Do I Need a Party Wall Notice for an Extension?

01

Why extensions commonly engage three parts of the Act

A typical rear or side extension can engage more than one procedure. Section 1 deals with certain new walls at the boundary, section 2 covers specified work to an existing party wall or party structure, and section 6 covers excavation near a neighbouring building or structure.

Planning permission and Building Regulations approval do not replace the Party Wall etc. Act 1996. They deal with different questions, so an extension can have planning approval and still require notice before relevant work begins.

02

A new wall at or close to the boundary

If you want to build a new wall astride the boundary, the adjoining owner must agree in writing. Without that agreement, the wall must be built wholly on your land. Building a new wall wholly on your land but up to the boundary can still require notice under section 1.

The precise boundary position matters. A Party Wall Surveyor cannot determine a disputed boundary under the Act, so unresolved ownership or boundary questions may need to be dealt with separately.

03

Work to an existing party wall or structure

An extension may involve cutting steel beams, flashings or other structural elements into a party wall; raising or rebuilding part of it; exposing it to weather; or removing projections that obstruct the new work. Some of these operations fall within the rights and notice duties in section 2.

Ordinary minor fixings are often too limited to require notice. The relevant distinction is not simply whether the wall is shared, but what work is proposed and whether it falls within the Act.

04

Excavation within three or six metres

New extension foundations frequently trigger section 6. The three-metre test compares the proposed excavation with the depth of the adjoining owner’s foundations. A separate six-metre test can apply where deeper excavation falls within a line drawn downwards at 45 degrees from the bottom of the neighbouring foundations.

Distance alone is not enough to decide the issue. Foundation depth and position need to be checked using suitable drawings and, where necessary, information about the adjoining structure.

05

When should notice be served?

The government guide explains that section 2 work generally requires at least two months’ notice, while relevant section 1 and section 6 work generally requires at least one month. A neighbour can agree to an earlier start but is not required to do so.

Notices should be based on sufficiently developed information and are normally valid for twelve months. Serving too late can delay the intended start; serving before the scheme is settled can create avoidable amendments or fresh notice work.

06

What should I send for an initial review?

A useful first review normally needs the property postcode, existing and proposed drawings, sections showing foundation depth, the intended start date and any information already shared with the neighbour. A review can then identify the likely notice routes and any missing technical information.

• Existing and proposed plans
• Sections and foundation details
• Property and adjoining-owner details
• Intended construction start date