Remove wooden fence post 'stub'.

[Brian Reay]

We've got wooden fence post stub which is set in a sizeable concrete lump. It is broken off 'flush' at the surface- a lorry hit the fence.

Obviously I could break up the concrete etc but, owing to a hedge, that isn't a pracical option. Plus the concrete lump is large- I put it in in about 2001 and I'm sure it is at least 18", even 24" deep- I wanted the fence to be solid. (Another part stopped a 'run a way' car a few years ago.)

Even though the post was 'tanalised' and soaked in preservative before being inserted the stub seems to have deteriorated- how far 'down' I don't know.

A 'meta post' insert or similar isn't really an option, not man enough, nor is another hole due to access issues (the hedge).

I'd like to remove the stub and 'slide' a new post into the existing hole, partly due to access issues and also as the post has been hit more than once. (No not by us!)

I'm considering:

Drilling and breaking it up.

Drilling and inserting something I can 'pull' via a jack etc.

Burning (not favoured- it is by a, quiet and private, road but still a road, and a hedge).

Has anyone any other ideas?

[Tim Lamb]

In message , Brian Reay writes

I think this question has been covered earlier.

In soil, probably only the 6" above and below the surface

Tricky if it goes the full 18"

Hmm.. anything threaded is going to expand the stub and grip tighter.

I have wondered about the oxidisers used for glass fibre resin having seen what they do to cleaning rags.

Gouge out as much as you can and make sure the replacement is rot proofed and a sledge hammer fit.

>

[Clive Arthur]

I wonder if straight hypochlorite bleach or strong hydrogen peroxide would work? Obviously, holes would help, as would time.

Cheers

[Tim+]

Thermite? ;-)

Tim

[Clive Arthur]

Or termites.

Cheers

[David]

I think you should revisit your "not a practical option".

From bitter past experience I suspect that trying to replace the wooden post without replacing the concrete is going to be a thankless task.

One of the major benefits of sinking a new post into new concrete is that the wet concrete bonds to the wood and grips it tight.

Getting new wood in which also has a strong bond is non-trivial and you would either have to enlarge the hole or use a thinner post to be able to get something between the new post and old concrete for a firm grip. You also have the problem of all the bits of half rotten wood which are bonded to the concrete inside the post hole.

In the past I have dug down one side of the concrete lump then levered it into the hole. It is then relatively (!) straightforward to break it up into pieces small enough to move.

Consider trimming/pruning the hedge to make access easier. It will look ugly for a while but hedges usually grow back.

Cheers

Dave R

[Brian Gaff]

Some form of acid? Then bring out the gunk into some safe receptical. Its probably illegal now though. Brian

[FMurtz]

ANFO

[Martin Brown]

Drilling it with the largest long drill bit you can find and loading the holes with dry potassium nitrate and then keeping the rain off for a while. Wait until the driest day in mid summer and set well alight. With a bit of luck it will smoulder away slowly into the ground.

I have taken out big tree roots this way. Although chicken of the woods fungus also helped with that too. Seemed to like high nitrate wood.

It will expand the wood an bind it tighter.

It will be too damp to burn out but you might get it to smoulder. You may well have to smash the concrete to get it out.

Wait a very long time and it will eventually rot away.

[Huge]

[26 lines snipped]

Good luck buying that these days.

[www.GymRatZ.co.uk]

That'd be the southern Irish version to be sure.

[Dan S. MacAbre]

Thermite mixture? :-)

[Chris Hogg]

Break up the concrete using the expansion characteristics of quicklime?

I've never done it, but AIUI you drill some decent sized holes* down into the concrete, fill them with quicklime and tamp it down a bit, pour in some water, plug the hole with a bit of broom handle or whatever, and leave it to do its thing. Or just plug the hole without adding the water and let the quicklime hydrate from the ambient moisture. As the quicklime hydrates it expands, relentlessly, and eventually splits the concrete or rock it's in.

Google throws up several links to commercial expansive mortars and patents, the latter seem to be based on quicklime with other additives, e.g.

But quicklime is nasty stuff. You need to take care when handling it not to get it on your skin and definitely not in your eyes as it's potentially very caustic. It also gets hot and may boil in the hole, so take care to avoid it splashing and spitting out onto you.

*what's a decent size? Don't know, but getting on for a couple of cm diameter I guess. SDS drill? Mind you, if you've done that, the concrete might be easy enough to break up by hand.

[Dan S. MacAbre]

I don't know if you want to get the lump out of the ground, but I got one out by rolling it around (I was able to stick a scaffold pole I'd found buried in the garden into the hole), and pushing soil underneath it as it was moving about. Didn't take very long.

[Chris Hogg]

Builders' merchant or a firm that supplies lime mortar?

[Martin Brown]

It should be in most garden centres as fertiliser. Or Amazon:

eBay might well be cheaper. Sodium Chlorate is much harder to obtain.

[stuart noble]

A post shoe and rawlbolts for me

[ARW]

Let the lorry diver fix it.

[Adrian Caspersz]

If you can drill a 50mm hole (long Auger?) then a short length of scaffold pole could sit in it, and then you'd hollow out the new post to conceal that.

Alternatively, one of these might get the wood out, after mushing with various chemicals.

[Chris Hogg]

Hmm... I don't recall ever seeing it pure, certainly not recently, mostly it's compounded with other NPK elements into a general fertiliser.

That does surprise me, bearing in mind it's a major ingredient in an easily-made explosive often used in quarry blasting.