Mould: the complete guide to taking action

Is mould dangerous?

Mould in a dwelling isn't just a cosmetic problem: it's a real health risk. Mould spores released into the air can trigger allergic reactions, asthma, respiratory infections, and irritation of the eyes, skin, and airways. Prolonged exposure can worsen existing chronic conditions.

The most vulnerable people are young children, seniors, those with weakened immune systems, and anyone already dealing with respiratory problems such as asthma or COPD. In these groups, even moderate exposure can have significant health consequences.

Health Canada and Quebec's public health authority consider the presence of visible mould in a dwelling to be a factor of unfitness requiring intervention. If you find mould in your home, don't minimize the problem: it calls for prompt action.

Your landlord's obligations

The Civil Code of Québec requires the landlord to deliver a dwelling in a good state of habitability (art. 1910) and to maintain it in good condition throughout the lease (art. 1911). The presence of mould is a breach of these obligations when it results from a lack of maintenance, a structural problem, or a defect in the building.

In practical terms, if the mould is caused by water infiltration, inadequate ventilation, a plumbing problem, or a construction defect, it's the landlord's responsibility to fix the problem at their own expense. The tenant does not have to pay for structural repairs or tolerate an unfit dwelling.

Nor can the landlord claim ignorance of the problem once the tenant has notified them. As soon as you report the presence of mould in writing, the landlord has an obligation to act within a reasonable time. Their inaction is a fault that can give rise to remedies before the TAL.

How to document the problem

Documentation is your best ally if you eventually have to file an application with the TAL. Take dated photos of every area affected by mould, including reference points to show the extent of the problem. Photograph the same areas regularly to show how it develops over time.

Keep a written log of your observations: when you first noticed the mould, how it is spreading, and what health symptoms you or the members of your household have developed. Keep the receipts for any purchase related to the problem (air purifier, cleaning products, medical appointments).

If possible, request a municipal inspection and keep the report. An independent professional inspection report is also a valuable asset, although it comes at a cost. Keep all correspondence with your landlord: emails, texts, letters: proving that you informed them of the problem.

Reporting to the city and the authorities

Most Quebec municipalities have a housing sanitation inspection service. In Montreal, you can call 311 to report a mould problem and request a municipal inspection. The inspector can order the landlord to carry out the necessary work, on pain of fines.

For more serious cases, your regional CIUSSS and the public health authority can intervene. These bodies have the power to assess the health impact of the situation and issue binding recommendations. If a doctor finds health problems linked to mould, request a medical report: it will be important evidence.

Reporting to the authorities creates an official record of the problem and considerably strengthens your file if you take the matter to the TAL. Even if the inspection doesn't lead to immediate action, the report is independent proof of the condition of the dwelling.

Sending a demand letter

If your landlord doesn't respond to your verbal or written reports, sending a demand letter (mise en demeure) is the next step. This formal document gives them a reasonable deadline (generally 10 to 15 days) to begin the work to fix the mould, on pain of proceedings before the TAL.

Your demand letter must describe the problem precisely, the dates of your previous reports, and the impact on your health and your peaceful enjoyment of the dwelling. Cite the relevant articles of the Civil Code (1854, 1910, 1911) and attach copies of your photos and inspection reports if you have them. Our demand letter template for mould or an unfit dwelling already brings these elements together.

Send your demand letter by a method that provides proof of receipt: registered mail, a bailiff, or certified email. Proof of sending and receipt is essential if you eventually have to take the matter to tribunal.

Your remedies at the TAL

If your landlord doesn't act on your demand letter, you can file an application with the TAL. Several types of remedies are possible: you can request an order requiring the landlord to carry out the repairs, a retroactive rent reduction for the period during which you endured the problem, moral damages for the inconvenience and stress suffered, or even termination of the lease if the dwelling has become uninhabitable.

The TAL can also award punitive damages if the landlord showed gross negligence or bad faith. The amounts awarded vary with the severity and duration of the problem, but rent reductions of 20% to 50% have been granted in cases of severe mould, on top of moral damages that can reach several thousand dollars.

To act now, use our tool dedicated to mould and unfit-housing problems to assess your situation. If you're ready to send a demand letter, our demand letter generator lets you create and send a professional document in just a few minutes.