Building on the Boundary or Line of Junction

The party wall act permits you to build up to or astride the line of junction / boundary with your neighbour —

but the correct notices must be served and the correct process followed.

Can I build up to or over the boundary line?

If you want to build a party wall or party fence wall astride the boundary line (called the “Line of Junction” in the Party Wall Act), you must tell your neighbour by serving a notice.

The Act sets out the precise information you must tell your neighbour and you must tell your neighbour in writing. It is common to use a standard Party Wall Notice to make sure that this is done. We’ve uploaded templates to help you, the correct notice is a “Section One” notice. You may feel happier appointing a party wall surveyor to do this for you. Collier Stevens has a competitive fixed fee service which includes serving the correct notices.

There is no right to build astride the boundary if your neighbour objects. If your neighbour does object then you might have to alter your drawings so it is best to check early on.

You must also inform the adjoining owner if you plan to build a wall wholly on your own land, but up against the boundary line.

If you do build a wall astride the boundary line, it will be a party wall. If you build wholly on your land, it will not.

If you build inside your land away from the boundary (even by a small amount) you will not need to notify your neighbour, although if you are forming foundations, you may need serve a notice under Section 6 if their building is close enough. See also “Excavating Near Your Neighbour”.

When do I need to serve a notice if I want to build on or astride the line of junction (boundary)?

At least one month before the planned starting date for building the wall.

What happens after I serve a notice to build astride the boundary line?

If the adjoining owner agrees in writing, within 14 days to the building of a new party wall astride the boundary line, the agreed work may go ahead. If the adjoining owner does not respond, or objects to the proposed new wall astride the boundary line, you must build the wall wholly on your own land, and wholly at your own expense.

In some cases, the cost of building the wall may be shared with your neighbour, especially where the benefits and use of that wall will be shared — for instance a garden wall. Usually the surveyors will decide who pays what if it is not clear. In nearly all cases the whole cost is met by the person doing the work.

If, in the future, the neighbour wishes to use the wall then they will have to pay compensation to the person who built the wall (or his successors).

The Act also grants a right, if it is absolutely necessary, to place ordinary footings for the new wall under your neighbour’s land.

What happens after I serve a notice to build up to, but not over, the boundary line?

You may start work one month after your notice was served. This work may include footings and foundations that extend under the adjoining owner’s land.

The wall will be built wholly at your own expense and you will be expected to compensate any adjoining owner for any damage to his property, garden or plants caused by the building of the wall, or the placing of footings and foundations.

What happens if I cannot agree with my neighbour?

If there is a disagreement about any work on a boundary line, including compensation, then Party Wall Surveyors can be appointed and the dispute settled using the resolution procedures in the Party Wall etc Act. This usually means that a Party Wall Award is agreed. For more details about disputes, see ‘Resolving disputes’.