Anstey Horne

Party Wall or not a Party Wall?

Party Wall or Not?

If you are planning on building a new side return or rear extension, it is important to bear in mind the location of the new flank wall or Party Wall in respect of the boundary and your neighbours property.

A side return extension makes use of the sometimes awkward space at the side of the rear projection normally found on Victorian and Edwardian homes. This is also traditionally known as the closet wing. Side return extensions can incorporate this alleyway and extend the closet wing to the full width of the property. This layout is often mirrored in the adjacent garden. Often a wall, fence or combination of the two will delineat the boundary.

As part of the works the current boundary arrangement will need to be adjusted. This is necessary to make room and/or allow for the new wall enclosing upon the extension to be built.

Should you build a new Party Wall or not?

We are often asked to advise on the location of the new wall. Typically some degree of negotiation is required to find a scenario acceptable to both the Building Owner doing the work and the neighbour (Adjoining Owner).

If the gardens are currently separated by a timber or chain link fence the Building Owner will be required to serve a Notice to the neighbour before starting work.  The Notice will either be to build a new flank wall up to the line of junction but wholly on the Building Owner’s land, or to build astride the line of junction (or boundary) between the two properties to create a new party wall.

This is often referred to as ‘straddling’ the line of junction or boundary. The new wall will, in almost all circumstances, require removal of the existing fence to allow it to be built safely and finished from the Adjoining Owners side – normally either pointing or rendering.

Your neighbour will need to consent in writing to having the new wall built astride the line of junction. This will form a new Party Wall which is in effect a shared asset. If the neighbour does not consent the wall will have to be built wholly on your own land albeit flush against the line of junction.

Both parties can benefit from consent for a new Party Wall. We set out the potential benefits in more detail in another article. Even if the Adjoining Owner does not give consent to a new Party Wall the Act still provides rights of access to the Building Owner to build the new wall and remove any fence in the process.

Further Guidance when appointing a Party Wall Surveyor

For further information please see our Party Wall Fact Sheet.

We have also compiled some Party Wall FAQs.

See our previous article for guidance on choosing a Party Wall Surveyor.

The government have published an explanatory booklet with information for Building Owners’ and Adjoining Owners’ about the Party Wall process.


Anstey Horne advise both Building Owners and Adjoining Owners of their obligations and rights under the Act.

We can provide early advice by reviewing proposals and securing the necessary consents and Awards under the Act in a timely manner to allow a Building Owner’s work to proceed unhindered, or to protect the interest of an affected Adjoining Owner.

For advice direct from one of our Surveyors, please call our Enquiry line on 020 4534 3135.

If you are planning work that is covered by the Act, or if you have received notice of work from a neighbour and want advice on how best to protect your property please contact:

Geoffrey Adams

Geoffrey Adams

BEng (Hons) PdDip MRICS

Senior Director

Party Walls

Mark Amodio

Mark Amodio

MCIOB BSc (Hons)

Senior Director

Party Walls

Rickie Bloom

Rickie Bloom

BSc (Hons) MRICS


Party Walls