A party wall is a wall that stands on the land of two owners and separates their buildings, or a wall on one owner's land that is used by both to separate buildings. Ownership is usually shared along the line of the boundary, but the useful question is rarely who owns it. It is what each owner may do to it, and that is what the Act answers.
Party wall, party structure and party fence wall
A party wall separates buildings. A party structure is wider and includes floors and partitions between separately occupied parts of one building, which is why flats are caught. A party fence wall is a garden wall standing astride the boundary and not part of a building, and it is covered by the Act while a fence is not.
Who owns a party wall
Where the wall stands astride the boundary, each owner generally owns the half on their land, subject to the other's rights over the whole. Where it stands wholly on one owner's land but separates the buildings, the owner of the land owns it and the neighbour has rights of support. Neither position lets one owner do as they like.
Party wall repair responsibility
There is no automatic obligation on either owner to repair a party wall, which surprises people. What the Act provides is a right to carry out repair work, on notice, and a mechanism for apportioning cost where both owners benefit. A wall that is failing is usually dealt with by one owner serving a notice and the surveyors apportioning.
The semi detached party wall
In a pair of semi detached houses the dividing wall is the classic party wall, and almost anything structural done to it is notifiable: steels for a loft conversion, a chimney breast removal, underpinning, or a new opening. Terraces are the same with two walls instead of one.
Party fence wall rules, which are not the same as a party wall's
A party fence wall is a masonry wall that stands astride the boundary and separates the lands of two owners without being part of a building, which makes the garden wall between two houses the usual example. A timber fence is not one, whatever it is called, and neither is a wall built entirely on one owner's land, which is that owner's wall even if it sits right on the line. The act covers a party fence wall much as it covers a party structure: repairing, demolishing and rebuilding it, raising its height or underpinning it are notifiable works, and the neighbour has the same rights to consent, to dissent and to have a surveyor appointed. Two practical points follow. Costs of work to a party fence wall are shared according to use and benefit rather than automatically halved. And the wall's ownership does not change because one side has always maintained it, which is a common and expensive assumption.
Other questions people ask
Who owns a party wall between two houses?
Ownership usually follows the boundary, with each owner owning their side subject to the other's rights. The title plan and deeds are where to check, though for practical purposes the Act's rights matter more than ownership.
Can I attach things to a party wall?
Fixing a shelf on your own side is not notifiable. Cutting into the wall, bearing a beam on it, raising it or removing part of it is, and the difference is structural rather than a matter of degree.
Is a garden wall a party wall?
A wall standing astride the boundary and not forming part of a building is a party fence wall and is covered by the Act. A timber fence is not a wall and is not covered.
Is there a party wall detail or party wall diagram that shows which walls are caught?
No drawing decides it. The definitions in the Act do, and a wall is caught because of where it stands and what it separates rather than because it matches a picture. The government's own explanatory booklet on preventing and resolving party wall disputes illustrates the usual arrangements, which is useful for recognising your own case, and the sequence to follow is still the same: identify whether the wall stands astride the boundary or wholly on one side, then whether it separates buildings or only land, then read the definition.
What are the commonest party wall examples in an ordinary house?
The dividing wall between a pair of semi detached houses, and each dividing wall in a terrace, which is why steels for a loft conversion, a chimney breast removal, underpinning or a new opening are nearly always notifiable. The floor between two flats, because a party structure includes floors and partitions between separately occupied parts of one building. A garden wall standing astride the boundary, which is a party fence wall. And a wall wholly on one owner's land that the neighbour's building is built up against and uses for separation.