Materials & specs
Module 5: Post Selection & Specifications
Posts fall into two structural categories that are frequently confused: line posts, which just hold wire or rail off the ground between anchor points, and corner/brace posts, which carry the full tension load of the fence run and must be engineered accordingly. Undersizing a corner post is the single most common cause of a sagging, ineffective fence line.
| Post type | Typical diameter/gauge | Role |
|---|---|---|
| Wood line post | 4–5 in top diameter | Support only, spaced along the run |
| Wood corner/brace post | 6–8 in diameter, set 3–4 ft deep | Carries tension, braced with a horizontal kicker post |
| T-post (steel) | 5–6 ft, studded | Line post only — never a corner post, and always capped for horses |
| Fiberglass rod | 5–7 ft | Lightweight line post, common with electric tape |
| Composite/vinyl | Manufacturer spec | Line or corner, load-rated by product |
Setting depth is generally one-third of the post's total length for line posts in stable soil, and deeper with concrete footing for corner posts carrying tension. Pressure-treated wood rated for ground contact is the default for any post set directly in soil; untreated wood will rot at the soil line within a few seasons.
An uncapped steel T-post is a well-documented cause of severe puncture and eye injuries in horses. Every exposed T-post top on a horse property should carry a manufactured safety cap — no exceptions, including in "temporary" cross-fencing.