A party wall is the shared wall, between a terrace, semi-detached or detached house if the distance between them is less than 3 meters.
It also includes garden walls built over a boundary and excavations close to a neighbour’s property within three or six meters, depending on the depth of the new foundations.
In the home, Party Wall Agreements are most commonly needed for building works that involve loft conversions, extensions, wall removal if you need to insert steel / RSJ on the shared wall, the insertion of damp proof and the digging of new foundations.
Before party wall building works can start, you will need a written party wall agreement from all affected neighbours. Usually surveyor has to be appointed to prepare this for you.
You should take dated photos of the party wall and ideally have agreed written notes of any cracks, with copies for you and your neighbours.This is very important to minimise the risk of disputes later. This should be done before the work commence.