How Close to the Boundary Line can I build an Extension?

A Wall Built Astride the Boundary Line

Section 1(2) of the Party Wall etc. Act 1996 permits the build of a Party Wall or a Party Fence Wall astride the boundary if the Adjoining Owner consents to it. If the adjoining owner does not consent to a Party Wall Notice served under Section 1(2) in writing, you must build entirely on your land only. No reply to the Party Wall Notice does not mean an automatic consent, in fact, it is rather the contrary. If your notices are ignored by the Adjoining Owner for the full 24-day period (14 days for the initial notice plus 10 days for the reminder notice), it will be considered a deemed dispute. The dispute process must be carried out as so laid out by Section 10 of the Act and a Party Wall Award must be made. Once this is complete, you are permitted to build a wall solely on your land under Section 1(5).

A Wall Built Wholly on the Building Owner's Land

As you may suspect, it is (in most cases) challenging to gain the Adjoining Owner’s consent to build astride the boundary as this will entail half the thickness of the wall being on their land. To better your chances of gaining consent from your neighbour, we recommend talking to them in person and answering their questions or concerns about your project openly. Supplying the Adjoining Owner with a set of your proposed drawings can also help to paint a better picture of how the completed project will affect their property.

Many Building Owners prefer to propose to build under Section 1(5) from the beginning to minimise their chances of potential complications with neighbours during the Party Wall process. This must not be mistaken to mean that building under Section 1(5) eradicates the need of notifying your neighbour about your project.