Posts in the ground

Cut the end off? [1]

Seriously, it's much less of a problem with pressure treated timer than it used to be with untreated timber. I've got some tanalised posts which were concreted in about 25 years ago, and are still going strong. One or two got dug up last year to make way for a new garage, and the timber inside the concrete looked perfectly ok.

Hi Dave, I concreted our 3" posts in 18+ years ago and although painted with preserver at the time and subsequently with a mix of old oil etc they are now rotting, with the last gales fracturing some posts. They rotted just at ground level and not apparently lower down. I expected to just chip out the post remains and slot in another but the wood appears quite sound with initial drillings revealing sound wood.

Gio

Candle wax is probably the best sealant for end grain but IME posts in concrete mostly rot at ground level where water sits due to vegetation or soil build up. Plastic causes sweating. The post (sorry!)on here recently about setting them in gravel/cement was interesting.

Yep. That longlived and rot free species Postus Concretia Reinforcii

A traditional approach used to be to char the end of the post in a fire for a while before putting it in the hole. The charring produced turpentines that preserved the wood and the wood tars helped to keep the moisture from the heart of the wood.

Solutions I have used:

Colin Bignell

I've extended the effective life of timber fence posts by reinforcing them with angled brace posts, obviously taking space on my side of the fence. This made the post much more resistant to wind forces and has probably slowed the break-up of the fence panels.

Applying heat is a pretty good way of guaranteeing rot. The resin migrates to the end grain and leaves the interior devoid of any natural defence against moisture. A good reason for not burning paint off exterior woodwork too.

But don't the braces rot at the same rate as the posts?

Possibly, but because the design is braced there's far less stress on the original post, and as far as I'm concerned my fence posts are lasting well. (If they do go, there's a mass of shrubbery to remove to gain access for digging etc!)

Yes. But it might be a VERY long time.

No. This is wrong. The worst area is at ground level +/- a few inches. This is the area that is rich in both moisture AND oxygen. Higher up the wood dries out, lower down it becomes saturated and de- oxygenated which stops the fungi growing.

Won't make much difference (see above).

- Sloping the concrete to ensure water drains away from (not towards) the post will help.

- Using tanalized timber (not untreated) will help.

- Using oak or chestnut (not softwood) will help.

- More exotic species could probably be even more effective and solid mahogany gate posts would make a striking entrance feature.

- Concrete posts will last better than untreated softwood. I don't know how they compare with tanalized or hardwood.