Party wall notices for an extension

Not every extension needs a party wall notice. The answer depends on what you will build, where it sits and how its foundations relate to neighbouring buildings. An extension may trigger more than one part of the Party Wall etc. Act 1996.

Three common extension scenarios

1. Working on a shared wall

Cutting into an existing party wall to insert a beam, or carrying out other work covered by section 2, can require a party structure notice under section 3. The ordinary notice period is at least two months. Minor activities, such as ordinary plastering or fitting shelves, are not generally notifiable.

2. Building a wall at the boundary

A new wall built up to the boundary on your own land may call for a line of junction notice under section 1. Building astride the boundary is different: it needs the adjoining owner's written consent. If they do not consent, the wall cannot simply be built across the line.

3. Digging near neighbouring foundations

Excavation within three or six metres of a neighbouring building may trigger section 6, depending on depth, location and construction. The rules are more technical than simply measuring the distance. Section 6 notices require plans and sections and are outside this site's automated PDF builder.

Does the extension's size matter?

A permitted-development extension can still require party wall notice. Planning permission, building regulations approval and the Party Wall etc. Act are separate matters. Conversely, a small extension is not automatically subject to the Act: the proposed works have to fall within the relevant provisions.

Practical checklist before preparing a notice

• Check whether the proposed work affects a shared party wall or structure.
• Ask the designer or builder where the new wall will sit relative to the boundary.
• Ask for excavation depths and nearby foundation information if foundations are proposed.
• Identify adjoining owners, including relevant leaseholders; some projects need several notices.
• Allow the correct statutory notice period before proposing a start date.

Can you prepare the notice yourself?

Yes. The government provides sample letters and says a homeowner does not need to employ a professional merely to give notice. You still need to identify the correct recipients and describe the work accurately. Our guided notice builder prepares documents from your answers for the supported work types.