If you are planning an extension or other works close to a neighbouring property, one of the most important considerations is the position of any new walls in relation to the boundary line.
Building owners regularly enquire whether they can build up to the boundary line, or even astride it. Whether or not this is permitted will depend on the location of the proposed wall, any existing structures, and the rights and obligations set out under the Party Wall etc. Act 1996.
In this guide, we’ll explain what is meant by building up to or astride the boundary line, when it is permitted, and what happens when the adjoining owner does not agree to the proposed works.
What Does Astride the Boundary Line Mean?
Building astride the boundary line involves constructing a wall so that half of it is built on the building owner’s land and the other half is on the adjoining owner’s land. In these cases, the Party Wall stands directly on the boundary line between the two properties.
A wall built astride the boundary line is generally considered a Party Wall under the Party Wall etc. Act 1996. As it sits on the land of both owners, it will typically be treated as a shared structure, with both owners having rights and responsibilities in relation to it.
This differs from a wall positioned entirely on one owner’s land but built up to the boundary line. In these cases, the wall will typically remain the sole property of the building owner, who will generally be responsible for its maintenance and upkeep.
When Can You Build Astride a Boundary Line?
For a building owner to have the legal right to build astride a boundary line, there are certain conditions that must be met and scenarios that must be present.
Building Astride an Existing Party Fence Wall
If there is already a Party Fence Wall separating the two gardens of the respective owners astride the boundary line, then the Party Wall etc. Act 1996 gives the building owner the right to demolish that wall and replace it with a new Party Wall forming part of the proposed extension.
In these situations, the existing wall already occupies the boundary line and is therefore treated as a shared structure, with the Act providing the legal framework for its demolition and replacement as part of the proposed works.
Building Astride the Boundary with Consent
If there is no existing Party Fence Wall built astride the boundary line, then the only way a building owner can legally build there is by obtaining the adjoining owner’s written consent.
This is one of the key principles under Section 1 of the Party Wall etc. Act 1996. While a building owner may have the right to build up to the boundary line on their own land, they cannot build astride the boundary and onto their neighbour’s land without written consent from the adjoining owner.
For this reason, we recommend discussions with adjoining owners at an early stage before plans are finalised. This helps prevent situations where costly and time-consuming processes, such as obtaining artist drawings, preparing surveyor reviews, and serving Party Wall Notices, are undertaken for works that ultimately cannot proceed in their proposed form.
What Is the Difference Between Building up to and Astride a Boundary Line?
Building up to a boundary line and building astride a boundary line are different in both a practical and a legal sense.
Building up to a boundary line means constructing a wall entirely on your own land, with the face of the wall positioned adjacent to the boundary line.
As discussed, building astride the boundary line means constructing a wall that sits partly on each owner’s land, with the centre of the wall located on the boundary itself.
This distinction is important legally, as both have different rights under the Party Wall Act. While walls built up to the boundary line can often be undertaken by the building owner without involvement from the adjoining owner, walls built astride the line require the presence of an existing Party Fence Wall or consent from the adjoining owner.
What Happens if an Adjoining Owner Refuses Consent?
When there is no existing Party Fence Wall and the adjoining owner does not consent to the proposed works, the building owner will generally need to amend their proposals.
The required amendments will depend on the nature of the adjoining owner’s concerns and whether they are willing to entertain a revised proposal. In cases where the adjoining owner is against having any part of the wall built on their land, the building owner will likely need to construct the wall entirely on their own land rather than astride the boundary line.
In other situations, the adjoining owner may be open to the construction sitting partly on their land but have reservations on certain elements of the proposed works, such as the size, location, or materials used. In these cases, discussions and negotiations among owners can result in amendments being made to the design, allowing work to proceed.
Why Choose Stokemont for Advice on Building up to or Astride a Boundary Line?
Planning to build astride the boundary line can be a stressful process, with the possibility of legal procedures and neighbourly disputes before work can commence. As an experienced team of Party Wall Surveyors, we can ensure you’re well prepared for every aspect of the process, preventing any unwanted surprises down the line.
To learn more about how we can assist with your Party Wall procedures, including building up to or astride the boundary line, contact our team today for professional and friendly advice.
FAQs
In many cases, people assume a Party Wall sits directly on the boundary line. However, this isn’t always the case. While Party Walls are often positioned on the boundary, the legal position can depend on documents, historical ownership arrangements, and other factors relating to the respective properties.
In cases of uncertainty, specialist advice from a Party Wall Surveyor may be required to establish the boundary position. It’s also worth noting that the legal boundary is not always located at the centre of the Party Wall.
Usually not. Building up to a boundary line is typically treated differently from building on or astride it, as the structure will be constructed entirely on the building owner’s land.
In many cases, a building owner will have the right to construct a wall wholly on their own land up to the boundary line, even where an adjoining owner objects.
However, Party Wall procedures may still apply depending on the nature of the proposed works and the position of the construction in relation to neighbouring structures.
