How to Build a Garden Fence – DIY Guide
Building a garden fence involves setting posts in concrete at 1.8 m centres, fixing arris rails between them, and nailing feather-edge boards vertically with a 10 mm overlap. Allow posts to cure for 48 hours before applying rails and boards. A standard 10 m run takes one weekend.
- Post-hole digger or spade
- Spirit level
- Tape measure
- Cordless drill and screwdriver bits
- Claw hammer
- String line and stakes
- Saw
- Safety goggles and gloves
- Timber fence posts (100 × 100 mm, 2.4 m long)
- Arris rails (75 × 75 mm, 1.8 m long)
- Feather-edge fence boards (100 mm wide, 1.2 m or 1.8 m long)
- Gravel boards (150 mm wide)
- Post caps
- Ready-mix concrete (post-fix type)
- Galvanised nails or exterior screws
- Timber preservative treatment
Step-by-Step Guide
Mark out your fence line
Run a string line between two corner pegs to define the fence run, then mark each post position at 1.8 m intervals with a cane. Check the line is straight with a tape measure and confirm the boundary with your neighbour before you dig — the Garden Guide covers boundary rules and good-neighbour practice worth reading before you start.
Dig and set the fence posts
Dig each post hole to a minimum depth of 600 mm — a third of the total post length — using a post-hole digger or spade. Stand the post in the hole, check it is plumb on two faces with a spirit level, then fill around it with post-fix concrete mixed according to the bag instructions. Brace each post while the concrete sets for at least 48 hours before applying any load.
Fit the gravel board and arris rails
Once posts are cured, fix a gravel board along the base of each bay to keep the fence boards clear of the ground and prevent premature rot. Nail or screw arris rails between posts at roughly 300 mm from the top and 300 mm from the bottom of the fence height. If you ever need to fix a leaning fence post, the rail joints are usually the first place to check for failure.
Fix the feather-edge boards
Start at one end post and nail or screw the first feather-edge board vertically, thick edge facing the neighbour’s side, using two fixings per rail. Butt the next board so its thick edge overlaps the thin edge of the previous board by at least 10 mm — this overlap is what weatherproofs the fence. Use a piece of timber offcut as a consistent spacing guide and check vertical alignment with a spirit level every three or four boards. If you need to fix a garden fence panel on an existing run, the same fixing principle applies.
Fit post caps and treat all timber
Nail a post cap to the top of every post to shed rainwater and reduce end-grain absorption, which is where rot starts. Apply a quality timber preservative to all surfaces — boards, rails, posts, and gravel boards — paying particular attention to end-grain cuts. Re-treat the fence every one to two years to maintain protection; this single step will more than double the life of the structure.
Check for level and make final adjustments
Step back and sight along the fence line to check the top of the boards runs level. Use a long straight edge or string line along the top of the boards to identify any that have drifted high or low, and adjust fixings before the timber settles. A clean, level fence line is the mark of a well-built job — take five minutes here to get it right.
Frequently Asked Questions
How deep should fence posts be set in the ground?
As a rule, set posts to a depth of one-third of their total length — so a 2.4 m post needs at least 600 mm in the ground. In soft or sandy soil, go deeper and pack the base with a layer of hardcore before adding concrete to improve stability.
Do I need planning permission to build a garden fence?
In England, you do not generally need planning permission for a fence up to 2 m high alongside a boundary, or 1 m high adjacent to a highway. Check current permitted development rules on the Planning Portal before you start, as restrictions apply in conservation areas and for listed buildings.
What is the best timber for a garden fence in the UK?
Pressure-treated softwood (usually Scots pine or spruce) is the standard choice — it is widely available, cost-effective, and resists rot well when kept treated. Western red cedar is a premium alternative that naturally resists decay without treatment, but costs significantly more.
How do I stop fence posts rotting in the ground?
Use pressure-treated posts rated for ground contact (UC4 treatment class), set them in concrete rather than bare soil, and fit post caps to prevent water pooling on end grain. Inspect the base of each post annually and apply fresh preservative to any exposed wood, especially around the concrete collar where moisture collects.
Can I build a fence without concrete?
Yes — post spikes (also called fence spikes or fence post supports) driven into firm soil are a faster alternative and keep timber above ground level, reducing rot risk. They work well in gardens with solid subsoil but are not suitable for soft, sandy, or waterlogged ground where the fence needs maximum stability. Our guide to fixing a leaning fence post covers when spikes fail and how to remedy it.
Before driving the first nail, brace each post pair with a temporary diagonal batten nailed across the inside face — this locks the posts in position while you work and stops the frame racking as you load it with boards. Remove the bracing once the boards are half-way fixed and the structure is self-supporting.
Sources
- HSE — Safe use of hand tools and manual handling on site — hse.gov.uk
- Planning Portal — Fences, gates and garden walls (permitted development) — planningportal.co.uk
- Which? — How to put up a garden fence — which.co.uk
This guide is for general information only. Always work safely and follow manufacturer instructions. DIYnut accepts no liability for injury or damage arising from DIY work.
