The most reliable way to keep groundhogs from digging under your shed is to install a buried wire mesh barrier around the perimeter, bent into an L-shape at the bottom so the animal hits a horizontal wall of metal every time it tries to dig down. This method, combined with evicting any groundhogs already living there, solves the problem permanently for most homeowners.
Why Groundhogs Target Sheds
Groundhogs don’t pick your shed at random. A solid roof overhead protects them from predators and weather, making the space beneath a shed or garage prime real estate. Their burrows typically run 15 to 50 feet long with chambers 2 to 6 feet underground, and each burrow system has two to five entrances for quick escape. Once a groundhog establishes a burrow under your shed, the tunnel network can become extensive enough to undermine the foundation or cause the ground beneath the slab to settle unevenly.
Check Whether the Burrow Is Active First
Before you seal anything, you need to know if a groundhog is currently living under the shed. Loosely stuff newspaper or leaves into each entrance hole you can find. Check back after 48 hours. If the material has been pushed aside, the burrow is active and you’ll need to evict the animal before sealing up.
Timing matters. Groundhogs mate in March and April shortly after emerging from hibernation, and pups are born about 30 to 32 days later. The young don’t leave the den until roughly 33 days old and aren’t weaned until around 42 days. If you seal a burrow between late March and mid-June, you risk trapping helpless pups inside. Late summer through fall, after the young are mobile and before hibernation begins, is the safest window for exclusion work.
Evict Groundhogs With a One-Way Door
A one-way exclusion door lets the groundhog walk out but prevents it from re-entering. You can buy or build one from hardware cloth shaped into a tube with a hinged flap that swings outward only. Mount it directly over the main entrance hole.
The critical step: every other entrance must be sealed at the same time you install the door. If you leave secondary holes open and plan to “get to them later,” the groundhog will immediately circle around and re-enter through one of those gaps. Once all other openings are blocked and the one-way door is in place, the animal will try to dig back in for a day or two, then give up and relocate. You can remove the door and permanently seal that final opening after about a week of no activity.
Install an L-Footer Wire Mesh Barrier
This is the permanent fix. An L-footer is a trench-mounted wire barrier that runs along the base of your shed, with the bottom portion bent outward at 90 degrees underground. When a groundhog digs down along the shed’s edge, it hits the vertical section. When it tries to dig under the vertical section, it runs into the horizontal foot. Most animals give up at that point.
Materials You Need
- Hardware cloth: Use heavy-gauge galvanized welded wire with 1/2-inch mesh openings. Thin chicken wire deforms easily and won’t hold up against a determined digger.
- Trench dimensions: Dig 12 inches deep and 12 inches wide along the exterior perimeter of the shed. In sandy or loose soil, go deeper: 18 inches on both dimensions.
- Fasteners: Galvanized screws with fender washers or masonry anchors to attach the mesh to the shed’s frame or foundation.
Step-by-Step Installation
Start by digging your trench along the full perimeter of the shed, staying right against the exterior edge. Cut your hardware cloth so you have enough material to extend from above ground level (a few inches up the side of the shed) down into the 12-inch trench, plus an additional 12 inches to bend outward as the horizontal footer.
Bend the bottom of the mesh outward at a 90-degree angle before placing it in the trench. The vertical portion should sit flush against the shed’s base, and the horizontal “L” should extend away from the shed along the bottom of the trench. Secure the top edge of the mesh to the shed using screws and washers. Backfill the trench with the excavated dirt, packing it firmly as you go. The entire barrier ends up buried and invisible once the soil is back in place.
If your shed sits on concrete blocks or a poured slab, you can anchor the mesh directly to the masonry with concrete screws. For sheds on wooden skids, screw into the wood framing. The goal is a continuous, gap-free barrier with no loose edges a groundhog could pry up.
Fill Abandoned Tunnels to Prevent Collapse
Once the groundhog is gone and your barrier is installed, the empty tunnels under the shed can still cause problems. Voids in the soil may lead to settling or sinking over time, especially under a concrete slab.
For most homeowners, the simplest approach is to pack gravel into the tunnel openings as deeply as you can reach. Gravel compacts well, drains water, and resists future digging better than loose soil. For sheds on concrete slabs where you’re worried about structural settling, a mud-jacking company can pump grout into the voids under pressure to fill the entire tunnel network. Be cautious with this approach, though. Pumping too aggressively can actually lift the slab and crack it. Start conservatively and let the material settle.
For smaller tunnel systems, a combination of gravel packed in tightly and dirt tamped on top is usually sufficient.
Deterrents That Help (and Some That Don’t)
Certain secondary measures can make your yard less appealing to groundhogs, though none work as a standalone solution the way a buried barrier does.
Keeping vegetation trimmed short around the shed removes cover that groundhogs rely on for safe movement. They prefer not to cross open ground where they’re visible to predators. Removing brush piles, tall weeds, and ground-level hiding spots within 20 feet of the shed makes the area less attractive. If you have a vegetable garden nearby, that’s likely what drew the groundhog to your property in the first place, and fencing the garden with the same L-footer method keeps them out of both areas at once.
Commercial granular repellents and castor oil-based sprays are widely sold for groundhog control. They may cause a groundhog to avoid a treated spot temporarily, but the effect fades after rain and rarely convinces an animal to abandon an established burrow. Ammonia-soaked rags stuffed into burrow entrances can irritate the animal enough to push it out in the short term, but this is a nudge, not a solution. Use it alongside a one-way door, not in place of one.
Know Your Local Trapping Laws
If exclusion isn’t working or you’d rather have the animal removed directly, be aware that trapping and relocation laws vary significantly by state. In New York, for example, it is illegal to live-trap a groundhog and release it anywhere other than the property where it was captured. Relocating wildlife can spread diseases like rabies and causes significant stress to the animal. Most states require you to hire a licensed nuisance wildlife control operator for removal. Check your state wildlife agency’s website before setting any traps, because penalties for illegal relocation can be surprisingly steep.