How to Install Timber Close Board Fencing: Posts, Rails, Pales and Gravel Boards

Quick Answer: Close board (also called feather edge) fencing uses overlapping vertical pales fixed to two or three horizontal arris rails between square or "morticed" timber posts, with a horizontal capping board on top and a treated gravel board at the base. Posts are set in concrete to 600mm depth for a 1.8m fence per BS 1722-5. All timber should be pressure-treated to BS 8417 Use Class 4 (in-ground) and Use Class 3 (above-ground). The fence line should not exceed 2m above ground level adjacent to a non-highway boundary, or 1m where adjacent to a highway, before planning permission is required.

Summary

Close board is the workhorse of UK boundary fencing — sturdier than overlap panels, more wind-resistant, and far easier to repair plank-by-plank rather than replacing whole panels. It dominates the residential garden market because it tolerates ground movement, lasts 15–25 years if specified correctly, and gives a solid privacy screen that holds up to dogs, children and prevailing weather.

The single biggest failure mode of close board fencing is the gravel board–post junction. Untreated softwood pales sitting in soil rot in 5–7 years. The cure is good detailing: a pressure-treated gravel board separating pales from ground contact, posts set in concrete with the post foot above the gravel board's bottom edge, and capping board to keep the top of the pales from cupping.

This article covers the installation sequence, timber and fixings specification, and the regulations that apply. The line-level work — alignment, set-out and post setting — is covered in fence post installation depth. Where the close board fence is for a security or noise application, see acoustic fencing noise barriers.

Key Facts

Quick Reference Table

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Fence Height Post Size Post Depth Arris Rails Pale Overlap
0.9m 75 × 75mm 450mm 2 12–25mm
1.2m 100 × 100mm 500mm 2 12–25mm
1.5m 100 × 100mm 600mm 2 or 3 12–25mm
1.8m 100 × 100mm 600mm 3 25mm
2.0m 125 × 125mm 750mm 3 25mm
Timber Type Use Class Application Service Life
Pressure-treated softwood (Tanalith E) UC4 Posts in ground 15+ years
Pressure-treated softwood (Tanalith E) UC3 Above-ground pales, rails 15–25 years
Brown-treated softwood UC2/3 Garden joinery (rarely UC4) 10–15 years
Untreated softwood n/a Not for ground contact 3–5 years
Oak (heart) n/a Posts; no treatment 25–40+ years (heart only)

Detailed Guidance

Setting out the fence line

Before any digging:

  1. Boundary verification — check Land Registry title plan; agree boundary line with both neighbours in writing if possible
  2. Underground services — CAT scan along the fence line; mark gas, water, electric and telecoms
  3. Levels — survey the run; close board can step or rake depending on slope. Steps are easier for the installer; raked rails sit better with the ground
  4. Setting out posts — mark post centres at 1.8m intervals; check string-line for line and level

Digging post holes

For a 1.8m fence with 100mm × 100mm posts:

For 2m+ fences in exposed locations, deepen to 750mm and consider 125mm × 125mm posts.

Setting posts in concrete

Two approaches:

Wet-mix concrete (1:2:4 mix):

Postcrete (rapid-set):

Wet-mix is cheaper and stronger long-term but slower. Postcrete is the practical choice for fencing contractors working to a daily output.

Fitting arris rails

For morticed posts (rails sit into a square mortice cut in the post):

For face-fixed rails (typical with concrete or metal posts), galvanised rail brackets are screwed to the post face.

Fixing pales (feather edge boards)

Sequence:

  1. Fit the gravel board first (treated softwood or concrete), leaving 50mm clearance from the underside of the first pale to ground
  2. Start at one end; nail or screw first pale to all rails with two fixings per rail (one at each edge)
  3. Lap the next pale 25mm over the thick edge of the previous; fix into rails — the fixing also catches the pale below
  4. Continue across the bay
  5. Last pale in each bay: trim to fit, fix
  6. Fit capping rail along the top with weather-drip cut on outside edge

Pales should overlap consistently — a string-line at the bottom edge keeps it tidy. The thinner ("feather") edge faces outward; the thicker edge sits behind the next pale.

Gravel boards and capping

A gravel board separates pales from soil contact. Options:

For mid-spec installs, concrete gravel boards with timber close board above is the long-life combination. Pales can then be replaced individually over 20+ years without disturbing the foundations.

Cap rail with a 75 × 25mm timber capping, fixed with galvanised nails. The capping protects end-grain at the top of each pale from water ingress.

Fixings — get this right or the fence fails

Drainage and ground conditions

In waterlogged or clay-heavy ground:

For severely waterlogged ground, consider concrete posts with timber face — these eliminate post rot entirely. See concrete post gravel boards.

Frequently Asked Questions

How long should close board fencing last?

A correctly specified close board fence — UC4 posts in concrete, UC3 pales and rails, concrete gravel board, capping rail, galvanised fixings — will last 20–25 years. The first failure is usually at the pale-to-gravel-board junction; a concrete gravel board pushes this beyond 25 years.

Can I install close board fencing without planning permission?

Yes, provided the fence does not exceed 2m above natural ground level (1m where adjacent to a highway). On the front boundary of a Listed Building or in a Conservation Area, additional consents may apply. See planning permission fences walls.

Should I dip the post foot in bitumen before setting?

This is traditional but no longer recommended. Modern pressure-treated softwood (UC4) is designed for direct ground contact. Adding bitumen can actually create a moisture barrier that traps water against the wood at the air-concrete interface and accelerates failure.

Which side of the fence has the "good" side?

Trade convention is the "smooth" / capping side faces outwards (i.e. into your neighbour's garden). The rails and post mortices are on the owner's side. Some councils and developers reverse this — there's no statutory rule. Agree it with the neighbour and document the line.

Do I need to notify Building Control for a fence?

No. Fences are not notifiable under Building Regulations. Planning permission applies to height (above 2m or 1m near highway). Listed Building Consent may apply on listed properties.

Regulations & Standards