What is the discoverability rule of limitations for a plaintiff to sue for damages arising out of a drainage issue affecting the foundation of a house?

... the discoverability rule of limitations...does not call for perfect certainty. It does not require discovery at all: it says something else will do instead. It suffices that "the material facts on which [the cause of action] is based... ought to have been discovered by the plaintiff by the exercise of reasonable diligence...: Central Trust v. Rafuse 1986 CanLII 29 (SCC), [1986] 2 S.C.R. 147, 224. If the plaintiff is told a fact by someone who is likely to know, surely that makes the fact known or discoverable, even if someone else disputes the fact. Very few people who sue have perfect certainty. Therefore, while the full extent of the cause of the injury or the full extent of the damages may not have been known to the Plaintiffs in 2004, they had sufficient knowledge of the cause of the injury: a drainage issue affecting the foundation. Position of the Plaintiffs