Replacing fence posts

[peterchichester]

I'm having some rotten wooden fence posts set in concrete replaced. As I am about to have a root canal at the dentist I was wondering why fence posts are not replaced in the same way? I.e. drilling down to remove the base of the post. At least you would know the hole is in the right place and vertical and you wouldn't have to chip out the concrete. Could you not get a slurry or resin down the hole to fix the new post.
There is probably a good reason why this isn't done, just wondering what it is.

 

[footprints]

You can have implants

http://www.metpost.co.uk/mp_repair.html

 

[peterchichester]

Hope my dentist doesn't do anything like that.
It's actually a serious question. It would appear to be easier to use the old holes but people seem not to. Why is that?

 

[footprints]

Just impractical. you would only get a tiny bit of cement down the sides, if you poured it in first the post would simply not push in. It's a pig of a job cleaning out old holes fully too.
I have had a go once, I broke up the old stuff (took forever) the hoovered the hole out with a Henry, put the post in and tapped folded alli sheet as wedges in to secure it. Sort of worked but really it was just a temp fix till I replaced the lot.

Maybe if you can find a cheap and quick way to remove the old stuff and a cement that is the consistency of water that can be poured in, or an expanding post we might see you on Dragons Den, but I suspect the answer would be too costly "I'm out"

 

[peterchichester]

Ah ok, pity though.

 

[ladylola]

To be honest I've reused the old concrete hole loads of times. Sometimes it can be a fiddle but sometimes it avoids damaging surrounding areas. Saves mauling bags of broken concrete away too.

 

[peterchichester]

LadyLola, how do you fix the new post in the old hole?

 

[ladylola]

To be honest on most of the ones I've done there hasn't been any need for additional fixing. Posts are normally 3" or 4" and new posts are generally a snug fit and can be knocked in quite easy. Using wood as dry as possible will help of course as it will expand in the hole. Very occasionally a thin wedge may be needed and slate is good for that . I've never been called back to redo a fence done this way. On one job this method didn't work so I chopped out one side of the concrete which allowed me to slide the post in and then concreted the new hole.

 

[Jackrae]

Metpost also do a version with an end designed to be concreted into an existing concrete pocket (once you've removed the rotten wood)
http://www.metpost.co.uk/mp_prod_selection.html

 

[davembk]

I am fully of the view that it's best to replace the whole structure. I am currently replacing a panel fence with featheredge. Not being dependent on the 6' span, I can plan where the posts go, avoiding any old locations. I'm concreting all the way up but even so, not convinced how long it will last. Was curious when I dug up an old post and saw that only the first six inces of the hole was concreted, with a rotting post at soil level. Why did they do that? So now with all concrete, mounded up to above ground level, and some ballast at the base for draining, we'll see. I've read and been told that timber treatment is not what it was.
For a quick temporary shoring up of rotting posts, and with no access to next door...a combination of a strut at 45 degrees, for oncoming winds, and alongside, a guy rope/anchor for outgoing winds. I did this a year ago, still ok although the posts are slowly getting shorter

 

[JohnD]

concrete posts, and spurs, don't rot.