around the post. Good luck, that's some awfully hard work.
posted by mrmojoflying at 9:44 AM on August 17, 2006

I have always dug about 30 inches down, then taken a small hand spade at the bottom of the hole, digging sideways all around to make the hole rather bell shaped. This was in a quite cold climate, (Wyoming) and I never had a problem with posts pushing up out of the ground. Good luck, you do have quite an undertaking on your hands.
posted by scottymac at 6:23 PM on August 17, 2006

If you want to "overdo" it, you can also take four 36in pieces of 1/2in rebar and drive the rebar into the soil another 18 inches in your post hole, effectively anchoring your concrete slug.
posted by mrmojoflying at 4:02 AM on August 18, 2006

Thanks all!
posted by stungeye at 4:33 PM on August 21, 2006