Carpenter Ants vs Pavement Ants in the GTA

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It is easy to dismiss both ants as the same problem. They are small, black, and running in the same line toward your crumbs. But getting the identification wrong costs money. Carpenter ants can cause structural damage that requires thousands in repairs. Pavement ants are just an annoyance. Here is how to tell the difference and why it matters for your GTA home.

Visual Differences

Size is the first clue. Carpenter ants are the largest ant species in Ontario, ranging from 1.5 to 2.5 cm. Pavement ants are tiny, only 2 to 4 mm. If you can see the ant clearly and it looks big, it is probably a carpenter ant.

Look at the body shape. Carpenter ants have a rounded, arched thorax when viewed from the side. Pavement ants have a flattened thorax with distinct grooves running down the head. The carpenter ant thorax is smooth and uniform.

The abdomen connection. Carpenter ants have a smooth, constricted waist between the thorax and abdomen. On pavement ants, you can see the petiole (the tiny segment connecting the two body parts) more clearly.

Behaviour Differences

Where they nest. Carpenter ants nest in wood. They excavate galleries in moist, decaying timber to build their colony. Common nesting sites in GTA homes include roof eaves, window frames, deck posts, and bathroom walls where water damage has softened the wood.

Pavement ants nest under concrete, between paving stones, and in foundation cracks. They prefer the gaps between your patio stones and the space under your basement slab. They do not enter your home to nest but will forage for food inside.

Signs of Carpenter Ant Damage

• Frass. This is the sawdust-like material carpenter ants push out while excavating galleries. You will find small piles near wooden structures, baseboards, and window sills. Frass may contain dead ant parts.
• Hollow-sounding wood. Tap on wooden beams and door frames. If they sound hollow, carpenter ants may have excavated the interior.
• Swarmers. In spring, winged carpenter ants (reproductive swarmers) emerge from established colonies. If you see winged ants inside your home, you have an established nest nearby.
• Rustling sounds. In quiet moments, you may hear faint scratching inside walls. This is the ants moving through their galleries.

Why Correct ID Matters

Pavement ants are an annoyance. They can be eliminated with perimeter sprays and baits without opening walls. They do not return if you seal entry points and keep food sealed.

Carpenter ants require a different approach. You must find the nest, which is often inside wall voids. Gel bait is more effective than sprays because foragers carry the bait back to the colony, eventually eliminating the queen. Sprays only kill what they contact directly and do not reach the nest.

Treatment for Each

Carpenter ants: Professional treatment includes thorough inspection to locate the nest, gel bait application in cracks and along trails, possible drilling into walls to reach the colony, and follow-up visits. Expect $300 to $600 for a GTA home.

Pavement ants: Perimeter treatment with residual spray, bait placement at entry points, and sealing gaps around pipes. Expect $175 to $300.

Prevention

• Fix moisture problems. Carpenter ants need moist wood. Repair leaking roofs, gutters, and pipes.
• Store firewood at least 20 feet from the house. Woodpiles are prime carpenter ant habitat.
• Seal entry points around windows, doors, and pipes.
• Keep vegetation trimmed back from the foundation.
• Remove dead stumps and rotting wood from your property.

Frequently Asked Questions

How do I tell carpenter ants from pavement ants?

Carpenter ants are larger, up to 2.5 cm, with a rounded thorax. Pavement ants are smaller, 2-4 mm, with a flat thorax and grooves on the head.

Can carpenter ants cause structural damage?

Yes. Carpenter ants excavate wood to build nests. Repeated infestations can compromise structural beams, door frames, and window sills in GTA homes.

Where do carpenter ants nest in GTA homes?

Carpenter ants nest in moist, decaying wood. Common sites include roof eaves, window sills, deck posts, and bathroom walls.

Do pavement ants damage homes?

No. Pavement ants are a nuisance but do not damage structures.

How much does carpenter ant treatment cost in the GTA?

Professional carpenter ant treatment runs $300 to $600. Pavement ant treatment runs $175 to $300.

Not sure what ant you have? Get free quotes from licensed ant control professionals who can identify the species and recommend the right treatment.