Help with my fence repairs

[Tigercubrider]

no idea.

depends on the bloke, the hammer, the met post , and the state of the existing wood.
worst case, you have a post that relies on rotting wood to hold the metal shoe inlace.

You could try to chisel out the existing stump of the post I suppose, leaving the concrete in situ but it could go wonky easily

 

[ntb]

Trying to hammer the spike into the existing stump is a bad idea. You are very unlikely to get it in straight. The only proper solution is to chop the existing concrete out.

If you have a masonry drill, try stitch drilling out from each of the 4 sides starting with a small bit and working up through to as big as you have. Then drive a thick chisel into the line and you should be able to split it into 4 chunks. Repeat until you get deep enough.

Having said that, if you don't have the kit, find yourself a local handyman that has a concrete breaker. Sometimes it makes sense to pay someone else.

 

[Doggit]

Having done this several times, I would sggest hiring a medium size breaker with a long chisel for a day. You can get away with 18" on a 6ft post, but if it's down 2ft, then it'll not only be very heavy, you'll also have to enlarge the hole to get it out, and that'll take more concrete to fill. Postcrete goes of very quickly, and you can get the panel back in straight away, but I don't think that's a necessity for you, so you could use a dampsih ballast and cement mix, and then support the post in 2 directions till it's solid. If you use postcrete, then the instructions say fill the hole with water, and then pour the postcrete in, but I've learn to mix it round a bit as well; if the water goes in afterwards, it just takes longer to go off. If the post has broken off at the bottom, then water or earth has been collecting there, and rotting the post, so if you use concrete, put a few stones under the post to let water drain down the sides, and make sure that you angle the cement up towards the post so that water drains away. I've also started to paint bitumen for a couple of inches above the concrete in case the earth moves around the post over it's lifetime.