Party walls: notices, awards, and your neighbours

On terraced and semi-detached London streets, almost nothing structural happens without touching a shared wall or digging near a neighbour's foundations. The Party Wall etc. Act 1996 is the legal machinery for that fact: a national framework that gives you the right to do the work — and your neighbour the right to have it done carefully, documented, and at your expense if anything goes wrong. It is not planning permission, it is not building regulations, and it runs on its own clock.

Your Siteline dossier flags "party wall risk" against project types for exactly this reason: a rear extension on a mid-terrace typically engages the Act on both flanks, a loft conversion lands steel beams in shared walls, and a basement is the heaviest party wall procedure in domestic construction. This page explains what the Act covers, what the process really costs, and the one mistake that turns neighbours into litigants.

The three notices, and their clocks

Section 2 is the workhorse: it covers cutting into a party wall to insert beams or flashings, raising it, underpinning it, removing chimney breasts from it, and most structural surgery a loft or extension involves. Section 6 catches excavation within 3 metres of a neighbouring structure that goes deeper than their foundations — and within 6 metres where the dig cuts a 45-degree line drawn down from their foundations, which is why basements routinely notify properties two doors away.

Consent, dissent, and what an award is

Your neighbour has 14 days to respond. If they consent in writing, the Act steps back — though a schedule of condition (photographic record of their property) is still strongly advisable, because it is the evidence that protects both of you later. If they dissent, or simply don't reply, a dispute exists in law and surveyors must be appointed: either one "agreed surveyor" acting impartially for both sides, or one each plus a third surveyor selected in reserve to resolve deadlocks.

The surveyors produce a party wall award — a legally binding document recording the condition of the neighbouring property, the permitted works and method, working hours, access arrangements, protections, and who pays for what. The award is not a hostile act; it is the mechanism that lets your project proceed with your neighbour's structure legally protected. Either party can appeal an award to the county court within 14 days, but in practice awards close disputes rather than open them.

What it costs, and who pays

The building owner — the one doing the works — pays the reasonable fees of both sides' surveyors, and pays for making good any damage the works cause. The Act also lets a neighbour ask for security for expenses on riskier works (basements especially): money set aside up front so an abandoned excavation doesn't become their problem. These ranges are market figures from our casework; complex structures and prime-central buildings run higher.

The classic mistake: starting without serving

Works begun without notice carry three consequences. First, your neighbour can seek an injunction stopping the job mid-build — and courts grant them. Second, you lose the Act's protections: rights of access, the dispute mechanism, and the presumption of process all run against you, and any damage dispute lands in common-law nuisance and negligence instead, with you on the back foot. Third, there is no retrospective notice — the Act cannot be re-engaged for works already done, so the dispute can only be settled by negotiation or litigation. Two months of notice is cheap; an injunction with scaffolding up is not.

If you're the neighbour receiving a notice

Don't ignore it — silence counts as dissent after 14 days and the process starts anyway, just slower. Read what's proposed; if the works are modest and the notice is professional, consenting with a schedule of condition keeps things simple. If steels, underpinning or excavation are involved, appointing a surveyor (at the building owner's cost) is reasonable and normal. What you cannot do is veto lawful works — the Act exists precisely to balance their right to build against your right to protection.

How this fits your project

Party wall procedure runs in parallel with planning, building regulations and — for flats — your licence to alter. None waits for the others, and the programme killers are the sequential surprises: discovering the notice requirement after the builder is booked. Serve early, budget the surveyor fees from the start, and treat your neighbour's schedule of condition as project insurance. Party wall surveying is core work for Hampstead Chartered Surveyors, the RICS-regulated practice Siteline routes complex enquiries to — acting as building owner's, adjoining owner's and agreed surveyor across North and Central London.