It can look confusing at first: you appoint a surveyor, your neighbour appoints a surveyor—and then you hear there’s a third surveyor as well. In most party wall matters, there are not three surveyors actively working day-to-day. The “third surveyor” is best understood as a statutory safety valve: an independent decision-maker selected at the outset only in case the two appointed surveyors cannot agree.
This article explains why the third surveyor exists, when they are required, and how they are used in practice.
The legal reason: the Act requires a “third surveyor” in two-surveyor cases
When a dispute arises (or is deemed to arise) under the Party Wall etc. Act 1996, there are two routes:
- Agreed Surveyor — both owners concur in appointing one surveyor; or
- Two surveyors — each owner appoints a surveyor, and those two surveyors must “forthwith select a third surveyor” (the Act refers to them collectively as “the three surveyors”).
The third surveyor is therefore not an optional extra. If the two-surveyor route is used, selecting a third surveyor at the outset is a statutory requirement.
What each surveyor is there to do
The two appointed surveyors
In a typical two-surveyor appointment:
- the building owner’s surveyor and the adjoining owner’s surveyor review the proposals, consider risk and safeguards, and agree the terms of the Party Wall Award; and
- they will usually arrange a Schedule of Condition of the adjoining property (where access is available), so there is a clear record of condition before works commence.
Although each surveyor is appointed by an owner, the role is not “advocacy”. RICS emphasises that a party wall surveyor’s appointment is statutory, personal to the surveyor, and independent of instructions from the appointing party.
The third surveyor (the “referee”)
The third surveyor is selected so that there is always a neutral mechanism to resolve deadlock. The Act specifically provides that either owner or either of the two surveyors may call upon the third surveyor to determine the disputed matters, and the third surveyor “shall make the necessary award.”
In other words, the third surveyor is there to ensure the process cannot be stalled indefinitely by disagreement.
Why the third surveyor is selected at the start (even if they may never be used)
Selecting the third surveyor “forthwith” creates certainty and prevents delay later. If a disagreement arises mid-process—perhaps at a critical point in the project—you do not want to be debating who the independent decision-maker should be. The third surveyor is chosen early so the matter can be referred promptly if needed.
The Government’s explanatory guidance describes the third surveyor as someone who is called in only if the two appointed surveyors cannot agree, or if either owner or either surveyor calls upon them.
When the third surveyor actually becomes involved
Most party wall matters conclude with the two appointed surveyors agreeing an Award, and the third surveyor remains in the background. Where involvement does happen, it is usually because there is a genuine impasse on one or more points, such as:
- technical safeguards (sequencing, temporary support, protection measures)
- access arrangements and practical working restrictions
- the scope of notifiable works and what documents should be relied upon
- alleged damage and the appropriate remedy
- fees and costs (a common referral point in practice)
The Act also provides that the reasonable costs of making or obtaining an award and related inspections are payable by such party or parties as the surveyor(s) determine, which is why costs can become a matter for determination.
What if the two surveyors do not select a third surveyor?
The Act anticipates that possibility. If one surveyor refuses or neglects to select a third surveyor within the statutory framework, an appointing officer (or in certain circumstances the Secretary of State) can select a third surveyor on application—so the process can still progress.
Why the system is designed this way
The Party Wall Act is unusual because it places dispute resolution largely in the hands of surveyors rather than requiring the parties to go straight to court. The third surveyor forms part of that design: a built-in escalation route that keeps matters moving and provides a structured, impartial way to resolve deadlock.
Need advice on whether the two-surveyor route is right for your project?
Email mail@howorth.uk or call 07794 400 212 with a brief summary of the works and where you are in the process (notice served / dissent / surveyors appointed). We can explain the most proportionate route and what to expect at each stage.