Free Sample
The Complete Handbook of Fence Posts & Rails
Professional selection, installation, maintenance, and business strategy for residential and commercial fencing
by Alumigogo Books
Chapter 1: Understanding Fence Posts & Rails
A fence is only as strong as the two things holding it up: the posts that anchor it in the ground, and the rails that span between them. Everything else—boards, panels, wire, vinyl covering—hangs from those two elements. Understanding what posts and rails are, how they work under load, and why certain decisions made at the time of installation determine whether your fence lasts 5 years or 25 years is the foundation for every other decision in this handbook.
What Posts and Rails Actually Do
Posts are vertical members driven or set into the ground to anchor the fence structure and resist the horizontal and vertical forces acting on it. Rails are horizontal members that span between posts, carrying the weight of infill material (boards, panels, wire, or decorative elements) and transferring that load back to the posts.
A 6-foot fence panel with solid boards presents continuous wind load. That load is concentrated on the rails. The rails transfer it to the posts. The posts transfer it down into the ground through a combination of mechanical anchoring (depth and diameter) and resistance from surrounding soil. If any of those three points fails, the entire system fails.
Consider a straightforward residential example: a 150-foot property-line fence, 5 feet tall, made of pressure-treated 4x4 posts spaced 6 feet apart with 2x4 rails. The posts run 3 feet into the ground and 5 feet above it. Under normal wind conditions, each post absorbs roughly 300 to