How best to retro-treat “submerged” wood fence posts to prevent rot?
Can you clear down to where the posts enter their concrete surround and then in late summer (when hopefully the timber will be dry and shrunk as much as possible) let preservative round down the four faces in the hope it will be getting into the post. Put the ‘preservatives’ sites up and see what they offer ‘Chair Doctor’ make a glue which one injects through a tiny hole and expands the end grain of chair joints, I’ve not heard of similar for preservative but it might work.
