Pavement ant

What pavement ants look like

Pavement ants are small, roughly 3 to 4 mm long, and brown to nearly black with paler legs and antennae. Under magnification the head and thorax carry fine parallel grooves running front to back, and there are two small spines on the back of the thorax, which separates them from most other ants of similar size. The waist has two nodes. Workers are all one size, unlike carpenter ants, and they move in slow, deliberate lines rather than darting. Winged reproductives are considerably larger and often appear indoors in spring, which alarms people who assume they are termites. They are not. Pavement ants are one of the most common ants on Ontario properties and are easy to overlook until a trail forms.

Signs you have pavement ants

• Soil craters. Small volcano shaped mounds of fine excavated grit pushed up through cracks in driveways, walkways, patio joints and garage floors.
• Foraging lines. Persistent narrow trails along expansion joints, baseboards, foundation edges and the underside of counters.
• Kitchen activity. Ants working crumbs, pet bowls, grease around the stove and sweet spills, often coming from a single entry point.
• Pavement battles. Large numbers of ants massed in a shifting cluster on a driveway or path in spring, where two neighbouring colonies are fighting.
• Grit indoors. Fine sand or soil appearing repeatedly along a basement wall, under a slab edge or at the base of a door frame.
• Spring swarmers. Winged ants at basement windows and light fittings on warm days, which means a mature colony is nesting close by or under the slab.

Cratered joints outside plus an indoor trail usually means the nest is under the concrete.

Why pavement ants turn up around Ottawa and Toronto properties

Pavement ants are named for where they live. They nest in soil under hard surfaces, and our cities are covered in them: driveways, sidewalks, interlock patios, garage slabs, basement floors, porch pads, curbs and the gravel base under walkways. Concrete holds heat, sheds rain away from the nest and gives the colony a hard ceiling that nothing can dig through, which is close to ideal. Ontario freeze and thaw cycles crack and lift slabs every winter, opening fresh routes each spring, and settled interlock joints do the same. Once a colony is established outdoors, foraging workers follow warmth and food into the building through slab cracks, sill gaps, utility penetrations and door thresholds. Kitchens, pantries and pet feeding areas give them grease, sugar and protein, and a basement slab crack lets them work indoors through the winter.

Are pavement ants dangerous?

Honestly, pavement ants are a nuisance rather than a hazard. They can sting, but the sting is weak and they almost never do it, and they are not aggressive toward people or pets. They do not transmit disease in any meaningful way. The practical concern is contamination rather than infection: ants crossing bins, drains and outdoor surfaces before walking over food, counters or pet bowls is unhygienic, and an ant trail through a pantry can ruin opened packaging. The property risk is also modest. They do not damage wood or wiring. Over time, persistent excavation under interlock, patio stones and walkway edges can undermine sand bedding and cause pavers to settle unevenly, and the soil pushed up through joints is untidy, but nothing structural is at stake. Large indoor numbers are the main reason people call.

How to keep pavement ants away

• Seal cracks in driveways, walkways, garage slabs and basement floors, and repoint or re-sand settled interlock joints.
• Close gaps where utilities, pipes and cables pass through the foundation, and fit or replace worn door thresholds and sweeps.
• Keep food in sealed containers, wipe up grease and sugar promptly and clean under appliances where crumbs collect.
• Lift pet bowls between meals, and keep pet food in a closed container rather than an open bag.
• Rinse recycling, keep bin lids closed and move bins off the slab beside the house where possible.
• Keep a clear strip of gravel or bare soil against the foundation instead of mulch, and move stacked stone and lumber away from the wall.

Sealing entry cracks and removing food sources solves most pavement ant complaints.

How GO! Pest Control handles pavement ants

• Inspection. We follow the trails back to their entry points, check the slab and joint cracks outside and locate the nests under the hard surfaces.
• Treatment. We use baits that workers carry back to the colony, combined with a targeted perimeter application where it will do the most good, rather than surface spraying trails.
• Exclusion. We identify the cracks, thresholds, weep holes and utility penetrations that let ants in, and close what can be closed on site.
• Follow-up. We come back to confirm the colony has collapsed and re-bait where trails reappear, since nests under slabs can take more than one visit.
• Advice. We go through the food storage, cleaning and outdoor habits that are keeping the trail supplied.

We are licensed, insured and bonded, and we work in homes, apartments, condos and businesses across the Toronto GTA, Ottawa and Hamilton.

Common questions about pavement ants