Can we use one agreed party wall surveyor?
The short answer
Yes, if both owners agree - and for most straightforward domestic projects you should. An agreed surveyor acts impartially for both sides under the Act, produces the same legally binding award, and costs roughly half of the two-surveyor route: typically £700 to £1,200 against £1,500 to £3,000.
Impartial by law, not hired muscle
The crucial point neighbours misunderstand: a party wall surveyor's duty is to the Act, not to whoever appointed them. An agreed surveyor isn't "the builder's man" - they're a statutory referee producing an award that protects both properties. The same is true of separately appointed surveyors, which is why two of them usually reach the same award one would have - at twice the price, normally all paid by the building owner.
| One agreed surveyor | One surveyor each | |
|---|---|---|
| Typical cost | £700 - £1,200 | £1,500 - £3,000 |
| Who pays | Building owner | Building owner, both bills |
| Speed | Faster - one diary, one draft | Slower - two diaries, correspondence |
| Protection | Full award, schedule of condition | The same |
| Best for | Straightforward lofts and extensions | Basements, strained relations, complex works |
When separate surveyors are genuinely wiser
The agreed route depends on both owners trusting one professional. Go separate when the works are complex or high-risk next door (basements are the classic), when the relationship is already strained, or when the adjoining owner simply feels better represented - which the Act entitles them to, at the building owner's reasonable expense. An anxious neighbour forced toward an agreed surveyor often costs more in friction than the second fee would have.
Ready to appoint?
Verified party wall surveyors quote for agreed-surveyor awards with fixed fees - one enquiry, free, no obligation.
Get a few quotesHow the appointment works
The agreed surveyor is appointed in writing by both owners once a notice has been dissented from (the notice process comes first). They inspect and record the adjoining property's condition, settle how and when the notifiable work happens, and serve the award. Either owner keeps the right to refer disagreements about the award to the third surveyor mechanism - the Act's built-in appeal valve - though on domestic jobs it's rarely needed.
Costs for your scenario - works type, neighbours, arrangement - are in the party wall cost calculator, and the wider fee picture is in the award cost guide.
Common questions
Who chooses the agreed surveyor?
Either side can propose; both must appoint in writing. In practice the building owner usually suggests a local specialist and the neighbour agrees - or counter-proposes. Any RICS or party-wall specialist unconnected to the project works.
Can my builder or architect be the agreed surveyor?
No one already involved in the project should act - impartiality is the whole point, and the Act bars the building owner themselves. Appoint an independent surveyor.
What if we start agreed and fall out?
The award still binds. Disputes about it go to the third surveyor mechanism. An agreed surveyor can't be sacked mid-process by one side - another reason the appointment paperwork names them clearly.
Does the agreed surveyor route weaken my protection as the neighbour?
No - same schedule of condition, same binding award, same access to the third surveyor if you think the award is wrong. You give up an advocate, not protection.
Sources and further reading