1

One of the posts for my fence rotted away underground to where the post above ground could be simply pulled out. I fixed a ring with some lag bolts to the top of the remaining post (which is about 3 inches below ground level) and used a 7 ft pry bar to try to rip it out of the ground, but it turns out that the cement for the post was connected to the foundation of the house, so it's not going anywhere.

Beneath the initial rot, the post is still strong, so I can't break it up and pull the pieces out. I can't get tools like my drill deep enough to cut into it either. Maybe there's some tool purpose-built to drill/cut into the post, but I'm sure it'd be more expensive than I'd like to take care of a single fence post. The only other option I can think of is burning the remaining underground post away, or at least enough to compromise its structural integrity enough that I can pull it out.

Is there any concern / risk with doing this? The surrounding area is just dirt / concrete -- no grass or plants. The ground is extremely dry, though the fence post has naturally absorbed a bit of water in order to rot like this. The exterior wall above the hole is stucco. There's nothing flammable except for the fence post. I presume I should be using wood/similar based fire starters rather than gasoline given the plethora of gasoline-fire-starting mishaps documented well across the internet :)

enter image description here

enter image description here

Drew
  • 163
  • 1
  • 6
  • Rotted wood is already oxidized so it won't burn - at least not well. I would recommend a chemical tree stump removal compound available online or at your local home store. – HoneyDo Jun 05 '22 at 22:39
  • 3
    The stuff shown in the bottom picture(grey box, pipe, gas line?), might not like fire too close. – crip659 Jun 05 '22 at 22:46
  • screw in a big screw and pull it out if it its holding, do not play with fire – Ruskes Jun 05 '22 at 22:48
  • @Ruskes you can see in the first image that I did exactly that, only to find that the post concrete is directly attached to the house foundation – Drew Jun 05 '22 at 22:50
  • 1
    @Drew how is burning going to solve that ? – Ruskes Jun 05 '22 at 22:56
  • By burning the wood and leaving the hole open for a new post – Drew Jun 05 '22 at 23:00
  • 3
    Home Depot has a really cheap 3’ x 3/4” SDS bit: “Bosch Bulldog 3/4 in. x 37 in. x 39 in. SDS-Plus Carbide Rotary Hammer Drill Bit”, $33. Drill out the corners first and see if it pulls up. Drill as much as you need to in order to pulverize the wood. (I know it’s a masonry bit — it’ll chew through wood eventually.) Pull wood chips out with a vacuum. – Aloysius Defenestrate Jun 06 '22 at 01:27
  • Yeah - buy or rent a bigger drill (or drill bit. or drill bit extension) is the right approach here. Particularly given the pipe and meter you show but don't think is worth mentioning is right next to/above it. – Ecnerwal Jun 06 '22 at 02:56
  • The highest risk is that you will fail to get it burning where it is. It is moist and has no easy access to oxygen. Maybe possible with patience, hot air gun and no one calling the fire brigade because of the smell. – fraxinus Jun 07 '22 at 00:05
  • _Can_ you? Sure, it's your house. _SHOULD_ you, eh... not so much! Call the fire department to be on standby before you light the match. – FreeMan Jun 07 '22 at 14:06
  • 1
    https://diy.stackexchange.com/q/169095/25178 – gnicko Jun 08 '22 at 10:23

2 Answers2

10

Drill it out.

If your drill (or drill bits, or drill bits + extensions) won't do the job, rent or purchase one that will.

Even if the gas line WASN'T right there, the heat from burning it out would damage the concrete you are evidently trying to save.

When you replace it, use concrete or heavy steel below ground, and only switch to wood above ground, if at all. While "ground contact rated" pressure treated wood is supposed to last, one suspects that overblown life claims are rarely collected on (do you have a collection of the little tags on the ends of the lumber filed away with what project they were used on to be used as evidence for your warranty claim when your 40 year lumber rots out in 20? Neither do I. And if I did, I wouldn't remember where they were in 20 years if I hadn't thrown them out in the meantime. Also the lumberyard I bought them at went out of business 10 years ago...)

Ecnerwal
  • 174,759
  • 9
  • 212
  • 440
  • 3
    One more vote for drilling it out. I have replaced several rotted fence posts leaving the concrete intact by drilling them out with a 2" forstner bit, 18" extension, chisel for the corners, and a shop vac to suck out the shavings. – Chris O Jun 06 '22 at 17:50
-1

Is that a gas meter and gas line ?

Know this: if you pour gasoline or any other flammable liquid in the hole and then light it, there will be a combustion EXPLOSION. Which will destroy your gas meter, which will destroy the wall to the neighbor and you home.

gas

The fence post was probably 3 feet deep.

1- use a 2 feet chain saw stick it vertically in the hole first *have firm stand and good grip) then turn it on and cut the remaining fence post in pieces. The chain might be EOL after that. Since the chain saw is in the hole when running, it wont jump on you.

2- now use a demolition hammer (electric is fine) to knock off the concrete in the hole, find a 24 inch or 36 inch shaft length and chisel away.

Ruskes
  • 13,635
  • 1
  • 15
  • 30
  • Can you clarify the chainsaw comment? – Aloysius Defenestrate Jun 06 '22 at 02:33
  • @AloysiusDefenestrate I used it often to deep cut the tree roots. Granted the chain might need to be replaced. You basically stick it vertically and cut. Since the OP claims to have some fence post stuck in the hole. – Ruskes Jun 06 '22 at 02:45
  • 1
    +1 for not burning things next to the gas line/meter! Not sure about the chain saw recommendation. I see where it _could_ work, but a chainsaw with a 36" bar isn't exactly cheap nor easy to yoink around... – FreeMan Jun 06 '22 at 12:19
  • 6
    I have to chime in: I don't like the _"stick a long chainsaw in the concrete"_ idea as much as I don't like _"set a fire under the gas meter"_ idea. Both seem to be potentially catastrophic. **Don't do either one of those things!** – gnicko Jun 06 '22 at 14:10
  • @gnicko nonsense, chain saw jump sideways, not out of the hole if you put your weight on it. – Ruskes Jun 06 '22 at 19:44