A post-and-rail fence is one of the most practical and cost-effective ways to mark a paddock boundary in New Zealand. With the right materials, basic tools, and a bit of preparation, most capable DIYers can tackle this project over a weekend or two. Here's how to do it properly.
Plan Before You Dig
Before you buy a single post, take time to plan your fence line. Walk the boundary and note any changes in slope, wet ground, rocky areas, or existing trees. Measure the total length accurately — this determines how many posts and rails you'll need.
Key planning considerations:
- Confirm the boundary with your title plan or survey pegs. Building on a neighbour's land is a costly mistake.
- Check with your local council whether a building consent is required. Most rural paddock fences fall under Schedule 1 exemptions of the NZ Building Code, but rules vary by district — always confirm before starting.
- Consider what livestock the fence needs to contain. Cattle require heavier, more robust construction than sheep or horses.
- Contact MBIE Building Performance if you're unsure about consent requirements for rural fencing.
Choose the Right Materials
Timber
For NZ conditions, H4 treated pine is the standard choice for posts going into the ground — it's rated for ground contact and resists rot and borer. Rails are typically H3.2 treated pine, suitable for above-ground exterior use exposed to the weather.
Rough-sawn timber is perfectly adequate for a paddock fence and is usually more economical than dressed timber. Common rail sizes are 100 × 50 mm or 150 × 50 mm. Posts are typically 100 × 100 mm or 125 × 125 mm.
You can source treated timber from Mitre 10, Bunnings, or PlaceMakers. For large quantities, a local timber merchant or rural supplier may offer better pricing.
Post Spacing and Depth
Standard post spacing for a paddock fence is 2.4 m to 3.0 m between posts. Closer spacing gives a stronger fence; wider spacing reduces cost but may allow rails to flex or sag over time.
As a general rule, bury at least one-third of the post length in the ground. For a fence with 1.2 m above ground, you'd use a 1.8 m post with 600 mm in the ground. On soft or wet ground, go deeper.
Corner and strainer posts must be set deeper and braced — these take the most tension and are critical to the fence's integrity.
Tools You'll Need
- Tape measure, string line, and pegs for setting out
- Post-hole borer (manual or tractor-mounted — hire one for larger jobs)
- Sledgehammer or post driver
- Level
- Circular saw or handsaw
- Drill and appropriate bits
- Galvanised nails or coach screws
- Tamping bar and gravel or concrete for setting posts
Step-by-Step: Building the Fence
1. Set Out the Fence Line
Run a string line between your corner pegs to mark the fence line. Use a tape measure to mark post positions at your chosen spacing. Spray paint or a stake at each position makes drilling easier.
2. Install Corner and Strainer Posts First
Corner posts and end posts (strainer posts) anchor the whole fence. Set these in concrete for maximum strength — a bag of rapid-set concrete per post is typical. Brace corner posts with a diagonal timber brace or a horizontal brace-and-wire assembly back to a second post. Allow concrete to cure fully (at least 24 hours) before tensioning any wire or attaching rails.
3. Bore and Set Line Posts
Bore holes for your line posts. Set them in compacted gravel (for free-draining ground) or concrete, checking each post is plumb with a level. Tamp firmly in layers as you backfill.
4. Attach the Rails
Once all posts are set and firm, attach your rails. A standard paddock fence has 2 to 4 rails depending on the livestock. Nail or screw rails to the stock side of the posts — this means animals pushing against the fence push the rails into the posts rather than off them.
Use galvanised nails or screws to prevent rust staining and corrosion. Two fixings per rail end is the minimum; three is better on the bottom rail.
5. Check and Finish
Walk the completed fence line, checking for any loose rails, out-of-plumb posts, or low spots where stock could push through. Trim any post tops at an angle to shed water and extend the life of the timber.
Tips for a Long-Lasting Fence
- Never use untreated timber in ground contact — it will rot within a few years in NZ's climate.
- Keep the base of posts clear of built-up soil or mulch, which traps moisture.
- Inspect the fence annually and replace any split or rotting rails promptly.
- BRANZ has useful guidance on timber durability and treatment classes for NZ conditions.
When to Call a Professional
Most homeowners can build a straightforward post-and-rail paddock fence, but consider hiring a qualified fencer if:
- The terrain is steep, rocky, or very wet and requires specialist equipment.
- You need a high-tensile wire fence in addition to rails (tensioning wire correctly requires experience and the right tools).
- The fence is on or near a legal boundary and you want to avoid disputes.
- You need a large project completed quickly and to a consistent standard.
A professional fencer will also know local ground conditions and can advise on the best post-setting method for your soil type. You can find qualified local fencers on tradedirectory.co.nz.
Safety note: Always call Before U Dig (0800 248 344) before any digging to check for underground services. Striking a buried cable or pipe is dangerous and costly.
