When the Building Owner and Adjoining Owner appoint separate surveyors but those surveyors cannot resolve a point, the third surveyor provides the tie-break mechanism under Section 10 of the Party Wall etc. Act 1996. Here’s how it works in practice.
1) Selection must happen “forthwith” (s.10(1)(b))
As soon as the two surveyors are appointed, they should immediately select a third surveyor—before any disagreement arises. If the owners have appointed a single Agreed Surveyor, no third surveyor is needed.
Typical selection process
- The Building Owner’s surveyor suggests 3 names by email.
- The Adjoining Owner’s surveyor chooses one, asks for more names, or proposes their own.
- Continue until agreement is reached.
If no agreement is possible, proceed to s.10(8).
2) If the two can’t agree, the appointing officer steps in (s.10(8))
Failure to agree on a third surveyor triggers a referral to the appointing officer (usually the head of Building Control for the local authority). If the local authority is itself a party, the Secretary of State makes the appointment.
In practice, third surveyor panels are small in many areas; suggested names are often familiar senior practitioners.
3) If the chosen third surveyor won’t act (s.10(9))
If the selected third surveyor refuses or neglects to act, the selection process starts again. This happens occasionally—especially where a senior surveyor has retired or is unavailable.
4) What the third surveyor actually does (s.10(11))
The third surveyor “determines the disputed matters” referred by either owner or either appointed surveyor and confirms the decision in an award. The usual flow is:
- Each appointed surveyor makes a written submission (with evidence).
- The third surveyor invites one round of comments on the other side’s submission.
- The third surveyor issues an award on the referred points.
Most referrals concern:
- Fees (often challenges to the reasonableness of the Adjoining Owner’s surveyor’s time/charges), or
- Damage responsibility/quantum and making-good terms.
Owners can, in theory, refer matters directly to the third surveyor, but in practice it’s rare and typically only where an owner disputes their own surveyor on an issue not yet decided in an award (if it were already decided, the route would be appeal).
5) Service of the third surveyor’s award & fees (s.10(15))
The award must be served on the owners. Service is usually handled via the appointed surveyors. The third surveyor will also decide who pays their fee and any related costs of the appointed surveyors tied to the referral.
Unlike the two appointed surveyors, third surveyors often require payment before service of their award. A common approach is to ask both owners to pay 50% up-front, with the award then apportioning liability between them.
Good practice & practical tips
- Select early, document clearly: Name the third surveyor at the outset and record contact details in correspondence/Award.
- Refer only what’s necessary: Keep the referral tight; bundle issues that are genuinely linked, and provide clear evidence.
- Fee disputes: Provide a reasoned, proportionate fee analysis (scope, complexity, benchmark hours/rates), not just a blanket objection.
Quick checklist for appointed surveyors
- Third surveyor selected forthwith and recorded.
- Disputed issues clearly defined; jurisdiction checked.
- Evidence bundle concise and relevant (drawings, method statements, photos, costings, correspondence).
- One measured submission each; one comment opportunity only.
- Fee/security arrangements agreed with the third surveyor pre-service.
- Award served on owners and cost apportionment implemented.
Want a measured second opinion before you refer?
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