3.14 Key Legal Principles

While dispute resolution is a less formal legal proceeding than court, arbitrators and judges still consider many of the same legal principles when making decisions. This section provides a brief overview of five principles that commonly show up in dispute resolution decisions. If you think that a legal principle applies to your situation, bring it to the attention of the arbitrator; do not assume that they will automatically consider it.


Res Judicata

The principle of “res judicata” prevents a party from pursuing a claim that has already been decided. For example, if an arbitrator rules that your dispute does not fall under the Residential Tenancy Act, you are not allowed to apply for a second hearing to re-argue your case. If you do, the new arbitrator will look at the previous arbitrator’s decision and dismiss your application because the issue of jurisdiction is res judicata.


Contra Proferentem

The principle of “contra proferentem” says that when a term in a contract is ambiguous, it should be interpreted against the interests of the party who drafted it. For example, if a tenancy agreement broadly states that “the tenant must pay for utilities”, the landlord may struggle to argue that the tenant owes money for any specific utility, such as heat or electricity, since the term is so ambiguous.



The principle of “waiver” relates to the voluntary surrender of known contractual rights. According to RTB Policy Guideline 11, there are two types of waiver:

  1. Express Waiver. The tenant and landlord clearly and unequivocally agree to waive a right. For example, they sign and date an agreement to cancel an eviction notice and reinstate the tenancy.
  2. Implied Waiver. The tenant or landlord waives a right through their actions or behaviour. For example, if a landlord accepts rent for the period after the effective date of an eviction notice, they may have reinstated the tenancy and canceled the notice. (One exception to this rule is when a landlord accepts rent for “use and occupancy only”. In this scenario, the landlord has most likely protected themselves against reinstating the tenancy.)



The principle of “estoppel” prevents a party from arguing something or asserting a right that contradicts their previous behaviour. It is meant to prevent someone from being unjustly wronged by the inconsistencies of another person’s words or actions. For example, if a tenant regularly e-transfers rent a day or two late over an extended period, and the landlord never communicates any issues with this arrangement, then the landlord may not have grounds to suddenly evict the tenant for repeated late payment of rent. In other words, if there has been an established trend of the landlord acquiescing to late payments of rent, they may be estopped from issuing a One Month Notice for Cause for repeated late payment of rent. 


Statutory Interpretation

The principle of “statutory interpretation” refers to how courts read, interpret, and apply legislation. More specifically, there is a “modern principle” of statutory interpretation that the Supreme Court of Canada, in Rizzo & Rizzo Shoes Ltd., identified as its preferred approach:

“Today there is only one principle or approach, namely, the words of an Act are to be read in their entire context, in their grammatical and ordinary sense harmoniously with the scheme of the Act, the object of the Act, and the intention of Parliament.”

Furthermore, section 8 of the Interpretation Act says that:

“Every enactment must be construed as being remedial, and must be given such fair, large and liberal construction and interpretation as best ensures the attainment of its objects.” 

In a residential tenancy law context, case law such as Berry and Kloet has established that the RTA was created to confer a benefit upon tenants that would not otherwise exist. This means that if you feel there is ambiguity in the language of the RTA, you can put forward a statutory interpretation argument that the arbitrator should interpret that ambiguity in favour of the tenant.