Mould smell in a new Ottawa rental, should I worry?

A mould smell in a rental is worth taking seriously, even if you cannot see anything yet. A musty smell is a reason to look for moisture, and finding the source is the first step.

Health Canada classifies mould by what you can see. A small area is one to three patches, each less than one square metre. A medium area is more than three patches, or patches greater than one square metre but less than three square metres. An extensive area is a single patch larger than three square metres. Health Canada says you can generally clean small and medium sized areas yourself, and recommends getting professional help with extensive mould growth.

In a rental, the practical question is who is responsible for fixing it. That sits in landlord-tenant law, which this site does not cover, so check the rules that apply to tenants or ask a legal clinic. What this site can tell you is that we found no Ontario statute or regulation that licenses mould remediators or sets indoor mould limits.

For any mould job, the moisture source comes first. Cleaning mould without stopping the water that feeds it means it comes back. Once the moisture is dealt with, a reasonable post-remediation check looks at three things: the written scope of work was completed, the moisture source was repaired, and no visible mould remains.

If the building is older and any remediation involves cutting or removing drywall, plaster, ceiling texture or flooring, raise the asbestos question before work starts: Health Canada advises hiring a professional to test before renovating.

Local contractors who handle mould assessment, listed in the Ottawa Construction Network directory, reply by email to requests from the form on this page.

Before anyone starts work, ask the contractor to give you the written scope of what they plan to do and how they will confirm the job is complete.