A party wall is a shared wall that stands on the boundary between two properties and is jointly owned by both adjoining owners. Both parties may use the wall and share responsibility for its maintenance.
How a party wall works
A party wall separates two buildings and sits exactly on the boundary line. Legally the wall is joint property, which means:
- Both owners may use the wall, for instance to rest beams on it.
- Costs for maintenance and repair are, in principle, shared.
- Neither owner may demolish or overload the wall without the other’s consent.
These rules fall under neighbour law and, in many jurisdictions, are set out in dedicated party wall legislation.
Application
Party walls are common in:
- Terraced houses – where homes share a dividing wall.
- Semi-detached houses – with a central load-bearing wall.
- Continuous urban blocks – where buildings are built up to the boundary.
For alterations, extensions or demolition, it is crucial to know whether a wall is a party wall. Shared walls must also meet specific technical requirements for sound insulation and fire safety.
Related terms
- Load-bearing wall
- Boundary line
- Facade
- Cavity wall
- Foundation
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