When the Act applies
Three triggers[Party Wall Act]: (1) work to a shared (party) wall; (2) excavation within 3m of a neighbouring building going below the neighbour's foundations; (3) excavation within 6m where the cut crosses a 45-degree line from the neighbour's foundation base. New foundations on a KDR almost always trigger (2) or (3) where neighbouring properties are close.
Notice periods
2 months notice for party-wall works; 1 month notice for excavation. The neighbour has 14 days to consent or dissent. Silence is treated as dissent under the Act, so the surveyor process triggers automatically. Issue notices early; the 2-month clock blocks foundation start.
Agreed surveyor vs dissenting
If the neighbour consents and both parties agree to use a single surveyor for the Award, total cost is typically £900-£2,400 per affected neighbour. If the neighbour dissents and appoints their own surveyor, each side instructs their own, costs run £2,500-£5,000 per side, and a third surveyor may be added at the parties' joint cost.
The Party Wall Award
The legal instrument the surveyor(s) produce. Contains: condition schedule (photos of neighbouring property pre-works), permitted hours and methods, indemnity arrangements, schedule of access, and procedure for damage claims. Award is enforceable; breach is a civil matter.