Who owns a boundary wall in Ireland?

Unlike some other jurisdictions, Irish law has no general presumption (such as a fixed 'T-mark' rule) that automatically tells you who owns a particular boundary wall. Ownership is a question of title, established primarily by what the deeds say. Some older conveyances expressly state that a wall or fence belongs to, and must be maintained by, a particular owner, in which case that clause is decisive.

Where the deeds are silent, which is common, ownership is inferred from the evidence available: which party built and has maintained the wall, which side any piers, coping stones or footing project towards, and long-standing conduct of the neighbouring owners. None of these are conclusive on their own, and in practice many boundary walls have unclear or shared ownership, particularly where they have stood for generations.

A wall can also be a 'party structure' effectively shared by both properties, especially where it forms part of both buildings (such as a shared gable) or where both owners have historically maintained it. Because ownership affects who can alter, repair or attach things to the wall, it is worth checking the deeds and, if in doubt, taking advice before carrying out works.