Post-and-Rail Fence Design: Spacing, Dimensions, and Construction

A post-and-rail (or post-and-board) fence uses horizontal rails between posts. For a 4-foot height:

Typical Specs

• Rails: Two rails—bottom 4" above grade, top 4" below picket tops.
• Pickets/Boards: 2–4" wide, ¾" thick. Space at ½ to 1× board width (1–4" gaps).
• Posts: 4×4 or 6×6, set 30–36" deep in concrete.

Horse/Split-Rail Variation

• Height: 54" (3 rails).
• Gap at bottom ≥8" (hoof safety).
• Pre-mortised posts simplify assembly.

Critical Checks

• Verify property lines with a survey.
• Check local zoning for height, setback, style restrictions.
• Call 811 before digging.

Use galvanized or stainless hardware for longevity.