A simple picket fence is one of the most rewarding weekend DIY projects a homeowner can tackle. With the right materials, a bit of planning, and some basic tools, you can have a tidy garden border fence up in a day or two. Here's how to do it properly in a New Zealand context.
Do You Need a Building Consent?
For most low garden border fences, you won't need a building consent — but it depends on the height and location. Under Schedule 1 of the Building Act 2004, fences up to 1.5 metres high are generally exempt from consent, provided they don't sit on or near a boundary with a public road or have other specific conditions. However, rules vary between councils, so always check with your local council before you start. You can find general guidance at MBIE Building Performance.
Also check your district plan for any rules about boundary setbacks or fence heights in your area.
Plan Your Fence Layout
Before buying anything, walk the line of your intended fence and consider:
- Total length — measure carefully and add 10% for waste.
- Post spacing — standard spacing is 1.8 metres between posts (centre to centre), which suits most picket styles.
- Gate locations — decide now if you want a gate; it affects post placement and requires heavier posts.
- Underground services — call Before U Dig (0800 248 344) or visit their website to check for buried pipes or cables before you dig.
Choosing Your Materials
For a classic NZ garden picket fence, you'll typically use:
| Component | Common Material | Notes |
|---|---|---|
| Posts | 100×100 mm H5 treated pine | H5 for in-ground contact |
| Rails | 75×50 mm H3.2 treated pine | Two rails per bay |
| Pickets | 75×19 mm H3.2 treated pine | Pre-cut pickets save time |
| Fixings | Galvanised or stainless nails/screws | Avoid plain steel — it rusts |
| Concrete | Rapid-set post mix | One bag per post, typically |
Timber treatment ratings matter in NZ. H5 timber is required for any timber in direct ground contact. H3.2 is suitable for above-ground exterior use exposed to weather. Using the wrong grade will lead to premature rot. You can source treated timber from Bunnings, Mitre 10, or PlaceMakers.
Setting Your Posts
This is the most critical step — a fence is only as good as its posts.
- Mark post positions with stakes and string line.
- Dig post holes at least 450–600 mm deep for a low garden fence (deeper for taller fences or soft ground). A manual post-hole borer or hired power auger makes this much easier.
- Check for plumb using a spirit level on two faces of the post.
- Pour rapid-set concrete around the post, sloping the top of the concrete slightly away from the post to shed water.
- Brace the post and leave it to cure — typically 30–60 minutes for rapid-set, but leave it overnight before loading it.
Post Height Tip
Set posts slightly taller than needed, then cut them to a consistent height with a handsaw or circular saw once all posts are set. Use a string line or laser level to mark the cut line.
Fixing the Rails
Once posts are set and cured:
- Fix two horizontal rails per bay — one near the top and one near the bottom of where your pickets will sit.
- Use galvanised joist hangers or face-fix the rails directly to the posts with 75 mm galvanised screws.
- Keep rails level using a string line or spirit level.
Attaching the Pickets
- Space pickets evenly — a 10–15 mm gap between pickets is typical for a garden border fence.
- Cut a simple spacer block from offcut timber to keep gaps consistent as you work along the fence.
- Fix each picket with two galvanised nails or screws per rail — pre-drilling near the ends prevents splitting.
- Keep picket tops consistent in height using a string line or a purpose-cut height gauge.
Finishing and Painting
A good finish protects your timber and makes the fence look great. Prime and paint or stain all timber, including cut ends, before or immediately after installation.
- Resene and Dulux both offer exterior timber paints and stains well suited to NZ conditions.
- Wattyl also has a solid range of exterior wood coatings.
- Pay special attention to end grain — it absorbs moisture fastest and is where rot typically starts.
- Plan to repaint or re-stain every 3–5 years depending on your exposure and product used.
When to Call a Professional
While a garden picket fence is well within most homeowners' abilities, consider calling a qualified fencer if:
- Your ground is very rocky, sloped, or unstable.
- You need a longer run of fencing or a more complex design.
- You're unsure about boundary locations (a surveyor may be needed).
- The fence is near a pool — pool fencing is subject to strict NZ Building Code requirements and must comply with NZS 8500 and the pool fencing requirements under the Building Act — check with your council for current requirements. This is not a standard DIY job.
You can find experienced, local fencing professionals on tradedirectory.co.nz.
