Table of Contents
Wood Fence Material Basics
Building a wood fence requires careful material planning to avoid costly return trips to the lumber yard or running short mid-project. The primary components of a standard wood fence are vertical posts (typically 4x4 pressure-treated lumber), horizontal rails (typically 2x4 lumber), and pickets or fence boards (typically 1x4 or 1x6 lumber). Additional materials include concrete for post footings, galvanized nails or screws, and optional post caps.
Post spacing is one of the most critical decisions in fence construction. Standard post spacing is 6 to 8 feet on center, with 8 feet being the most common for residential privacy fences. Closer spacing (6 feet) provides more rigidity and better wind resistance, while wider spacing (8-10 feet) uses fewer posts but requires stronger rails. For areas with high winds, 6-foot spacing is recommended.
The number of pickets depends on the total fence length, picket width, and desired gap between pickets. Privacy fences have zero gap (or even overlap for board-on-board styles), while decorative fences may have 1-3 inch gaps between pickets. A standard 6-foot privacy fence with 3.5-inch wide pickets requires approximately 2.7 pickets per linear foot of fence, or about 21-22 pickets per 8-foot section.
Material Calculation Formulas
Common Fence Lumber Sizes
| Component | Size | Length | Material | Approx. Cost |
|---|---|---|---|---|
| Post | 4x4 | 8 ft or 10 ft | Pressure-treated pine | $8 - $16 each |
| Rail | 2x4 | 8 ft or 16 ft | Pressure-treated pine | $5 - $10 each |
| Picket | 1x4 | 6 ft | Cedar or PT pine | $2 - $5 each |
| Picket | 1x6 | 6 ft | Cedar or PT pine | $3 - $7 each |
| Concrete | 50 lb bag | N/A | Fast-setting mix | $4 - $6 each |
| Post Cap | 4x4 | N/A | Wood or copper | $2 - $15 each |
Installation Guidelines
- Post depth: Bury posts at least 1/3 of their total length. For a 6-foot fence, use 8-foot posts with 24 inches buried. For an 8-foot fence, use 12-foot posts with 36 inches buried.
- Post hole diameter: Dig holes 10-12 inches in diameter, three times the post width. A post hole digger or power auger makes this work much easier.
- Concrete footings: Fill each hole with 4-6 inches of gravel for drainage, set the post, then pour concrete to within 2-3 inches of ground level. Mound concrete slightly to shed water away from the post.
- Rail installation: Attach rails to the post face (flat side toward pickets) or use rail brackets for a cleaner look. The top rail should be 6-8 inches below the top of the pickets; the bottom rail should be 6-8 inches above ground level.
- Picket attachment: Use two galvanized or stainless steel screws (or ring-shank nails) per picket at each rail location. For a 3-rail fence with 1x4 pickets, that is 6 fasteners per picket.
- Fasteners: Use hot-dipped galvanized or stainless steel fasteners with pressure-treated wood. Standard zinc-plated fasteners will corrode when in contact with treated lumber chemicals.
Frequently Asked Questions
How many pickets do I need for 100 feet of fence?
For a privacy fence with 3.5-inch wide (1x4) pickets and no gap, you need 100 x 12 / 3.5 = approximately 343 pickets. Add 5% waste for cuts and defects: about 360 pickets. For 5.5-inch (1x6) pickets, you need 100 x 12 / 5.5 = approximately 218 pickets, plus waste: about 229 pickets.
How much does a wood fence cost per foot?
A standard 6-foot cedar or pressure-treated privacy fence costs $12-$25 per linear foot for materials only. Professional installation adds $10-$20 per linear foot. A 150-foot fence typically costs $1,800-$3,750 for materials or $3,300-$6,750 installed. Cedar costs more upfront but lasts longer and weathers to an attractive gray patina without chemical treatment.
Should I use 2 or 3 rails?
Three rails are recommended for fences 6 feet or taller. The third rail prevents pickets from bowing and warping, provides additional fastening points, and significantly increases the fence's resistance to wind loads. Two rails are acceptable for fences 4 feet or shorter. Some builders add a third rail even to 4-foot fences for added durability.
What wood species is best for fencing?
Western red cedar is the premium choice for wood fencing, offering natural rot and insect resistance, dimensional stability, and beautiful grain. Pressure-treated southern pine is the most economical option and lasts 15-20 years. White oak and black locust are extremely durable but harder to find and more expensive. Avoid untreated pine, spruce, or fir, which will rot within 3-5 years when exposed to ground contact and weather.