Assigning Responsibility for Remediating Mould

August 22, 2019 | Caleb Edwards

Repair and maintenance obligations are split between unit owners and the condominium corporation. The Condominium Act requires the corporation to maintain and repair the common elements. In general, unit owners are responsible for repairs to their own units and for damage they cause to the common elements. What happens, however, when you cannot be sure where the damage started?  The discovery of mould in a unit is a situation that often presents these problems.

The source and cause of mould can be difficult to pin down. The environment, the building design, and the unit owner’s behaviour all play roles in the growth and spread of mould. Mould develops over a period of many years. These different factors make attributing responsibility for the damage particularly difficult, which often leads to litigation.

If you are faced with a mould situation and worried about litigation, the following factors will be useful to determine who is responsible:

1. Expert Inspections

Because of the complexity in determining the cause of mould, courts will rely on the opinions of qualitied and experienced professionals. An in-depth opinion by an experienced expert is the strongest tool in attributing blame for mould.

2. Reasonable Behaviour

In assigning responsibility, courts will look at the reasonableness of an occupant’s behaviour. While the behaviour may be partially responsible for mould, courts will not require extreme, costly, or other exceptional measures that would impinge upon normal daily activities. For instance, while keeping windows open might reduce moisture levels, occupants cannot reasonably be expected to do so during harsh Canadian winters.

3. Presence of Mould in Other Units

Another major factor will be whether mould is present in other units. The presence of mould in similar condominium units and in similar locations suggests that the cause is not attributable to unreasonable lifestyle choices.

Brasseur v York

In Brasseur v York, 2019 ONSC 4043, a unit owner sued the condominium corporation for its conduct in remedying mould in their condominium. The unit owner argued that the mould was caused by issues relating to the common elements. The corporation said it was not responsible because it was the owner’s lifestyle choices that caused the mould.

The court considered two expert opinions from the owner and the condominium corporation. Faced with these conflicting opinions, the court preferred the owner’s evidence as it was an in-depth inspection without factual errors underlying the opinion.

The court rejected the suggestion that the owner’s lifestyle choices were to blame. While the owners could have done more to prevent the mould, those steps were not reasonable.

The unit owner led evidence that other unit owners had experienced the same mould.  The court found it implausible to suggest that the other occupants had caused the mould by behaving in the same fashion. The more plausible explanation was that of the unit owner’s expert, who attributed mould to problems in the building design and construction.

Lesson from Brasseur: What to do if you find mould in your building?

(i) Remediate When Mould is a Danger

Condominiums should undertake remediation of the mould on a without prejudice basis if:

  • the species of mould is a danger to health;
  • the mould is at unacceptably high levels; and
  • that information is verified by an expert.

Otherwise, the condominium corporation may be found in violation of their duties under the Condominium Act.

(ii) Graduated and Cost-Conscious Remediation

In carrying out remediation, corporations do not have to always go with the most comprehensive and expensive option for remediation. Mould and its re-occurrence is a complex issue. According to the court in Brasseur, condominium corporations are entitled to take a graduated and cost-conscious approach they hope will remedy the problem. Provided they do so without an unreasonable delay, corporations will not likely be liable for oppressive conduct.


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