Posts and Crash Barriers

Yes. Its on you tube and it works

I have a

Yes.

When I tried the same thing I found that nails had been driven in at odd angles to stop the posts being pulled out of the concrete, so I would have needed a suitably large tubular hole cutter to cut through the nails.

I'd imagine if you did that it might actually crack the concrete to some extent. I too heard of this technique, but feel they are not really substantial for fences depending on the wind loading of course. Brian

why not? There's expansion forces, and there's foam strength. But it sounds like you'e little to lose. For complete post installation there's now a foam product you can buy. I doubt it would be suited to sticking posts into existing concrete.

NT

I have done the "chisel out" thing for one post hole - it was hard work & took a few hours. I used a sturdy metal tube I had lying around (I think an old curtain pole or similar) and hammered it as far as possible (typically ~ 5cm) into the trapped wood, then pulled the pole out, so removing a cylinder of wood; then repeated. One it was mostly clear, I chiselled the remains stuck to the inside of the concrete. This was also hard, owing to the confined space inside the concrete (if I'd had a really long chisel-like tool, this step would have been less hard).

The wood wasn't rotten all the way down, only maybe 5cm at most, even though it had rotted through at ground level; making it much harder to do than it at first seemed. If I had to do another one, I'd probably do it faster - though I'd guess it'd take at least an hour, even with practise. A larger diameter tube would have helped, but you wouldn't want it to break and get stuck.

#Paul