How to Close a Gap Under a Fence (4 Ways to Keep Pets & Pests Out)

TL;DR: Gaps under fences form from erosion, settling, or uneven ground. A 3-inch opening is enough for small dogs, rabbits, and rodents. Four fixes work: pouring a concrete mow strip, burying wire mesh, filling with gravel and pavers, or installing a pressure-treated kick board. Choose based on your soil type, whether you rent equipment, and how much digging you're willing to do.

_Last reviewed: July 2026 · 6 min read_

Your fence looks solid from a distance, but the gap underneath tells a different story. Dogs squeeze out, rabbits slip in, and every rain washes more dirt away. Closing that gap is a one-weekend project if you pick the right method for your yard.

Okoniq Property Hub logs each fence repair with photos and cost, so you know when the next section needs attention.

What causes a gap to form under a fence?

Water erosion is the most common reason. Rain washes topsoil downhill, particularly along a fence line where runoff concentrates. Clay soil shrinks when dry and expands when wet, creating a cycle that pulls dirt away from the posts. Settling happens over the first two years after installation as backfill compacts. Slopes amplify all three causes—a 5-degree grade doubles erosion speed compared to flat ground.

Burrowing animals accelerate the process. Groundhogs, rabbits, and armadillos dig under fences to create dens or shortcuts. A single groundhog can move 700 pounds of soil excavating a burrow system. Once a gap exists, smaller pests follow the path.

Poor grading at installation leaves gaps from day one. If the contractor didn't follow the contour or left high spots between posts, you inherit the problem. A proper landscape maintenance plan includes checking fence lines twice a year—once in spring after frost heave, once after fall rains.

How deep should I bury a barrier to stop digging?

Twelve inches is the standard depth to deter most diggers. Rabbits rarely go past 6 inches, but groundhogs and dogs will dig 18 inches if motivated. Wire mesh or hardware cloth buried to 12 inches and bent outward in an L-shape forces animals to give up—they dig down, hit the barrier, and stop.

For chain-link or wood fences, unroll 2-foot-wide hardware cloth (½-inch grid) along the base. Dig a trench 12 inches deep, push the cloth down vertically for 12 inches, then bend the bottom 12 inches out at a 90-degree angle so it lies flat in the trench. Backfill with soil, tamp it, and replant grass or mulch over the horizontal section. The L-shape stops diggers without requiring deeper excavation.

Concrete offers permanence but no flexibility. A 4-inch-deep, 6-inch-wide concrete mow strip poured along the fence line closes gaps on flat or gently sloped ground. Mix one 80-pound bag of concrete per 4 linear feet, pour into a shallow trench, and smooth it flush with grade. This works best where mowing right up to the fence matters—the mower wheel rides the strip, eliminating trimming.

What's the fastest no-dig fix for a small gap?

A pressure-treated 2×6 or 2×4 kick board screwed to the bottom of the fence covers gaps up to 5 inches without excavation. Measure the gap height at the widest point, buy lumber in 8-foot or 16-foot lengths, and cut to fit between posts. Pre-drill holes every 16 inches to prevent splitting, then drive 3-inch exterior screws through the board into the fence's bottom rail or pickets.

Kick boards work on wood and vinyl fences. For chain-link, use treated 1×6 boards wired to the bottom rail with 16-gauge galvanized wire every 12 inches. The board sits on the ground and moves with minor settling—check it each spring and adjust if the gap reappears.

This method fails on slopes steeper than 10 degrees. The board bridges high spots and leaves gaps at low points. On uneven ground, combine a kick board on level sections with spot-fills of gravel or buried mesh where the terrain dips.

Gravel and pavers fill irregular gaps without tools. Dig out loose soil to a depth of 4 inches along the fence line, lay landscape fabric to suppress weeds, then fill with ¾-inch crushed rock. Top with flat pavers or flagstone flush with grade. This drains well, stops casual digging, and adjusts easily if the gap shifts. Replenish gravel every 2-3 years as it settles. Track material purchases and labor hours in Okoniq's maintenance log to budget for the next section.

Will fixing the gap damage existing plants or sprinklers?

Check for irrigation lines before digging. Most sprinkler laterals run 8-12 inches deep—exactly where you'll trench for buried mesh. Mark heads with flags, then dig a test hole every 10 feet to confirm depth. If you hit a line, adjust your trench 6 inches away from the fence and use a shallower 8-inch depth with a tighter mesh grid (¼-inch hardware cloth instead of ½-inch).

Tree roots complicate trenching within the drip line. Roots extend 1.5 times the canopy width; cutting roots thicker than 2 inches stresses the tree. If a mature tree sits within 10 feet of the fence, choose a kick board or gravel fill instead of excavation. For roots under 1 inch, cut cleanly with pruners rather than tearing them with a shovel.

Perennials and shrubs replant easily. Dig them out with a root ball, set them aside in shade with damp burlap over the roots, finish the barrier, then replant immediately. Water daily for a week. Most survive if out of the ground under four hours. Document plant relocations and any irrigation repairs in your property log—future buyers or tenants appreciate knowing what's been moved.

When should I hire a contractor instead of doing it myself?

Hire a fencing pro if the gap exceeds 8 inches or runs more than 50 linear feet. A skid-steer with a trencher attachment cuts a 12-inch trench in minutes; hand-digging that length takes a weekend and risks repetitive strain. Contractors charge $8-15 per linear foot for buried mesh installation, including materials—reasonable if your time costs more than $30/hour.

Rocky or clay-heavy soil warrants professional help. If a spade bounces off hardpan after 4 inches, rent a walk-behind trencher ($90/day) or call a contractor. Clay requires a pickaxe and takes three times longer than loam; trenchers powered by 13-hp engines chew through it.

Sloped yards need grading analysis. If the fence line drops more than 12 inches over 20 feet, a stepped trench or terraced kick boards prevent runoff from undermining your fix. A landscape contractor can tie the repair into existing drainage so you're not back under the fence in two years. For complex drainage problems that affect multiple property features, a comprehensive waterproofing plan addresses the root cause.

FAQ

How much does it cost to close a fence gap?

DIY materials run $2-6 per linear foot: $40 for a 50-foot roll of hardware cloth, $3/bag for concrete, $15 for an 8-foot kick board. Contractor installs cost $8-15 per foot including labor. A 100-foot fence line averages $200-400 DIY, $800-1,500 installed.

Can I use chicken wire instead of hardware cloth?

Chicken wire (1-inch hex mesh) stops chickens but not determined diggers. Groundhogs and large dogs tear through it. Hardware cloth (½-inch square grid, 23-gauge) is stiff enough to resist chewing and digging. Spend the extra $10 per roll for hardware cloth on any gap you want to last five years.

How long does a buried mesh barrier last?

Galvanized hardware cloth lasts 10-15 years in moderate soil. Acidic or salty soil (near coasts or where road salt runs off) cuts life to 7-10 years. Stainless steel mesh lasts 20+ years but costs triple. Inspect annually by digging a test hole at one end—if rust flakes off easily, budget for replacement in the next two years.

Will a kick board rot if it sits on wet ground?

Pressure-treated lumber rated for ground contact (UC4A) resists rot for 15-20 years in damp soil. Use PT pine or cedar, never standard framing lumber. Elevate the board ½ inch on gravel if drainage is poor—drill weep holes every 24 inches to let water escape. Check for soft spots each spring; replace when a screwdriver pushes through easily.

Do I need a permit to add a fence barrier?

Most cities don't require permits for repairs that don't change fence height or location. Adding a kick board or burying mesh falls under maintenance. If you're pouring a concrete mow strip wider than 12 inches or deeper than 6 inches, check local codes—some municipalities regulate impervious surfaces and stormwater runoff. Call your building department if unsure; inspectors prefer a question to an expensive tear-out order.

This is educational information, not construction or legal advice. If your fence sits on or near a property line, confirm boundaries with a survey before making permanent changes. Consult a licensed contractor for structural concerns or complex grading.