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Field MiceCarpenter ant exterminator in Montreal, down to the nests hidden in your walls
The whole colony treated, from the walls to the foundation.
With a fixed online price or a free quote and a written warranty on your invoice, SOS Extermination inspects your home with a thermal camera and identifies the species before treating the main nest and its satellite nests.
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JOURNAL DE MONTRÉAL
24 HEURES
PROTÉGEZ-VOUS
URBANIA
98,5 FM
LES AFFAIRES
TRUSTINDEX
BARK
HOMESTARS
INSPECTION MTL
JOURNAL DE MONTRÉAL
24 HEURES
PROTÉGEZ-VOUS
URBANIA
98,5 FM
LES AFFAIRES
TRUSTINDEX
BARK
HOMESTARS
INSPECTION MTL
Our carpenter ant control services
A 24/7 exterminator in Montreal, SOS Extermination treats carpenter ants (Camponotus), the large black ants that nest in wood, in houses, plexes, condos and businesses across Greater Montreal. For pavement ants, pharaoh ants and other species, see our ant exterminator service.
Main nest and satellite nests in the walls
A carpenter ant colony rarely lives in a single spot: the main nest, sometimes outdoors in a stump, a tree or damp wood, feeds satellite nests set up in walls, attics or the framing. We place targeted baits along the workers’ trails, and they carry them back to the queen and the larvae. Once the queen is eliminated, the colony collapses.
Exterior perimeter treatment
The exterior perimeter treatment protects the foundation, door sills and cracks that carpenter ants use to get into the house. It targets the workers travelling between the outdoor nest and the building along branches, wooden decks or firewood. Our technicians apply Health Canada-registered products in a targeted way.
Fixing moisture and damaged wood
Carpenter ants dig their galleries in wood that is damp, rotten or weakened by a water leak. During the inspection, we locate these areas (window frames, roof, crawl space, basement) and tell you what needs fixing: a leak, damaged wood to replace, mulch to move away from the foundation, branches to trim. Sealing accessible openings is part of our exclusion measures.
Carpenter ants in plexes and apartment buildings
In a plex or apartment building, a colony moves from one unit to another through shared walls. We recommend including the units next to the activity area in the inspection, with the landlord’s or property manager’s approval. To find out who pays for extermination in an apartment building, see our guide.
Our 5-step carpenter ant treatment method
Our method follows integrated pest management (IPM): the price is known up front, then every step on site targets the entire colony, from the queen to the workers.
01Price from the calculator or a free quote
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The online calculator gives you a fixed price in about 60 seconds, with no sign-up. Prefer a visit? Request a free quote: you know the price before the treatment.
02Thermal camera inspection
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The technician looks for sawdust (frass) at the base of walls and baseboards, discarded wings near windows and the workers’ trails, which are most active in the evening. The thermal camera detects temperature variations in walls, ceilings and floors: it helps locate nesting areas and moisture without opening walls. See how our thermal camera inspection works.
03Identifying carpenter ants
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Workers measure 6 to 13 mm and the queen can reach 2.5 cm, much bigger than pavement ants. Confirming the species points the treatment at the wood of the structure and avoids confusing carpenter ant damage with termite damage.
04Targeted colony treatment
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We treat the main nest, the satellite nests and the exterior perimeter based on what the inspection revealed. An insecticide sprayed on visible ants kills the foraging workers and leaves the queen laying eggs safely, which is why we rely on baits and targeted residual treatment. Home remedies for carpenter ants run into the same limits when the nest is hidden in the structure.
05Prevention, follow-up and written warranty
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After the treatment, you receive our prevention tips: firewood away from the house, stumps removed, leaks repaired. The written warranty on your invoice specifies the follow-up and the conditions for a return visit.
Carpenter ants in your walls?
Get your fixed price in about 60 seconds, with no sign-up or commitment.
Carpenter ant exterminator cost
Treating a carpenter ant colony costs $300 to $1,250 in Montreal, according to our July 28, 2026 price guide (for reference only). The price varies with the age of the colony, the areas affected, the size of the property and the type of building. The thermal camera and the written warranty are included; payment plans are available. Get a fixed price with our online price calculator or see our 2026 price guide by pest.
Signs of a carpenter ant infestation
Four signs call for an inspection: large black ants in the house in the evening, fine sawdust at the base of walls, scratching noises in the walls at night and winged ants indoors. In spring, a mature colony releases winged ants (swarmers); in winter, finding them indoors often signals a nest in the heated structure. Each sign is detailed in our article on the signs of a carpenter ant infestation.
Our certified technicians answer 24/7, 365 days a year: in an emergency, a same-day visit is possible; scheduled visits take place within 24 to 72 hours.
Every carpenter ant extermination uses Health Canada-registered products and ends with a written warranty on the invoice.
Our unmarked vehicles keep the service discreet in front of your home or business.
Carpenter ants across Greater Montreal
We treat carpenter ants on the island as well as on the South Shore and North Shore, including in Plateau-Mont-Royal, Rosemont-La Petite-Patrie, Hochelaga-Maisonneuve, Laval, Longueuil and Brossard. A single number, 514 501-2076, answers day and night for the whole territory.
FAQ: carpenter ant exterminator in Montreal
How much does a carpenter ant exterminator cost in Montreal?
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Our 2026 price guide puts the treatment of a carpenter ant colony between $300 and $1,250, for reference only. A recent colony caught early costs less than a colony established for several seasons with satellite nests in several walls. The online calculator gives a fixed price in about 60 seconds. You can also request a free quote.
How do I recognize a carpenter ant?
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It is the largest common ant in Quebec: workers measure 6 to 13 mm, with a wide head and strong mandibles. The pavement ant is much smaller. A carpenter ant also leaves fine sawdust near its galleries. A professional exterminator confirms the species during the inspection, before any treatment.
Do carpenter ants eat wood?
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No. They dig into wood to build their galleries and nests, then push the sawdust out of their galleries. Termites, on the other hand, feed on wood. Carpenter ant damage still progresses: over time, the galleries can reach beams and framing, especially where the wood stays damp.
Winged ants in the house in winter: is it serious?
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It is a warning sign to take seriously. In winter, winged carpenter ants indoors usually point to a mature colony living in the heated structure, such as a damp wall or ceiling. A thermal camera inspection then helps locate the satellite nest before it spreads to other rooms.
Why treat the nest rather than the visible ants?
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The ants you see are workers looking for food. The queen, the larvae and most of the colony stay in the main nest and the satellite nests. A product sprayed on their trails kills those workers and leaves the colony intact. Targeted baits, carried back to the nest by the workers themselves, reach the queen.
Is carpenter ant treatment guaranteed?
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Yes. Every carpenter ant treatment ends with a written warranty. Its length and conditions vary with the treatment and the pests covered. The written warranty on your invoice specifies the follow-up and the conditions for a return visit. Keep this invoice: it serves as a reference if activity resumes in the following months.
Do I need to repair the wood after extermination?
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Yes, as soon as the source of moisture is known. Wood that stays damp or rotten attracts a new colony, even after a successful treatment. Have the leak repaired, replace the damaged wood and ventilate the crawl space or attic. We show you the areas to fix during the inspection so you can get rid of carpenter ants for good.
Ant exterminator or carpenter ant exterminator: what is the difference?
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Our ant exterminator service covers pavement ants, pharaoh ants and odorous house ants, which are mainly looking for food. Carpenter ants require a more thorough inspection because they nest in the wood of the structure. Our technicians identify the species during the inspection and apply the matching treatment.
Your carpenter ant exterminator, 24/7
Describe the signs you have noticed and get your free quote, with no commitment.
What our clients say about us
Je gère plusieurs immeubles et j'ai trouvé SOS Extermination via leur calculateur de prix en ligne. Super pratique. J'avais une grosse urgence de fourmis charpentières dans un bloc sur le Plateau-Mont-Royal. Je les ai appelés et en même pas 24h, Oussama était sur place avec sa caméra thermique. C'était impressionnant de voir tous les nids satellites cachés dans les murs ! Bonne job les gars, merci
Mariam HajajVerified Google reviewOn a eu une grosse invasion de fourmis charpentières dans mon triplex à Rosemont dernièrement. Il y en avait vraiment partout, même des grosses avec des ailes qui volaient ! J'ai appelé l'équipe de SOS Extermination et honnêtement, ils ont réglé le problème comme par magie. Il n'y a plus aucune trace. Un super bon service, je les recommande sans hésiter.
Gabrielle AllaireVerified Google reviewMy neighbour recommended Sos-extermination for our carpenter ant problem here in the West Island. Honestly I'm so glad I listened to her! We were freaking out but they passed by super fast to do the treatment. Since then there hasnt been a single trace of them, they completly disappeared.
JCVerified Google reviewExcellent service le propriétaire et son équipe travaille avec tant de professionnalisme et de bienveillance. On voit qu'il savent et qu'ils sont des experts dans le domaine. Les prix sont abordables, ils peuvent accomoder les payments (plan de payment). Ils mon offert une garantie de plus puisque mon cas étais un peu complexe…
Unknown PersonneVerified Google reviewTrès bon traitement de souris, c'est du très bon travail. Merci.
Hamza GormiVerified Google reviewJe gère plusieurs immeubles et j'ai trouvé SOS Extermination via leur calculateur de prix en ligne. Super pratique. J'avais une grosse urgence de fourmis charpentières dans un bloc sur le Plateau-Mont-Royal. Je les ai appelés et en même pas 24h, Oussama était sur place avec sa caméra thermique. C'était impressionnant de voir tous les nids satellites cachés dans les murs ! Bonne job les gars, merci
Mariam HajajVerified Google reviewOn a eu une grosse invasion de fourmis charpentières dans mon triplex à Rosemont dernièrement. Il y en avait vraiment partout, même des grosses avec des ailes qui volaient ! J'ai appelé l'équipe de SOS Extermination et honnêtement, ils ont réglé le problème comme par magie. Il n'y a plus aucune trace. Un super bon service, je les recommande sans hésiter.
Gabrielle AllaireVerified Google reviewMy neighbour recommended Sos-extermination for our carpenter ant problem here in the West Island. Honestly I'm so glad I listened to her! We were freaking out but they passed by super fast to do the treatment. Since then there hasnt been a single trace of them, they completly disappeared.
JCVerified Google reviewExcellent service le propriétaire et son équipe travaille avec tant de professionnalisme et de bienveillance. On voit qu'il savent et qu'ils sont des experts dans le domaine. Les prix sont abordables, ils peuvent accomoder les payments (plan de payment). Ils mon offert une garantie de plus puisque mon cas étais un peu complexe…
Unknown PersonneVerified Google reviewTrès bon traitement de souris, c'est du très bon travail. Merci.
Hamza GormiVerified Google reviewAprès avoir essayé d'autres compagnies sans succès pour des fourmis charpentières dans mon triplex à Ahuntsic, j'ai trouvé SOS. Déjà, leur calculateur de prix en ligne est super transparent ! Oussama et Yannick sont venus et j'ai capoté : leur caméra thermique voit directement dans les murs ! Problème réglé en quelques jours. J'ai attendu la fin de ma garantie d'un an pour faire cet avis…
Vitélina Saint-PhardVerified Google reviewLe meilleur service de gestion parasitaire dans Hochelaga Est et le reste de Montréal. En tant que gestionnaire, j'apprécie leur transparence : le calculateur de prix virtuel donne un devis fixe en 60 secondes. Pas de niaisage. Pour les fourmis charpentières et les rats, ils utilisent la caméra thermique (incluse partout) pour trouver l'humidité et les nids cachés…
Kaotar OVerified Google reviewLes fourmis charpentieres de Hochelaga a Montréal sont finalement game over je recommande sans hésiter !!!
Jojo ShaolyneVerified Google reviewReally satisfied with the result. They are expert in their field and you'll be impressed by the result. Highly recommended!
Hadi EmamiVerified Google reviewVery good team
MR BVerified Google reviewAprès avoir essayé d'autres compagnies sans succès pour des fourmis charpentières dans mon triplex à Ahuntsic, j'ai trouvé SOS. Déjà, leur calculateur de prix en ligne est super transparent ! Oussama et Yannick sont venus et j'ai capoté : leur caméra thermique voit directement dans les murs ! Problème réglé en quelques jours. J'ai attendu la fin de ma garantie d'un an pour faire cet avis…
Vitélina Saint-PhardVerified Google reviewLe meilleur service de gestion parasitaire dans Hochelaga Est et le reste de Montréal. En tant que gestionnaire, j'apprécie leur transparence : le calculateur de prix virtuel donne un devis fixe en 60 secondes. Pas de niaisage. Pour les fourmis charpentières et les rats, ils utilisent la caméra thermique (incluse partout) pour trouver l'humidité et les nids cachés…
Kaotar OVerified Google reviewLes fourmis charpentieres de Hochelaga a Montréal sont finalement game over je recommande sans hésiter !!!
Jojo ShaolyneVerified Google reviewReally satisfied with the result. They are expert in their field and you'll be impressed by the result. Highly recommended!
Hadi EmamiVerified Google reviewVery good team
MR BVerified Google review