In the recent case of Kalantzis v Brown; Brown v Kalantzis; Kalantzis v Brown; Brown v Kalantzis (2026) NSWCA 17, the NSW Court of Appeal reinforced strict liability principles in construction-related property torts following a residential driveway collapse in Gosford. The defendants carried out excavation work near the boundary of a neighbouring property, removing soil that supported the land, which caused the adjoining driveway to fail and led the homeowners to sue for trespass and negligence. The plaintiffs successfully established both claims against the developer, builder, and individuals responsible for the excavation.
The Court confirmed that trespass does not require knowledge of the property boundary and extends to subsurface intrusion. Excavation that encroaches beneath an adjoining property, even if done mistakenly, constitutes intentional trespass. Importantly, liability for intentional trespass cannot be apportioned under the Civil Liability Act 2002 (NSW), meaning defendants may be jointly and severally liable for the full extent of damage.
In negligence, liability arose under section 177(2) of the Conveyancing Act 1919 (NSW), which prohibits removing support from neighbouring land. Despite geotechnical warnings highlighting a high risk of landslip, the defendants failed to implement recommended shoring and piling, thus materially contributing to the collapse. The Court emphasised that a defendant need not be the sole cause of damage; contributing materially is sufficient for liability.
This decision underscores critical considerations for developers and contractors: strict adherence to boundary limits is mandatory, geotechnical recommendations must be implemented, and defendants cannot rely on proportionate liability defenses to escape full responsibility. The ruling serves as a crucial reminder that even unintended or mistaken excavation can trigger significant legal and financial consequences.