Wood fence posts almost never rot in mid-air or deep underground where oxygen is scarce. Over 90% of wooden posts fail in a narrow 6-inch danger zone: right at the groundline soil-to-air interface.
The 3 Rules of Rot Prevention
- Never Encapsulate the Post Bottom in Concrete: Always add 4 to 6 inches of coarse drainage gravel at the very bottom of the hole so trapped rainwater drains away freely into the subsoil.
- Crown the Top of the Concrete Collar: Trowel the top of the wet concrete into a smooth dome sloping away from the post, shedding standing water.
- Use Bitumen Heat-Shrink Sleeves (Postsaver): Shrinking a heavy bitumen barrier around the groundline interface creates an impenetrable seal that prevents fungi from contacting the timber.
