Can my Neighbour Build on my Boundary Wall?

The boundary wall of your property is what separates you from your neighbour, and may be identified as a fence, a hedge, a physical wall, or an invisible line. It is important to understand that your responsibility over this boundary line will be outlined in the deeds of the property and with the land registry office, which will enable you to find out who is responsible for maintaining this boundary wall and what the specifics are in terms of ownership, planning permission, building works, and more. Moreover, it will help you determine whether your neighbour can build on the boundary wall.

Before we get into the specifics of building on or around a boundary fence wall, it’s also crucial to note that the property is surrounded by a boundary line which depicts the edge of your property and the start of the next, even if there is no visual structure in place. This is where disputes often start and where disputes between neighbouring properties can originate if the correct procedures are not followed, such as offering party wall notice and extension planning notice to neighbours and adjoining owners.

So, what do you do if your neighbours make moves to start building on what you believe to be the boundary wall? Let’s take a closer look.

To cut a long story short, under the Party Wall Act, any homeowner has the right to build up to the boundary line, or complete party wall works, without permission and can stretch their development to sit astride the boundary wall or line with your express permission.

Any work which involves or will impact the structural integrity of an existing boundary wall must be served in a written notice to you, the neighbour, at least two months before any work is due to commence. If you have an issue with the proposed works, you cannot demand it to cease – however, you can seek the services and advice of a party wall surveyor who will attend to the properties and carry out a survey on how the development should proceed.

Interestingly, work which stops even a mere centimetre from the edge of the boundary line falls under completely different rules and cannot be stopped – rather, the neighbour need only inform you as a matter of courtesy before commencing work. This means that any shared usage of the boundary line and land on either side of it will cease – with each property owner able to adapt and build on their own side as they see fit, provided they don’t hit or overstep the marked boundary line.

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If you or your neighbour wish to build up to and astride the boundary line, you can do with the express written permission of the other party. In addition, you cannot move or do anything to the boundary line without consulting with your neighbour, with a formal party wall award required before commencing any work.

If the boundary line falls within a party wall, for example, a shared fence or even an internal wall of the terraced house, this wall can be used as part of an extension though again notice must be served, and permission must be granted from the building owner. If the wall falls explicitly on either side, then this is not considered a boundary line and is the sole property of the homeowner whose side it falls on.

In short, no. The boundary line is there to mark specific territory, with the only potential work on a neighbour’s land being to lay the foundations for a new wall which meets the boundary line – and even in this case, the need for such an expansive foundation is rarely necessary for domestic property renovations and extensions.

If you or your neighbour is seeking permission to build up to or astride the boundary line, then formal notice must be served at least two months prior to the commencement of the work. If the other party is in agreement with the proposed plans, then this must be submitted within two weeks of receipt of the notice, otherwise, the request will be denied and the side that is seeking building permission will only be allowed to construct an extension up to their side of the boundary line.

In terms of the work itself, there are certain stipulations which must be met, for example taking care to minimise disruption while undertaking work and compensating for any damage caused to their neighbours as a result of the work being carried out. If damage to the existing boundary wall or fence line is suffered, then a new wall must be funded by the side doing the work, with wall surveyors able to offer more advice on the details around maintenance, building regulations, and the need for any other agreements prior to work starting.