Timber treatment for below ground

[glassescase]

what environmentally friendly treatment can I use to treat timber that's below ground?

glassescase

[dewaltdisney]

I wrapped plastic bin bags around the base of a wooden fence post. It rotted around the neck as water penetrated just above where the plastic ended. I had routed a channel and sealed the bags into this with a cable tie and mastic. But some time on, the post snapped anyway at ground level in some strong wind and when I dug it out the bottom of the post was sound. I had had enough and I bit the bullet and dug in new concrete posts and reran the fence.

DWD

[Rorschach]

You can't stop rot with environmentally friendly methods. It's like trying to stop and infection without killing the bacteria.

You need to create a hostile situation that resists moisture and microbes. Of course some are worse than others, but nothing is totally environmentally friendly.

[glassescase]

I found this but not available in UK as far as I can tell
https://www.homedepot.com/p/Wolman-5-ga ... /204746309 but don't know if safe for below ground, US rules may be different to ours.

if I change from environmentally friendly to legal, is there anything, or am I destined to have to replace every few years?

glassescase

[kellys_eye]

Engine oil. Environmentally friendly??? Well it came from the Earth and it's going back in the Earth, I call that friendly....

I've heard (potentially seen) some heat shrink tubing system for protecting posts - could be rather expensive though.

[steviejoiner74]

old engine oil.
The problem nowadays is the quick grown cheap spruce that’s used for posts,it’s never going to last long no matter how much you treat it.

[Grendel]

Steve's right about the type of timber. I've encountered oak posts that are several decades old but also supposedly pressure treated posts that have turned to rot in old five.
Timbers were sometimes charred on the outside prior to going in the ground and either used as such or stood in preservative while still warm as it supposedly sucked up more .
There's also the debate about concrete or not. One train off thought is to pack with sand and gravel which allow water to drain rather than sit there as it might with concrete . I'm not sure about that last one although it's perfectly possible to get a solid job without concrete and when it does eventually rot it's easier to remove.
My father used engine oil often mixed with creosote . Probably most of his generation did. He also painted the fence with that mix . Thirty years on and if I touch it my hands still come away black.