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Glossary of party wall terms

Plain-English definitions of the terms used throughout the Party Wall etc. Act 1996 and our knowledge base — so the language never gets in the way of understanding your position.

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Plain English

32 key terms
UK party wall law
By Karmjit Grewal

A B D E F L M N P R S T U

Adjoining owner: An owner of land, a building or part of a building next to the building owner's property who may be affected by notifiable works. There can be more than one adjoining owner for a single project.
Agreed surveyor: A single surveyor appointed jointly by both owners to resolve the dispute impartially under the Act. They do not act as either owner's agent and using one usually keeps costs predictable.
Award (party wall award): The formal document, settled by the surveyor(s), that authorises the notifiable work and sets out how it must be carried out, the rights and protections of each owner, and how costs are dealt with. Also called the party wall agreement.
BRE Digest 251: A Building Research Establishment classification used to categorise the scale of cracking and damage to low-rise buildings, from negligible (aesthetic) through to severe (structural).
Building owner: The owner of land who is carrying out, or proposing to carry out, work to which the Act applies. The building owner is usually responsible for the reasonable surveyor's fees arising from their works.
Deemed dissent: Where an adjoining owner does not consent to a notice within 14 days, a dispute is deemed to have arisen and the surveyor procedure under section 10 is triggered.
Deemed service: The point at which a notice or document is treated in law as having been served — for example, a set number of working days after posting by first-class post — even if actual receipt is disputed.
Dissent: Where an adjoining owner does not agree to the proposed works as notified. Dissent (actual or deemed) starts the surveyor process; it is not an objection that stops lawful work.
Ex parte award: An award made by the building owner's surveyor alone where the adjoining owner's appointed surveyor refuses or neglects to act, following the procedures in section 10.
Functus officio: A surveyor who has completed the task for which they were appointed and so no longer has authority to act, unless and until a fresh matter or dispute arises.
Line of junction: The boundary line between the lands of two owners. Special rules and notices apply where a building owner wishes to build a wall up to, on or astride the line of junction.
Line of junction notice: A notice served where a building owner intends to build a new wall up to or across the boundary between the two properties (section 1 of the Act).
Making good: Repairing damage caused to the adjoining property by the notifiable works, or (where agreed) making a payment in lieu of carrying out the repair.
Making use / enclosure costs: A contribution the adjoining owner may pay where they later make use of work previously carried out by the building owner (for example, by building onto a party wall). Often dealt with under section 11(11).
Notice: The formal written notification a building owner must serve on adjoining owners before starting notifiable work. Different works require different notice periods (commonly one or two months).
Notifiable work: Work covered by the Act that requires notice to be served — broadly, work to a party structure, building a wall at the boundary, and certain excavations near a neighbouring building.
Party fence wall: A wall standing astride the boundary that is not part of a building — for example, a masonry garden wall — and is used to separate adjoining lands.
Party structure: A wall or floor partition (or other structure) separating buildings or parts of buildings approached by separate staircases or entrances — wider than a party wall and common in flats.
Party structure notice: A notice served where the building owner intends to carry out work to an existing party wall or party structure (section 2 of the Act), generally requiring two months' notice.
Party wall: A wall that stands on the lands of two owners and forms part of a building, or a wall on one owner's land used by two owners to separate their buildings.
Party Wall etc. Act 1996: The Act of Parliament that governs work to party walls and structures, building at the boundary, and excavation near neighbouring buildings, providing a framework to prevent and resolve disputes.
Post-work inspection: An inspection carried out after the works to compare the property against the schedule of condition and identify any damage attributable to the works.
Pyramus & Thisbe Club: A long-established body of party wall practitioners that publishes commentary and guidance notes on party wall practice. Its guidance is influential but is not law.
RICS: The Royal Institution of Chartered Surveyors, which publishes professional standards and guidance for surveyors. Its guidance reflects good practice but does not override the Act.
Schedule of condition: A written and/or photographic record of the condition of the adjoining property before works begin, used to assess whether the works have caused any damage.
Section 10(4): The provision allowing a surveyor to be appointed on behalf of a party who refuses or neglects to appoint one, so the dispute-resolution process can continue.
Section 6 notice: A notice required where excavation (and, in some cases, construction) is proposed within three metres (or six metres in defined circumstances) of a neighbouring building or structure.
Security for expenses: A sum the adjoining owner may, in appropriate cases, require the building owner to set aside to cover the cost of making good if works are started and not completed.
Special foundations: Foundations using reinforcement (such as reinforced concrete) to distribute load. They generally require the adjoining owner's express written consent and cannot be placed on the adjoining land without it.
Surveyor: A person appointed under the Act to determine the dispute. The role is impartial and statutory — the surveyor is not an advocate for the owner who appointed them.
Third surveyor: A surveyor selected by the two appointed surveyors at the outset, who can be called upon to determine a matter if the two surveyors cannot agree.
Underpinning: Strengthening or deepening existing foundations, often near or beneath a party wall or neighbouring structure, which is typically notifiable under the Act.

Disclaimer. These definitions are a general, plain-English guide only and are not legal advice. The precise meaning of terms under the Party Wall etc. Act 1996 depends on the statute, case law and the facts of each matter. Always seek advice from a suitably qualified professional.

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