[Marches Farmer]

Post is oak and has drawn up water from below the concrete layer, which has rotted it at the collar.  Fibres haven't rotted away, however.  We've tried drilling away the concrete around it but the whole area is under tension due to the fibres taking up more room than the original post.  Also tried drilling out the fibres - ditto result.  Also tried soaking the post in diesel, letting it soak in and setting fire to it - destroys about 3 mm at a time.  Only need to remove it from the hole as a new post will go straight in.  Only alternative we can come up with is hiring a pneumatic drill and taking out a big chunk of concrete all round.  V. expensive solution, though.  Suggestions welcome.

[Bionic]

MF we have had exactly the same problem. The gate posts have all rotted at ground level. OH has tried hacking the posts out of the concrete by hand but was getting nowhere. In the end, as we had about 8 to do he hired a mini digger. We have holes bigger than we would have wanted and it wasn't cheap but at least it got the job done. Metal posts are now going in 

[bloomer]

The only way I've ever done it is with a breaker and a lot of bad language.

[Big Light]

Shoot the idiot who concreted the post in and in your desperation to bury the body you will be able to dig it out no problem bury body and hide under concrete - Simples!

[bigchicken]

Explosives lol

[jjmillsy]

The only options that I can think of, is either drill the post or drill/chisel away at the concrete base holding the post. It may be easier to use a pnematic drill, however I've had great success from using a Titan SDS drill (from Screwfix http://www.screwfix.com/p/titan-ttb278sds-5kg-sds-drill-230-240v/97533). I've managed to drill holes with ease into engineering brick, chiselled off old tiles and the attached render whilst also making a simple job of breaking up an old concrete slab that used to form the step to the house.

This may be a cheaper option than hiring a drill. For £50 might be worth a go!

[Foobar]

Shoot the idiot who concreted the post in

+1

[Cosmore]

Depending on the size of your post, you could try using a post hole borer to get most of the wood out then use a long cold chisel to remove the rest.

The way to concrete wooden (tanalised of course) posts in is to first put a couple of inches of concrete in the bottom of the hole, then put a slate to size on this layer, then concrete (using a 4:1 mix) the post in on top of the slate, making a bevel water run off around the post base just above ground level. I've done it this way for years and never had a problem with the posts rotting - yet! They will probably outlast me!

[Marches Farmer]

Wish you'd done ours, Cosmore - these were put in by the previous owner about 40 years ago, so have done quite well. 

[cloddopper]

I took out the rotten teeth that had been fence posts set in concrete by digging round all twenty  or so  of the concrete stumps , once I'd got deep enough  levered the stump  up to one side using "PUDLOCK's " , (scaffold poles with a flat on one end " and back filling each hole by continually rolling the block back and forth with the levers to let me do the back filling .

I have also used a half width garden trowel fitted to a broom shaft , to chip away  hard packed clay and use an industrial vacuum cleaner to take it out the hole to get  awkward posts out between Leylandi & rose bushes etc. all done like this so I could then take out the sodding Leylandi by the same method so Ididn't wreck next doors  garden & well trimmed low box hedge 
 
Once out the ground the concrete plug is broken fairly easily with a sledge by cracking it at the corners of the former post ...so you are walloping the thinnest &  weakest part .  In later life I gave up using the sledge due to my back & shoulder injuries and so used an 650 watt SDS hammer drill with a flat chisel ..set to just hammer .

 I've also often used my power washer to blast , soak ,soften  the soil around posts  & blocks to loosen it .  By the time you're at post number five , number one is usually soft enough to dig out several inches fairly easily .
   
 Back filling holes with wet soil & a hose pipe  is a good way of  knowing you are going to be able to dig in a new post hole that is free of  rubble & bricks in a few days time if you have the luxury of time on your side.
Putting the new posts in a wet hole using a dry mix is far easier than having to cart a wet mix , the extra wet soil soon sees it " Go off " in a few days ..even less if you've added a quick set powder to the mixing .

I have also used  10 inch long hardened steel coarse thread wood  bolts with hexagonal heads and thick washers  ( screw fix on line ) to fit a loop of decent strong chain ( screw fix again )  to the top of posts in concrete and use a 4 mtr 4x 4 lever over a block of apple tree bole to jack the whole base out  after giving each "  peg " a power washing every night for a few minutes to get the soil damp low down if its been dry .

 You normally find that there is solid wood three or four inches below the  top of the concrete .

 There is an easier alternative sometimes available to you and that is to dig out the  first post entirely  back fill with very wet soil ,  then dig the other post holes to the side of the others in the run .
 Here at this property I  cut a full fence panel in half  & re-made it as a proper looking half panel ,  so I could take advantage of the virgin ground  in between the original fence  line .  This saved me having to dig out 21 rotted posts that had been set in concrete.
 I've replaced all the old fence support poles with concreted in " H "  section reinforced concrete posts and slid in new fencing panels .

Nearly  20 years ago  when making a small boundary fence about 20 inches high I capped all cut sloping tops of the short fence posts with 150 mm  self adhesive  imitation lead flashing tape . They were still all there  a year ago .


 One of the biggest problems with wooden posts is that folk don't protect the  base of the posts at the " Dew point " , where the effects of Dew & damp are to be found ....this is the first three inches below the ground and the first nine inches above it .


 Whilst in British Telecom com it was quite normal to find almost 100 yr old telegraph poles  in towns & cities as well as the countryside .
This feat is easily achieved quite cheaply , because every seven years the base of each pole was dug out to six inches down and then the whole bottom painted in creosote  up to the 18 inches point , the dug out base was then back filled and tamped down .

 The old fashioned mahogany railway sleeper farm gate posts are a bit more difficult as most were 9 or maybe 10 feet long (  ? )  & set in a four foot deep hole that was four feet round at the top and three feet round at the bottom  to which Punnered " or rammed down rubble and sometimes a very liquid concrete was added whilst it was being set up.
 That's when dad and the other farm workers dug a real big hole and used a pair of strong friendly shires to drag out the stumps on a chained pulling  harness  before back filling the crater and punnering in  yellow or blue  clay , then digging a nice new gate post hole .

[bazzais]

They can be a right pain - lots of leverage with a big pole is ideal.

No point in trying to tow it out unless its loose and you can get a good purchase on it.

When I was a green newbie - I concreted my whole campsite with post and rail with concreted in posts - 3 years they lasted before rotting and getting blown over in the wind.

If your going to concrete stuff in - put rubble in the base of the hole for water to escape and bevel the top - soak your posts in old engine oil and diesel before hand