Whether you're a seasoned contractor or just starting out, choosing the right timber and materials is key to building strong, long-lasting agricultural fencing. From understanding timber treatments like UC4 to selecting the best wire for sheep or cattle, this guide covers the essentials. Read on for practical tips, product insights, and best practices to help you plan and install fencing that stands the test of time.
🌲 Timber Components (Posts, Strainers & Gate Posts)
1. Types of Timber Posts
- Intermediate Posts: Typically 3"–4" diameter, spaced at 2–3m intervals.
- Strainers (End/Corner Posts): Usually 6"–8" diameter, set at 1.2m–1.8m deep, braced with struts or stays.
- Gate Posts: Larger diameter (8"–10"), ideal for load-bearing where gates are hung.
🌳 Timber Treatment Types
1. Green Treated Timber
- Often refers to pressure-treated timber using Tanalith-E or similar copper-based preservatives.
- The “green” colour is simply from the treatment dye.
- Note: Not all green-treated timber is rated for ground contact or long-term durability.
2. UC4 (Use Class 4) Treated Timber
- Specifically treated for ground contact and high moisture exposure.
- Designed to last 15–20 years or more.
- Often kiln-dried before treatment for deeper penetration of preservative.
✅ Best practice: Always use UC4 treated timber for posts in ground contact (strain posts, intermediates, gate posts). Ask suppliers for certification.
🧱 Installing Timber Fencing
A. Post Installation Tips
- Use a post driver (petrol/diesel or tractor-mounted) for efficient installation.
- Ensure strainers are driven or set in concrete to at least 1.2m deep.
- Brace end and corner posts with struts at 45° angle, notched and bolted.
B. Straining Wire
- Start at the end post, tension using wire strainers.
- Terminate wire using a gripple, knot, or a crimp sleeve (depending on wire type).
🐑 Stock Fencing – Wire Types & Grades
1. Most Common Grades of Stock Fencing
| Code | Mesh Size | Height | Common Use |
|---|---|---|---|
| HT8/80/15 | 8 lines, 15cm vertical spacing | 80cm | Sheep |
| HT13/190/15 | 13 lines, 15cm vertical spacing | 1.9m | Deer |
| HT10/120/15 | 10 lines, 15cm vertical spacing | 1.2m | Cattle / Sheep (Mixed) |
| C8/80/15 | Same as HT8/80/15 (Mild Steel) | 80cm | Easier to work with, less tension needed |
2. High Tensile vs Mild Steel
| Feature | High Tensile (HT) | Mild Steel |
|---|---|---|
| Strength | Higher tensile strength | Lower strength |
| Weight | Thinner, lighter | Thicker, heavier |
| Tensioning | Requires proper straining tools | Can be tensioned by hand or simpler tools |
| Sag over time | Holds tension longer | Sags more over time |
| Ease of use | Less forgiving, harder to knot | Easier to tie and work |
| Cost | Slightly higher upfront | Slightly cheaper |
| Longevity | Lasts longer (better coating) | Shorter lifespan if not well galvanised |
🔧 Pro tip: Use HT wire with gripples or crimps for fast installation. Avoid tying knots unless experienced.
✅ Recommended Setup for Agricultural Stock Fencing
- Strainer Posts: 8" UC4 treated, driven or concreted at least 1.2m deep
- Intermediate Posts: 3.5–4" UC4 treated, spaced 2.5–3m
- Wire: HT8/80/15 for sheep; HT10/120/15 for mixed grazing
- Stays/Bracing: 3"–4" round timber, 2.4m long, properly notched
📋 Final Tips for Contractors
- Always confirm timber is UC4 when quoting or sourcing.
- Ensure wire is hot-dip galvanised to BS EN 10244-2 Class A for long service life.
- Keep gate post spacing wider than needed – allows for future upgrades.
- Use stock-proof gates with proper hanging and slam posts.
