If you are planning an extension, a loft conversion or structural work near a shared wall, the first legal question is simple: do I need a party wall agreement? The answer depends on what you are building and how close it sits to your neighbour’s property — and getting it wrong can stop a project mid-build.
When do you need a party wall agreement?
The Party Wall etc. Act 1996 applies in three situations. First, work directly to a shared (party) wall — cutting in beams for a loft conversion, removing a chimney breast, raising or underpinning the wall. Second, building a new wall up to or astride the boundary line. Third, excavating within 3 metres of a neighbouring building (6 metres for deep foundations) where your dig goes deeper than their foundations.
If your project involves any of these, you must serve a party wall notice before work starts. An “agreement” — formally a party wall award — is only required if the neighbour dissents or does not respond to that notice.
When do I need a party wall agreement — and when don’t I?
You generally do not need one for internal redecoration, replastering, shallow garden walls wholly on your own land, or drilling to hang shelves on a party wall. Minor works that do not affect the structure fall outside the Act. If in doubt, the 3-metre rule is the trigger most homeowners miss: even a modest rear extension usually involves foundations within 3 metres of next door.
What happens if you skip it?
Without a valid notice and (where required) an award, a neighbour can seek an injunction that halts your build, and you lose the Act’s protections if damage is alleged. Retrospective agreements are slower and more expensive than doing it properly at the start.
What does it cost?
If the neighbour consents in writing, the notice can cost you nothing beyond the letter. If surveyors are appointed, budget from around £900 per appointed surveyor — our party wall surveyor cost guide breaks down the typical fees, and our party wall services page explains the process step by step.
Speak to a surveyor before it becomes a dispute
Kingston Surveyors arranges RICS party wall surveyors, building surveys and valuations across London and the surrounding counties. If you are unsure where you stand, call us on 0204 579 8270 or request a call back and we will organise the right professional for your situation — usually with an appointment within days.
