The Alberta Court of Appeal held recently that the common law rule against apportionment and contribution in tort does not apply to breaches of contract.
Alberta legislation allows liability to be apportioned between tortfeasors, but there had been no guidance available for cases in which defendants are severally liable for a single loss caused by independent breaches of contract. In Petersen Pontiac Buick GMC (Alta.) Ltd. v. Campbell, 2013 ABCA 251, the case at bar involved plaintiffs who suffered the same loss, caused by a breach of contract by one party and a breach of a different contract and negligence by another.”
At trial, the judge held that the defendants’ liability was several, not joint; the causes of action were distinct and the defendants had not acted in furtherance of a common purpose. One defendant’s liability was held to be “secondary” to the other. That party appealed.
The Court of Appeal agreed that the liability of defendants was several because the causes of action were independent. However, it found that the trial judge had “misused” the concept of secondary liability.
In cases such as Blackwater v. Plint, 2005 SCC 58 (CanLII),  3 SCR 3, regarding Residential Schools, the Supreme Court of Canada has suggested that common law rules against apportioning liability for negligence, and against contribution between tortfeasors, are no longer in keeping with today’s concepts of justice and fairness.
These may no longer be absolute.
Negligence Act, RSO 1990, c N.1
Insurance Act, RSO 1990, c I.8
Mortimer v. Cameron, 1993 CanLII 568 (ON CA)
McCarthy Tetrault article