Carpenter Ants in Quebec Co-ownership: Who Pays?

Carpenter ants can damage a building’s structure and affect residents’ comfort. In divided co-ownership, the question quickly arises: who pays for extermination and repairs? The answer depends mainly on the source of the infestation and what is provided for in the declaration of co-ownership and the Civil Code of Quebec (C.C.Q.).

For the board of directors and co-owners, a methodical approach makes it possible to allocate costs fairly, document decisions in the minutes and avoid unnecessary disputes. Here is a practical guide to assessing responsibilities, choosing the right experts and preventing the ants from returning.

First, remember that carpenter ants mainly settle in damp or damaged wood. The infestation is therefore often a symptom of a maintenance problem (infiltration, condensation or a thermal bridge) that may affect common portions or private portions.

Identify and locate the infestation

Allocating costs starts with a proper investigation. The board of directors must determine where the ants are coming from and which building components are affected.

Common indicators:

• Sawdust (frass) at the base of walls, along baseboards or around door frames.
• Ant trails, especially in the evening, near windows, balconies or service entrances.
• Spongy woodwork, a damp odour or blistering paint.
• Light scratching sounds inside partitions when they are tapped.

Good investigation practices:

• Have the property inspected by a licensed exterminator, who will prepare a report specifying the species, areas of activity and openings to be treated. Check the licence on the RBQ website.
• Compare these findings with the maintenance records (maintenance logbook / contingency fund study) and recent inspection reports.
• Look for sources of water: window seals, roofs, flashings, mechanical exhaust outlets and plumbing stacks.

Useful resources:

• LégisQuébec – Civil Code of Quebec (C.C.Q.)
• RBQ – Check a contractor’s licence
• RGCQ – Co-ownership resources

For ongoing operational support (vendor management, work orders and follow-ups), visit multiRent’s Services – Operations Management page: https://www.multirent.ca/services/#gestion-des-operations

Who pays? General rules under the declaration and the C.C.Q.

In co-ownership, the basic principle is that each co-owner contributes to the common expenses according to the relative value of their fraction (see section 1064 of the C.C.Q.). This means that when a problem concerns common portions, the expense is generally assumed by the syndicate through the common expenses (condo fees). When the source is located in a private portion and results from a maintenance deficiency attributable to the co-owner, that co-owner generally assumes the expense.

What must be analysed before assigning the invoice:

• Source and extent: Is the nest located in a load-bearing structure, a balcony, a party wall (common portions) or a kitchen cabinet box (often a private portion)?
• Causal link: Was the infestation caused by infiltration from a roof membrane (common) or by a leak from a private appliance (for example, an improperly connected dishwasher)?
• Provisions of the declaration of co-ownership and the by-laws of the immovable: many declarations of co-ownership provide detailed allocations of responsibility for maintaining and repairing ambiguous components (windows, doors and balconies). These documents must be consulted first.
• Insurance: if an insurance claim is involved, the allocation of fault or negligence and the assignment of a deductible may apply (see the provisions of the C.C.Q., particularly those concerning the assignment of the deductible to the co-owner responsible for the loss under section 1074.1 of the C.C.Q., when the conditions are met).

In practice:

• Common portions (structure, framing, load-bearing walls, roofs, plumbing stacks and common insulation): the syndicate generally assumes the cost of extermination and restoration, paid through the common expenses.
• Private portions (interior finishes, built-in furniture and the co-owner’s appliances): the invoice often goes to the co-owner, especially if a maintenance deficiency created favourable conditions.
• Mixed areas (for example, windows and balconies): everything depends on the declaration of co-ownership. Some syndicates consider these components common portions for restricted use; others assign them to private portions. Check the declaration of co-ownership and the by-laws.

To read the text of the Civil Code of Quebec, visit LégisQuébec: https://www.legisquebec.gouv.qc.ca/fr/document/lc/CCQ-1991

Board of directors’ process: from notice to resolution

A clear procedure limits misunderstandings and protects the syndicate.

1. Open the file
   • Receive the report (email, maintenance form or call). Acknowledge receipt and request photos or videos.
   • Issue a notice of access to potentially affected units, with reasonable notice or immediately in an emergency.
2. Assessment and expertise
   • Retain a licensed exterminator to conduct an inspection and prepare a treatment plan. Request a written report locating the presumed source and specifying the required work.
   • If necessary, retain a building envelope expert to detect the source infiltration (roof, seals, flashings or air barrier).
3. Decision and allocation of costs
   • Analyse the declaration of co-ownership and the by-laws of the immovable. Document the reasoning (source, affected portions and applicable clauses).
   • Adopt a board of directors’ resolution authorizing the work, specifying the payer (syndicate or co-owner) and setting out the follow-ups. Record everything in the minutes.
4. Work and communication
   • Coordinate the extermination, followed by the repairs (drying, replacing affected wood and sealing). Prioritize the causes of dampness.
   • Inform co-owners about the interventions, timelines, access rules and instructions (pets and preparation of the premises).
5. Close-out and prevention
   • Archive reports, photos, invoices, correspondence and decisions.
   • Update the maintenance logbook / contingency fund study and, if necessary, incorporate targeted seasonal inspections.

For communication and follow-up templates, see the multiRent blog: https://www.multirent.ca/blogue/

Cost allocation: typical cases and reference points

The examples below provide general reference points. The declaration of co-ownership and technical expertise always take precedence.

Insurance note: if an insured loss results from the infestation (water damage, demolition or restoration), the deductible or part of the costs could be charged according to the rules of the C.C.Q. and the policy. See the C.C.Q. on LégisQuébec: https://www.legisquebec.gouv.qc.ca/fr/document/lc/CCQ-1991

Preventing carpenter ants: a maintenance plan

The best expense is often the one avoided through preventive maintenance.

Priority measures for the syndicate (common portions):

• Visually inspect the building envelope every spring and autumn (flashings, joints, sealants, drip edges, roof upstands, window supports and door thresholds).
• Keep a caulking and sealing program for mechanical and electrical penetrations up to date.
• Trim vegetation touching the cladding; keep wood from contacting the ground.
• Manage water: ground slopes, gutters, functioning drains and sealed discharge flaps.
• After any water damage, dry the area quickly and check the cavities.

Good practices for co-owners (private portions):

• Monitor appliance leaks (dishwasher, refrigerator and washing machine), silicone seals and traps.
• Avoid storing damp wood; keep baseboards accessible for periodic visual inspections.
• Promptly notify the board of directors of any sign of dampness, sawdust or ant trails.
• Allow access for inspection or treatment; follow the preparation instructions.

Choosing service providers:

• Retain properly licensed and insured contractors and exterminators. Check the licence with the RBQ: https://www.rbq.gouv.qc.ca/trouver-un-entrepreneur/
• Require written reports with photos, corrective recommendations and a realistic service warranty.

When selling a fraction, remember that a known infestation or structural repairs may have to be disclosed to the broker and the buyer. See the OACIQ – Seller’s Declaration: https://www.oaciq.com/fr/articles/la-declaration-du-vendeur

Quick FAQ

Q1. Can the board of directors require access to a unit for inspection or treatment?

Yes. When work required to preserve the building or ensure safety makes it necessary, reasonable access may be required. Prior notice is customary, except in an emergency.

Q2. Should all units be treated, or only the affected portion?

It depends on the exterminator’s treatment plan. Carpenter ants move around, so targeted treatment of adjacent areas and exterior entry points is often recommended.

Q3. Can a co-owner be reimbursed for extermination costs incurred independently?

This is possible if the source was in a common portion and the board of directors authorizes it after reviewing the evidence and the declaration of co-ownership. It is preferable to notify the board of directors before incurring any expense and wait for its instructions.

To structure prevention and intervention follow-ups, see multiRent’s operations management services: https://www.multirent.ca/services/#gestion-des-operations and compare the packages: https://www.multirent.ca/#forfaits

This article provides general information and does not constitute legal advice. Consult a lawyer or notary for your situation.

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