How to Build a Garden Fence: Step-by-Step DIY Guide

Building a garden fence is one of the most practical DIY projects you can tackle. It’s not complicated — if you can dig a hole, use a spirit level, and drive a screw, you can build a fence. The key is getting the posts right. Once the posts are plumb and solid, the rest is almost easy.

This guide covers the full process for a standard panel fence (the most common type in UK gardens), but the principles apply equally to closeboard, hit-and-miss, and picket fences. I’ll cover both concrete and post spike methods so you can choose what suits your situation.

Planning and Legal Considerations

Boundary Rules and Neighbour Communication

Before you buy a single post, sort these out:

• Check whose boundary it is. Your property deeds (or Land Registry plan) will show which boundaries you’re responsible for. The common belief that “your fence is the one on the left” is a myth — there’s no standard rule.
• Talk to your neighbour. Even if the fence is entirely on your land, letting your neighbour know is basic courtesy and avoids disputes. If it’s a shared boundary, discuss the style, height, and cost-sharing.
• Planning permission: In most cases, you do not need planning permission for a garden fence up to 2 metres tall (1 metre if it fronts a highway). There are exceptions for listed buildings, conservation areas, and some new-build estates with restrictive covenants. Check your local council’s website if you’re unsure.
• Utilities: Before digging post holes, check for buried cables and pipes. Call your utility providers or use a cable avoidance tool (CAT scanner) if you’re unsure. Hitting a gas main or electric cable is no joke.

Choosing Fence Style and Height

For most back gardens, a standard 1.8m (6ft) lap panel or closeboard fence is the go-to choice. Lap panels are the cheapest and easiest for a first project. Closeboard fences are sturdier and look better, but involve more individual boards and rails.

If you’re in an exposed location that gets hammered by wind, consider hit-and-miss fencing. Solid panel fences act like sails — they catch the wind and get blown over. Hit-and-miss boards let wind pass through while still providing good privacy.

Tools and Materials

Tools you’ll need:

• Post hole digger or spade (for concrete method)
• Post spike driver or sledgehammer (for spike method)
• Spirit level (1200mm)
• Tape measure
• String line
• Cordless drill/driver
• Panel saw or circular saw (for trimming)
• Mixing bucket or wheelbarrow (for concrete)

Materials for a 6-panel fence run (roughly 11 metres):

On timber treatment: Always buy pressure-treated (tanalised) posts and panels. Untreated timber rots within a few years in ground contact. Even with treated timber, applying an additional coat of fence treatment or wood preserver extends the life further.

Step 1 — Mark Out the Post Positions

1. Run a string line along the full length of the fence run, pulled taut between two stakes. This is your fence line — every post must touch this string.
2. Mark the first post position. Start at one end (usually against the house wall or an existing structure).
3. Measure and mark each subsequent post position. Standard fence panels are 1.83m (6ft) wide, so posts should be 1.83m apart centre to centre. Use a tape measure and spray paint or a wooden stake to mark each position.
4. Double-check the total length. Measure the full run and confirm that your post positions add up. Adjust spacing slightly if needed — it’s better to have slightly uneven spacing than to end up 100mm short at the far end.

Pro tip: Lay the fence panels out on the ground along the fence line before you dig. This lets you visualise the layout and catch any measurement errors before you’ve committed to concrete.

Step 2 — Dig Post Holes (or Use Post Spikes)

Concrete vs Post Spikes — Which Is Better?

My recommendation: For a standard 1.8m panel fence in normal soil, post spikes are excellent and dramatically easier. For exposed positions, heavy clay soil, or fences over 1.8m tall, go with concrete for the extra strength.

Digging post holes (concrete method):

1. Dig each hole about 300mm × 300mm and 600mm deep (a third of the post length should be underground).
2. Add 50-75mm of gravel at the bottom for drainage.
3. Place the post in the hole, check it’s plumb with a spirit level (on two adjacent faces), and brace it temporarily.
4. Pour in Postcrete (a fast-setting post mix — just add water and it sets in 5-10 minutes) or mix concrete to a thick consistency and pack it around the post.
5. Slope the concrete slightly away from the post at the top so water drains away rather than pooling.

Using post spikes:

1. Place the spike on the marked position.
2. Insert a driving tool (a short piece of fence post or a purpose-made driving plug) into the top of the spike socket.
3. Drive the spike in with a sledgehammer, checking plumb regularly. If it starts going off-vertical, lever it back with a long bar.
4. Drive until the socket sits at ground level.
5. Slide the post into the socket and tighten the bolts.

Step 3 — Set the Posts Plumb and Level

This is the critical step. If your posts aren’t plumb (vertical) and in line, the fence will look terrible — and you’ll struggle to fit the panels.

• Check plumb on two faces — front-to-back and side-to-side. A post that looks plumb from one direction can be leaning from another.
• Check the string line — every post should just touch the string. If a post is pushing the string out, it’s not in line.
• Check the height — all posts should be the same height (or follow a consistent slope on sloping ground). Run a spirit level across from one post to the next.
• Brace posts temporarily with diagonal timbers screwed to the post and staked into the ground while concrete sets.

Don’t rush this step. Adjusting a post that’s 10mm out now is trivial. Adjusting one that’s set in concrete and has panels attached is a nightmare.

Step 4 — Attach Rails or Panels

Once all posts are set and the concrete has cured (24 hours minimum, 48 if it’s cold), you can attach the panels.

For panel fences:

1. If using gravel boards — fix these first, between the posts at ground level. They protect the bottom of the panel from ground contact and damp. Use galvanised screws or gravel board clips.
2. Lift the panel into position between two posts, resting on the gravel board (or on temporary spacers if no gravel board).
3. Fix using panel clips or U-brackets — these nail or screw to the post and grip the panel frame. Use at least three per side (top, middle, bottom).
4. Alternatively, screw directly through the panel frame into the post — use 75mm galvanised screws, pre-drilling to avoid splitting. This is stronger than clips but less adjustable.
5. Check the panel is level before final fixing.

For closeboard fences: Fix the arris rails (triangular cross-section rails) between the posts first — typically two for a 1.2m fence, three for 1.8m. Then nail or screw the featherboards to the rails, overlapping each board by about 10-15mm.

Step 5 — Trim and Finish

1. Fit post caps to the top of each post. These shed water and dramatically reduce post-top rot, which is the most common failure point. Even a simple flat cap helps; shaped caps look better.
2. Trim any posts that are too tall. Mark the height, use a circular saw or handsaw, and cut level. Angle the cut very slightly so water runs off.
3. Apply fence treatment or paint. Even pressure-treated timber benefits from a coat of fence treatment. It protects against UV fading and adds water resistance. Choose a colour you like — the range of wood stains and treatments available now is enormous.

Treating and Protecting Your Fence

A new fence left untreated will turn grey within a year and start deteriorating within 3-5 years. Treated properly, it’ll last 15-20 years.

Treatment options:

• Fence oil/treatment — penetrates the wood and protects from within. Needs reapplying every 2-3 years. Low sheen, natural look.
• Fence paint — sits on the surface. Gives a solid colour and good protection but can peel if the wood is damp. Needs recoating every 3-5 years.
• Creosote alternatives — traditional creosote is now restricted, but alternatives give a similar look and protection.

Apply treatment to a dry fence. If you’ve just built it and the timber is fresh from the yard, it may be too wet. Wait for a dry spell (a week or two) before treating.

Fence Post That Won’t Stay Straight? Here’s the Fix

If a post starts leaning after installation (especially common with post spikes in soft soil), you have several options:

• Drive a fence post support stake — a galvanised steel angle bracket that you hammer into the ground beside the leaning post and bolt to it. Quick and effective for moderate lean.
• Add a concrete collar — dig around the base of the spike/post and pour a concrete collar. This adds lateral stability.
• Replace the spike with concrete — if the spike won’t hold in your soil, pull it out, dig a proper hole, and concrete the post in.
• Add a diagonal brace — for end posts that take the most strain, a diagonal brace back to a ground anchor can prevent leaning.

Recommended Fencing Tools and Materials

For a typical 6-panel fence run, here’s your shopping list:

• Post hole digger — saves enormous effort over a spade, especially in clay soil.
• Spirit level (1200mm) — essential for plumb and level checks.
• Postcrete or post spikes — your choice depending on soil and preference.
• Panel clips (galvanised) — easier and more forgiving than screwing directly through panels.
• Post caps — simple but effective at preventing post-top rot.
• Gravel boards — protect panels from ground contact. Well worth the small extra cost.
• Fence treatment — apply within the first few months for best results.

Total cost for a 6-panel fence run: roughly £250-400 depending on panel quality and whether you choose concrete or spikes. That’s about half what a fencing contractor would charge for the same job — and you’ll have the tools for the next fence project too.