Do I need a party wall agreement?
You need to serve notice under the Party Wall etc. Act 1996 if you are building on or at the boundary, cutting into a shared wall to insert beams, or excavating within 3m of a neighbour's foundations to a greater depth. On a Fulham terrace, almost every extension and loft conversion triggers it.
Three types of work trigger the Act. Work directly to a party wall — inserting a steel beam, removing a chimney breast, underpinning — requires two months' notice. Building on the line of junction at the boundary requires one month. Excavating within 3m of a neighbouring structure and deeper than its foundations, or within 6m at a certain angle, requires two months. Terraced houses in Fulham share walls on both sides, so most projects hit at least one.
If your neighbour consents in writing, no award is needed and the process ends there. If they dissent, or do not respond within 14 days, a dissent is deemed and surveyors must be appointed to produce a Party Wall Award. One agreed surveyor can act for both parties, which is cheaper; otherwise each side appoints their own and the building owner pays both. Budget £1,500 to £3,000 per adjoining owner.
The Act is civil law, so the council will not enforce it — but your neighbour can seek an injunction stopping work, which is far more disruptive than the process itself. Serve early: notice periods run alongside design and planning, so if they are started when drawings begin they cost nothing in programme. Leaving them until the week before the builders arrive costs two months.
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