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A 13 cm × 13 cm hole is the recognised UK “hedgehog highway” size. It lets hedgehogs move between gardens for food and shelter, while being too small for dogs and foxes and generally too tight for adult cats. Security stays high when the gap is localised, metal‑edged and kept at ground level.
Place a single, controlled opening and reinforce the edges so the fence still resists wind, pets and wear. On Essex clay, keep the bottom edge flush with finished ground but above standing water. Add a small pea‑shingle pad either side for drainage.
Start with a long‑life structure. We favour concrete slotted posts for longevity and easy panel swaps. Compare options in concrete slotted posts vs timber, or browse our concrete slotted posts. Closeboard panels are stiffer and handle Essex winds better than waney edge—see our closeboard panels.
Use concrete gravelboards along most bays for rot protection and weight. Fit one bay with a UC4 timber gravelboard for the wildlife gap—this keeps durability across the run while allowing a clean, accurate cut‑out. Browse concrete gravelboards for the main line. In exposed or coastal areas, heavier closeboard with concrete posts performs best.
Mark likely routes: quiet corners, under hedges and beside gateposts. One 13 cm gap per boundary side is usually enough. Keep the opening flush to ground, add a 300 mm square shingle pad each side, and avoid boggy spots.
Agree locations with neighbours before cutting a shared fence. Gaps do not affect height rules, but posts and panels must still comply. Check the 2 m fence height regulations in the UK and locate services first with before you dig.
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Fit a UC4‑treated timber gravelboard in the chosen bay. Mark a 130 mm square at least 50 mm from ends and fixings. Drill the four corners, jigsaw the opening with a fine wood blade, and smooth the cut. Treat all exposed timber with end‑grain preservative (see UC3 vs UC4).
Reinforce the edges with 25–30 mm galvanised angle or U‑trim, screwed into sound timber at 150–200 mm centres. This resists chewing and keeps stiffness. Finish with a pea‑shingle pad inside and out so silt and leaves do not block the hole. The gap stays neat, drainable and strong.
Do not cut concrete gravelboards; they can crack and spall. Instead, run concrete posts and concrete gravelboards across the fence, but designate one bay with a UC4 timber gravelboard for the hedgehog hole.
Cut and reinforce the 13 cm opening as in Method A. This gives long service life across the run, while the gap bay remains simple to maintain or replace within a slotted system.
For chain link or welded mesh, cut a 130 mm square at ground level on a natural route. Hem each cut edge tightly around a 6 mm galvanised rod or angle to stop fraying. Bind with galvanised tie wire at 100 mm centres for a rigid frame.
Tie the reinforced edges back to line wires and the nearest post to spread load. Peg or bury the mesh base neatly so the only opening is the hedgehog gap. Add pea shingle for drainage and to keep soil from clogging the hole.
Fix a 600–900 mm rabbit or stock‑wire skirt along the base to harden the lower fence line. For dogs that dig, add a 300 mm buried section or an L‑shaped apron pegged under turf. Keep the 13 cm opening clear and reinforced.
Remove footholds near the gap. If cats climb, add a light trellis topper to increase height without much weight. The aim is one controlled, hedgehog‑sized opening and no other weaknesses pets can exploit.
This image was generated with AI and may not always represent the product or service exactly.
Place the 13 cm opening tight to a gatepost, not under the gate leaf. Fit a drop seal or a timber fillet under the gate to remove under‑gate gaps and keep the wildlife hole localised.
On paving or near services, use bolt‑down post supports to avoid digging and create a tidy, framed opening next to the post. Keep sightlines low around the hole so pets pay less attention to it.
Set the opening flush to final ground level, but lift it clear of standing water. Bed a 300 mm × 300 mm pea‑shingle pad on both sides. It drains quickly and stops silt washing into the hole.
Essex shrink–swell clays need deeper posts and firm backfill. Do not undermine post footings while shaping the gap. Mark pipes and cables before you dig, and keep any French drain or soakaway stones stable around the bay.
Essentials:
Checklist:
Choose long‑life structure first: concrete slotted posts, concrete gravelboards for most bays, and one UC4 timber gravelboard for the gap bay. Pair with closeboard panels or feather edge on cant rails for stiffness in Essex winds.
For pet control, add a rabbit or stock‑wire skirt, line wire or chain link where needed. Finish with quality ironmongery and reliable post mix. Essex Concrete and Fencing stocks durable, practical components that suit local weather and clay soils.
No. A 13 cm square is too small for dogs and generally too tight for adult cats. It is sized for hedgehogs and similar wildlife.
No. Cutting concrete gravelboards can crack and weaken them. Use a UC4 timber gravelboard in one bay and cut the 13 cm hole there.
Yes, if the fence is shared or theirs. Agree location and details first to avoid disputes and keep boundaries tidy.
Set the hole flush to finished level and add a pea‑shingle pad both sides. On clay soils, keep the gap away from puddles and improve local drainage.
Small rodents can use smaller gaps than 13 cm. Control entry elsewhere with skirts, tidy bases and sealed under‑gate gaps while keeping the hedgehog hole open.
Make a 130 mm square cardboard template. Test the position at ground level, confirm clearance and drainage, then mark and cut accurately.
Place the gap where ground meets the gravelboard evenly and still drains. Add shingle to manage run‑off and keep the opening clear.
