The Party Wall Act protects both neighbours during building work

When notice is required

Work that cuts into a party wall, builds astride a boundary, or involves excavation within a specified distance of a neighbouring building's foundations and below its foundation depth typically triggers the Act. This covers a lot of ordinary extension and loft conversion work in terraced and semi-detached properties, where a shared wall or close foundations are unavoidable.

It does not generally apply to detached houses with no shared structure and no excavation close enough to a neighbour's foundations, though boundary fences and some garden walls can still raise separate boundary law questions outside the Act.

Serving notice and what happens next

Notice has to describe the work clearly enough for the neighbour to understand what is planned and be served with enough lead time before work starts. If the neighbour agrees in writing, work can proceed on that basis. If they do nothing or dissent, a dispute is deemed to exist under the Act and surveyors get involved to produce an award.

It is common, and often cheaper, to use one surveyor agreed by both parties rather than each side appointing their own, though a neighbour is entitled to appoint their own surveyor if they prefer, with the building owner usually covering reasonable surveyor fees.

The schedule of condition

Before work starts, a surveyor typically records a schedule of condition of the neighbouring property, noting existing cracks, damp, or other defects with photographs. This protects both parties: the neighbour has evidence of the pre-work condition, and you have a record showing what damage, if any, existed before your build began.

We always welcome a schedule of condition being carried out properly. It removes a lot of the guesswork if a dispute ever arises later about whether the building work caused a particular crack.

Where this fits with our build programme

We cannot start work covered by the Act until the notice process has run its course and any award is in place, so we build the necessary lead time into the overall programme rather than treating it as an afterthought once a start date has already been promised.

If a neighbour dissents and a surveyor needs appointing, that can add time before groundwork starts, which is worth planning for early rather than discovering it once digging was supposed to begin.

Common questions