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Re-sinking 3" fence posts.

Postby TheDoctor46 » Thu Apr 28, 2011 9:47 pm

Usual story I'm afraid.

3" fence posts sunk directly into concrete. Rotted to the point of breaking at ground-level; the material under the broken post is (predictably: as per sods-law) pretty solid. Had a go at excavating the remaining post material with chisel/crowbar and mallet... no chance. Remaining option is to do it properly and completely break the concrete away and re-sink the posts with either Metpost and/or concrete.

The concrete is an "isolated lump" sunk into soil surround. It's stood the test of time so one assumes it was of adequate size and suitably anchored on a hardcore base.

Anyway, basically I'm just asking the pros here who've done this a million times before for their thoughts and for any tips on removing this sort of concrete. Should I just dig the surrounding soil away for the concrete and slug it out with the hammer and chisel?

My tools are club hammer, a variety of masonry chisels, and a fairly light-headed (2-3KG at a guess) but long-handled "sledge-hammer" that can deliver a fair clout.

Ideas and tips appreciated. Tips on how to break concrete in general welcomed.
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Simply Build It

Postby TheDoctor46 » Fri Apr 29, 2011 7:22 pm

Bit of an update. I dug the soil away from the concrete on two sides, the concrete is an absolutely solid block. Over a foot square, and well over 2 foot deep. I never found the bottom of it.

Don't really know what to do. There's no way I'll be able to break all that away, and I've got several posts that will all be the same.
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Postby drcswalker » Thu May 12, 2011 12:18 pm

Can you not just remove the rotten timber and re-use the concrete? Or can you not hire out a pneumatic drill from somewhere? Or a very low tech method of burning a fire on it/around it, quenching it with water then taking to it with your hammer and chisel?
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Postby couchie » Sun May 15, 2011 3:30 pm

When I was in the buisness even the most stubborn footing would sucumb to two long bars, one either side, maybe with a pivot under them. Just lever away & it should pop out like a tooth, then hopefully leave you not having to dig a hole.

I suppose the only problem with this woud be the need of an extra pair of hands for half an hour.
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Postby chris_on_tour2002 » Sun Jun 05, 2011 10:30 pm

i was faced with a very similar situation last year, had 6 posts to remove from concrete foundations for a 6 course brick wall with panels on top. the posts had been placed before the footings were poured.

i was able to remove a rotten stump with a long auger bit. i drilled out as much material as possible from the middle of the stump then rammed a crowbar down the side between the timber and it's concrete casing. the timber gave way and i was able to pull it out in chunks. still took a while though.

unbeknownst to me at the time though was that my biggest problem was yet to come! after laboriosly removing all the rotten stumps from the concrete i looked forward to the easy bit - just neatly dropping the new 3 inch posts into the existing holes. ohhhhh no, like it was going to be that simple.

some were to big for the holes, so had to shave them down. others too small so had to pack out with post mix and wedge it home with a screwdriver!

in hindsight might've been easier to rip out the conc. there's no easy way of doing it no matter how you choose to tackle it.
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