How to fix rotting fence post?

jennywren

We have a picket fence which was there when we bought the house 13 years ago. We had it painted about 5 years ago and I have also treated the rot on the base board that touches the earth in the front garden and it looks to be doing pretty well. However, on one of the gate fence posts I noticed that the ball decoration on top of the post looked to be rotting from the inside (I just poked at it one day and despite looking fine on the outside it was soft!). I removed the ball and the middle of the fence post was rotten and damp. I scooped out most of the rotting wood and covered it during rain but the dampness is still there so I assume there is rot all the way down and that the post is kind of wicking moisture up it? The post itself seems secure and the timber itself is good quality and sound around the edges. Should the whole fence post be replaced? Or can I dig under it and put something in place to waterproof it better?

Many thanks.

Jenny

JacobZ

Hi @jennywren,

It's fairly unlikely that water wicking up through the post is the cause of the rot at the top. It is more likely to have been caused by water seeping through the crack between the decorative ball, down into the rebate that it previously sat in. This isn't to say that moisture from the bottom hasn't contributed, but to see rot at that location, it is more likely to have come down through the top of the post as well.

I can't assess the post myself, but once rot has penetrated the core of the post, where the bulk of its strength comes from, it's pretty unlikely you can do anything besides replace it.

Unfortunately, that is a custom made, decorative post, so to match it, you would need to speak with a carpenter about matching the existing post's profile, installing a post knob such as this 100mm Post Knob H3 Treated Pine Round LOSP, then installing the new post, before painting and sealing the gap between the post knob and the top of the post.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob