Identification
| Trait | Detail |
|---|---|
| Size | Workers commonly about 6–12 mm; majors can look larger. |
| Colour | Often all black; some forms show reddish-brown on thorax or legs. |
| Thorax | Single node waist; dorsum of thorax evenly rounded—no sharp spines. |
| Wings | Swarmers have two pairs; forewings longer; shed wings on sills are a clue. |
| Frass | Coarse sawdust-like shavings mixed with insect parts may appear near galleries. |
| Similar species | Moisture ants and field ants confuse homeowners; professional ID helps when colour alone is ambiguous. |
Carpenter ants (Camponotus spp.) are the large ants associated with water-damaged wood in Pacific Northwest homes. In Greater Vancouver they exploit softened fascia from gutter leaks, posts touching soil, and deck stringers wicking rain. Workers are mostly nocturnal on interior trails; daytime sightings near kitchens can still occur when colonies are large or disturbed.
Behaviour & Habits
Colonies prefer moist or hollow cavities: wall voids with pipe leaks, attic sheathing under failed vents, and window sills with chronic condensation. They do not eat wood like termites; they excavate galleries to nest. Satellite nests can form in drier wood once the parent site establishes. Foraging trails may follow plumbing chases, exterior corners, and tree branches touching siding.
Swarming typically happens spring into summer on warm evenings; shed wings on floors or sills suggest reproductive activity nearby. Noise from active galleries can sound like faint rustling when the house is quiet.
Health & Property Risks
⚠ Health risk — professional removal recommended. While bites are uncommon, carpenter ant excavation weakens structural members and often signals hidden moisture that feeds mold.
Primary property risk is gallery expansion in load-bearing or connection points—posts, beams, rim joists—especially where rot already softened fibers. Cosmetic damage includes blistered paint from moisture and pile of frass in closets. Health adjacent risks tie to chronic damp that supports mold, not the ants themselves as disease vectors.
Prevention
- Repair roof leaks, failed flashing, and clogged gutters that wet wood repeatedly.
- Keep soil and mulch off siding; maintain clearance under decks.
- Ventilate crawlspaces and bathrooms; fix chronic pipe drips inside walls.
- Trim branches and vines that touch the roofline or siding.
- Replace rotted fascia or deck boards before ants re-establish galleries.
- Store firewood off the ground and away from exterior walls.
How We Treat Carpenter Ants
Inspection maps nest sites, moisture sources, and trail routes. Treatment targets voids and colony areas using methods appropriate to the structure and label, paired with recommendations—or contracts—for carpentry and moisture repair when wood is structurally compromised. Follow-up checks activity along former trails and new frass.
For colony-level work in Greater Vancouver, see our ant control service and book an inspection so nest location drives the plan rather than perimeter-only guesses.
Frequently Asked Questions Q: Do carpenter ants eat my house like termites?
A: No—they tunnel; they do not consume cellulose for food. Moist wood still must be fixed.
Q: Are big black ants always carpenters?
A: Not always; size and thorax shape help, but similar ants exist—ID on site matters.
Q: Can I spray once and finish?
A: Satellite nests and moisture often require sequenced visits and repairs.
Q: Why at night?
A: Many foraging peaks are nocturnal; daytime kitchens can still show workers when colonies are large.
Professional Ant Control
Carpenter Ant problems in Greater Vancouver require a systematic approach — inspection of the full property, elimination of the root cause, and documented follow-up. Our ant control service covers all of this.
View Ant Control