A title plan is not always an exact line
HM Land Registry explains that most title plans show general boundaries, not the precise legal boundary. The position or ownership of a fence is also not determined by a universal rule that one neighbour owns the left-hand side and the other the right. [1]
Start with the registered titles and relevant deeds, then consider the physical evidence. Do not infer a centimetre-accurate building line from the thickness of the red edging on a small-scale title plan. Where the evidence is unclear, a boundary surveyor and solicitor can help establish the issues that need resolving. [1][4]
Distinguish agreement from a transfer of land
Neighbours can make a boundary agreement recording their agreed boundary and maintenance responsibilities. Government guidance recommends legal advice and states that a boundary agreement cannot be used to sell or give away part of one owner's land. [4]
That distinction matters if the proposal is not merely clarifying an uncertain line but deliberately moving it to accommodate an extension. The paperwork must match the intended legal transaction; a note on a builder's drawing is not an adequate substitute. [4]
New walls at the line of junction
Section 1 of the Party Wall etc. Act distinguishes a wall astride the boundary from a wall wholly on the building owner's land. Written consent is needed for the astride-boundary route. Without it, the Act provides for the building owner to build wholly on their own land instead, subject to its requirements. [2]
A wall wholly on your own side may still need the section 1 notice where it is being built at the line of junction. Moving the wall face marginally away from the neighbour is not a sound basis for assuming that every party wall issue has disappeared. Nearby excavation must also be checked independently. [2][5]
Check below ground and above the wall
The Act contains particular provisions for necessary projecting footings and foundations associated with qualifying boundary walls. It also expressly prevents special foundations being placed on adjoining land without the adjoining owner's prior written consent. These are specific rights and restrictions, not general permission to encroach. [2][6]
The drawing review should therefore include the foundation arrangement and the proposed means of construction, not just the wall's visible face. Access and scaffolding require their own legal assessment under section 8 or a separate agreement. [3][7]
Planning permission does not settle ownership
The planning process considers land-use and design matters. It is separate from the parties' private ownership rights and the Act's procedures. A council-approved plan showing a boundary line should not be treated as a determination that one neighbour owns the disputed strip. [8][9]
If disagreement remains, keep the affected work on hold while obtaining advice rather than building first and relying on a later settlement. A clear resolution before construction avoids designing the project around a land right that has not been established. [4]