Groundhog Fence Height in Canada: What Actually Works

Understanding Groundhog Behaviour

Before you pick a fence height, it helps to understand what you are dealing with. Groundhogs (Marmota monax) are found across most of southern Canada, from British Columbia through Ontario and into the Maritimes. They are built for two things: digging and eating. A single groundhog can excavate a burrow system spanning 14 metres (45 ft) with multiple entrances, moving hundreds of kilograms of soil in the process.

Key facts that affect fencing decisions:

• They're diggers first. Groundhogs can burrow 1.5 m (5 ft) deep. A fence that sits on top of the soil is essentially a suggestion.
• They can climb. Most people don't expect it, but groundhogs will scale rigid wire fencing up to about 900 mm (3 ft) if they're motivated enough by what's on the other side.
• They're stocky but surprisingly flexible. An adult can squeeze through a gap as small as 100 mm (4 in.) wide.
• They're seasonal. Most damage happens from April through October. By November they're hibernating, but the burrows they've dug remain, and other animals use them.

The Ideal Fence Height for Groundhogs

The short answer: at least 900 mm (3 ft) above grade, and 1,200 mm (4 ft) is better. If you're protecting a high-value vegetable garden or want maximum peace of mind, go to 1,200 mm and add a floppy top extension. Browse the hog wire fence panels collection to find the right panel height and mesh size for your project before you start digging.

Here is why that range works:

• Groundhogs rarely attempt to climb past 900 mm on rigid fencing. At 1,200 mm, you have exceeded their comfortable climbing range by a wide margin.
• This height also provides useful deterrence against rabbits, skunks, and raccoons, the supporting cast of garden raiders across Canada.
• For context, this is a purpose-built critter fence height. If you're also building a property-line fence, check your municipal bylaws. Many Canadian municipalities cap rear-yard fencing at 1,800 mm (6 ft) and side-yard at 1,200 mm (4 ft), but rules vary widely. Always confirm with your local building authority.

A note on building codes: if your groundhog fence also serves as a guard rail (for example, around a raised deck or retaining wall), the National Building Code of Canada (NBC) has specific requirements for guard height and opening size. Confirm those requirements with your provincial or municipal building authority before you build.

Below Grade: The Part Most People Skip

This is where most groundhog fences fail. You can build a beautiful 1,200 mm fence, and a determined groundhog will simply dig under it in an afternoon. The fix is a buried L-shaped footer.

How to Build an L-Footer

1. Dig a trench along the fence line, 300 mm (12 in.) deep and 300 mm wide on the exterior side.
2. Bend the bottom of your wire mesh outward at a 90-degree angle to form an "L" shape, so 300 mm of mesh extends horizontally underground.
3. Backfill the trench and compact the soil.

When the groundhog digs down along the fence, it hits the horizontal mesh and cannot get past it. They do not think to back up and dig further out. The L-footer is the single most effective groundhog deterrent you can add, and it is almost impossible to retrofit later. Get it right the first time.

Mesh Size and Wire Gauge

Mesh Opening Size

• 75 mm x 75 mm (3 x 3 in.) or smaller: blocks adult groundhogs.
• 50 mm x 50 mm (2 x 2 in.) or smaller: blocks juveniles and most other garden pests.
• Anything larger than 100 mm x 100 mm (4 x 4 in.) and you are building a groundhog turnstile, not a fence.

Wire Gauge

This is where long-term value separates from short-term savings. Thin 14-gauge or 11-gauge wire bends and deforms under sustained pressure from digging animals. Groundhogs gnaw and push. They will exploit any flex in the mesh to create a gap. And thin wire buried in damp Canadian soil corrodes faster, especially at weld points.

BarrierBoss uses 6-gauge wire, thick enough to resist gnawing and sustained animal pressure. More importantly, our panels are electrogalvanized after welding, then dip-coated. That sequence matters: the zinc coating covers the welds just as thoroughly as every other inch of wire. Competitor panels typically use pre-galvanized wire, which means the welding process burns the zinc off at every intersection. Those bare-steel weld points are the first spots to rust, and underground, where your L-footer lives, that corrosion is accelerated by constant moisture contact.

The result: BarrierBoss backs the wire and finish with a 40-year warranty. Leading competitors warrant theirs for 15 years. Underground, that difference shows up in about five.

Climb-Proofing Your Fence

• Floppy top extension: Add 300 mm (12 in.) of unsupported mesh at the top of the fence, angled outward at roughly 45 degrees. When a groundhog reaches the top and puts weight on this section, it bends back toward them. They cannot get over it. This is the same principle used in commercial wildlife exclusion systems.
• Avoid horizontal rails near the top: Horizontal framing gives them footholds. A smooth vertical surface or outward-angled mesh is much harder to grip.
• Rigid lower section: The first 900 mm should be taut, rigid, and firmly attached to posts. You do not want flex that a climbing animal can use as a launch point.

For property-line fences or areas where aesthetics matter alongside critter control, corrugated metal fence panels in 26-gauge HDP steel with HDP NoFade paint offer a solid visual barrier that groundhogs can neither climb nor see through, removing the food-motivation trigger entirely.