The Party Wall etc. Act 1996 defines a party wall in Section 20. There are two main types of party walls, described in subsections (a) and (b).
Type A Party Wall — Walls Straddling the Boundary
Section 20(a) defines a party wall as:
“a wall which forms part of a building and stands on the lands of different owners to a greater extent than the projection of any artificially formed support on which the wall rests.”
In simpler terms:
- You look only at the position of the wall itself, not the foundations or any artificial supports beneath it.
- If the wall straddles the boundary line between two properties (even if not equally balanced on each side), it is a party wall.
- The wall must be part of a building — that is, at least one side of the wall encloses some part of a property, such as an external wall of a kitchen or living room.
Type B Party Wall — Walls Built Up to the Boundary on One Owner’s Land
Section 20(b) covers a different situation:
- This type of wall is built entirely on one owner’s land, right up to the boundary line.
- If the neighbour then builds an extension that attaches to and uses that wall as a dividing wall between their building and yours, the part of the wall they use becomes a type B party wall.
- The neighbour must have your permission to do this; otherwise, it is considered trespass. Many property owners are unaware that attaching a building to a boundary wall without permission is unlawful.
- Whether the wall is built right on the boundary line or set back from it, if the neighbour attaches to your wall, it is trespass.
Practical Example
Imagine you have a 4-metre-long, 3-metre-high wall built on your land against the boundary. Your neighbour builds a 3-metre-long, 3-metre-high extension against your wall, with or without permission. Only the portion of the wall that the neighbour has enclosed becomes a type B party wall. The remaining 1 metre that the neighbour did not use remains solely your wall.
Long-Term Use and Easements
- Over time, if the neighbour uses your wall as a party wall continuously for 20 years, they may acquire a legal easement allowing them to continue this use.
- Additionally, you lose the right to sue for removal of the trespassing structure after 12 years due to the statute of limitations.
- This is how many type B party walls come into existence — often without the original owner realising.
If you are unsure whether your wall is a party wall or whether your neighbour has rights over it, consulting a qualified party wall surveyor is strongly advised. Understanding the exact status of your walls helps avoid disputes and ensures compliance with the Party Wall etc. Act 1996.
FAQS
Q1. What is a party wall under the Party Wall Act?
A party wall is a wall that stands on land belonging to two owners and forms part of a building or separates buildings owned by different people.
Q2. Are garden walls considered party walls?
Yes, a garden wall can be a party wall if it stands astride the boundary and is not part of a building, as defined by the Act.
Q3. Are floors and ceilings party walls?
Floors and ceilings separating flats are classified as party structures under the Act and are treated in a similar way to party walls.
Q4. What is not considered a party wall?
Walls entirely on one owner’s land and not used by the neighbouring property are not considered party walls under the Act.
Q5. Why is it important to know if a wall is a party wall?
Knowing whether a wall is a party wall determines whether the Party Wall Act applies and whether formal notice and surveyor procedures are required.