Who pays the Third Surveyor?

Per Act, Third Surveyor decides apportionment based on conduct + outcome. Typically party 'at fault' or 'unreasonable' pays 70–100% of Third Surveyor's fees. Loser's own surveyor's fees also usually borne by loser. Encourages settlement at two-surveyor stage.

Can I refuse a Third Surveyor my surveyor proposes?

Owner has no direct say in Third Surveyor identity — it's the two appointed surveyors' joint decision. Owner can challenge a Third Surveyor's impartiality post-appointment if conflict of interest evident, but the surveyors' choice is generally final + appointed at outset.

What if the two surveyors can't agree on a Third Surveyor?

Act Section 10(1)(b): either surveyor (or Owner) can apply to Appointing Officer (designated at local council, usually Building Control surveyor) who selects Third Surveyor. Rare in practice — surveyors usually agree among the known pool of senior practitioners.

Third Surveyor Party Wall London 2026 | Builderr

What Is a Third Surveyor Under the Party Wall Act in London?

Third Surveyor under the Party Wall etc Act 1996 is a jointly-appointed independent surveyor selected at the start by the two appointed party wall surveyors (one Builder Owner's surveyor + one Adjoining Owner's surveyor). The Third Surveyor resolves disputes when the two appointed surveyors disagree on award terms. Acts impartially. Fee £350–£1,250/hour; party at fault typically pays. Used in <5% of party wall awards. Identity agreed by both surveyors at appointment.

Role + appointment

Party Wall etc Act 1996 Section 10: when notice served + Adjoining Owner dissents, each side appoints a party wall surveyor. The two surveyors immediately + jointly appoint a Third Surveyor (Section 10(1)(b)) — not used unless dispute escalates, but identified up-front. Third Surveyor must be impartial — no connection to either party + no involvement in scheme. Typical Third Surveyors: senior + experienced party wall practitioners with FPWS (Faculty of Party Wall Surveyors) or RICS Diploma in Party Wall Practice + 10+ years experience. Pool of established London Third Surveyors well-known among practitioners (Henry Burton FRICS, John Anstey FRICS historic exemplars; current pool ~30 senior practitioners across London).

When invoked

If two appointed surveyors disagree on any aspect of award: scope of works covered, schedule of condition extent, security for expenses amount, methodology, monitoring requirements, fees apportionment. Either surveyor (or either Owner) refers matter to Third Surveyor. Third Surveyor reviews papers + may convene meeting + makes binding decision on disputed point. Decision can be in form of award. Used in <5% of party wall matters — most disputes resolve between two surveyors. Third Surveyor's decision appealable to County Court within 14 days (rare; high cost; high bar for overturn). Third Surveyor can also be invoked for ex-parte award when one surveyor fails to act + other proceeds alone (Section 10(7)).

Cost + practicalities

Third Surveyor fees: £350–£1,250/hour typical (top-tier London practitioner) — significantly higher than appointed surveyors (£185–£385/hour typical). Hours per dispute: 5–30 hours typical depending on complexity. Total cost £1,750–£37,500 per referral. Cost allocation: under Act, the party 'at fault' (whose position was unreasonable) typically pays — Third Surveyor decides. Strategic implication: invoking Third Surveyor is high-stakes — losing party pays significant fees + may also be liable for adversary's surveyor's additional time. Practitioners use Third Surveyor sparingly — usually attempted negotiation first. Builderr practice: pre-appoint reputable Third Surveyor at award stage; agree fee scale up-front; never used in 95%+ of party wall matters.