The Party Wall Act doesn't just cover works to a Party Wall (a wall separating two properties or built astride a boundary), it applies to various building works on or close to a boundary. It sets down the rights & duties of owners undertaking such works and provides protection to the adjoining owners.
If a dispute arises between a person doing work and a neighbour a Party Wall Surveyor (or two Surveyors) must make a Party Wall Award to resolve the dispute. The surveyor's duty is to examine the proposed works and ensure that they are properly designed and are executed in a manner which is not likely to cause damage to adjoining buildings or property. A detailed record of the condition of the adjoining property is normally made so that if damage is caused it can be identified and then made good.