The owner of an immovable property in Quebec may be the king of his castle but what he does to or with his property is limited, not only by zoning regulations, but also by the adverse consequences that legitimate activity may have on a neighbor. Neighbors are also the kings of their castles and competing rights may often conflict.
What are the legal principles that determine when a property owner may be liable for damages that he has caused to a neighbor? The leading court decision on this subject was rendered by the Supreme Court of Canada in St. Lawrence Cement Inc. v. Barrette.(1)
This decision clarified what was until then, a conflicting and controversial area of the law. The Supreme Court decided that there are actually two (2) complementary regimes of legal liability that are applicable.
The first requires a degree of fault or negligence on the part of the offending property owner, which is consistent with the general theory of liability applicable to most civil claims. Under this regime, the victim must prove the existence of a fault, i.e. the breach of an objective standard of conduct, damages and a direct causal link between the two.
In the St. Lawrence Cement case, the evidence established that the cement plant operated by St. Lawrence Cement ("SLC") caused substantial dust, odor and noise that disturbed the owners of other properties located in the vicinity of the SLC plant. The evidence also established that SLC had implemented reasonable measures to minimize the disturbance and consequently, was not negligent or at fault and was merely exercising its right of ownership in a reasonable manner by operating its business on the property that it owned.
The second regime of liability which is specifically applicable to property owners, does not rely on impeachable conduct as a basis for a successful claim. It is a no fault liability regime based upon Article 976, Civil Code of Quebec, which reads as follows:
Neighbors shall suffer the normal neighborhood annoyances that are not beyond the limit of tolerance they owe each other, according to the nature or location of their land or local custom.
This regime ignores the conduct of the property owner and instead, focuses on the annoyance suffered by the victim that, when deemed to be excessive, triggers the legal liability of the offending property owner.
In the SLC case, the Court concluded that SLC had not committed any civil fault; had fulfilled its obligation to implement the best available means to eliminate dust and smoke; and had taken reasonable precautions to ensure that its equipment was in good working order.
The Court, however, concluded that neighbors of the plant suffered excessive annoyance that was beyond the limit of tolerance that neighbors generally owe to each other, and SLC was condemned to compensate them accordingly.
(1) St. Lawrence Cement Inc. v. Barrette,  3 S.C.R. 392, 2008 SCC 64 (CanLII)