The owner of a boundary wall is responsible for keeping it safe, and your deeds are the place to find out who that is. A masonry garden wall standing astride the boundary is a "party fence wall" under the Party Wall etc. Act 1996. Building one, or raising or rebuilding one, means serving written notice on your neighbour first.
Some questions, especially about retaining walls, have no simple official answer. This is general information for England, not legal advice.
Who owns a boundary wall?
Start with the title register and plan for your home, and ideally your neighbour's, from HM Land Registry. The register may say who owns or must maintain a wall, but HM Land Registry says many do not. A "T" mark on a deed plan usually signals ownership or a duty to repair, but it only counts if the written deed refers to it.
A covenant to maintain a wall does not on its own make it yours. There is no left-or-right rule either, and how a wall is built does not prove who owns it.
If ownership cannot be established, HM Land Registry's guidance is to treat the wall as a shared boundary and agree any change or replacement with the neighbour. Who owns the fence explains title plans and T-marks in more detail.
Who is responsible if a boundary wall is collapsing?
The owner. Citizens Advice says that if a neighbour's wall looks dangerous, tell them, because they may not know. If they do not repair it, you can report a dangerous structure to your council. If the wall is yours, your deeds may require you to keep it in good repair, and if it is not safe your neighbour or the council could take action against you.
The Planning Portal says garden walls do not need Building Regulations approval but must be structurally sound and maintained. It suggests expert advice when a brick wall leans more than 30mm for a half-brick (single-skin) wall, 70mm for a one-brick wall or 100mm for a brick-and-a-half wall. The same goes for cracks wider than 2mm, horizontal cracks that pass right through the wall, and any wall holding back soil.
Liability for damage or injury from a fallen wall is a civil matter that depends on the facts, so take legal advice if it comes to that. If a wall has fallen onto a road or pavement, report it to the council, and if anyone is in danger, call 999.
Who is responsible for a retaining wall between gardens at different levels?
There is no official rule of thumb. The gov.uk Party Wall booklet, HM Land Registry and Citizens Advice do not deal with walls that hold up a neighbour's higher garden. Start with the deeds and where the wall stands. Beyond that it is a civil matter that turns on the facts, so ask a solicitor who handles property disputes.
What the sources do say:
- If the wall stands on the boundary and separates the two gardens, it may be a party fence wall, and the Party Wall Act notices below would apply to work on it.
- A wall built entirely on one owner's land is not a party fence wall, even if its footing projects under next door.
- Digging for a new retaining wall near a neighbour's house or garage can fall under the 3m and 6m rule.
A retaining wall rebuild is priced after a visit. See garden walls and the garden wall cost guide.
When does the Party Wall Act apply to a garden wall?
Does a garden wall count as a party wall?
A masonry garden wall that stands on land of both owners and separates the two gardens is a "party fence wall". The gov.uk booklet says this does not include wooden fences. A garden wall built wholly on one owner's land is a boundary wall, not a party wall.
Building a new wall on the boundary
Serve notice at least one month before work starts. You can only build astride the boundary with your neighbour's written consent. If they agree, the cost is shared in proportion to each owner's use of the wall. If they do not consent in writing within 14 days, you must build wholly on your own land, at your own expense.
You still serve the one-month notice to build a wall right up to the line on your own land.
Can the foundations go under next door's land?
Yes, normal projecting footings can be placed under the neighbour's land, but only where they are necessary. "Special foundations", meaning ones with beams or rods to spread the load, need their written consent. You must pay for any damage the wall or its footings cause.
Repairing or rebuilding an existing party fence wall
Raising, repairing, or demolishing and rebuilding a party fence wall needs a party structure notice at least two months before work starts. Where the work is needed because of a defect, the cost is shared in proportion to each owner's use of the wall and responsibility for the defect.
The 3m and 6m rule for digging near next door
A one-month notice, with plans and sections, is needed if you dig:
- within 3m of a neighbour's building or structure and deeper than the bottom of its foundations, or
- within 6m of it and the dig would cut a line drawn down at 45 degrees from the bottom of its foundations.
The notice must also say if you plan to strengthen or safeguard the neighbour's foundations.
What if my neighbour doesn't reply?
For a party structure notice or an excavation notice, no reply within 14 days means a dispute is treated as having arisen. For a new wall astride the line, no written consent means you build on your own land.
Surveyors and who pays
If there is no dispute, the Act does not require a surveyor. If there is one, the owners appoint one agreed surveyor, or one each, who choose a third if needed. They act impartially and make an "award" setting out the work. The booklet says the building owner usually pays the costs of the award when the work is for their benefit.
What the Act does not do
- It does not settle where the boundary is. That goes to mediation or the courts, and HM Land Registry cannot decide boundary disputes.
- It is separate from planning permission and Building Regulations.
- It has no enforcement procedure. Failing to serve notice is a civil matter, and the neighbour can go to court for an injunction.
Your neighbour cannot stop you using your rights under the Act, but they can influence how and when the work is done. They must let workers and surveyors in for the work, after 14 days' notice except in an emergency.
Questions
Does a wooden fence count as a party wall?
No. The Party Wall etc. Act 1996 covers masonry walls. The gov.uk booklet says a party fence wall does not include wooden fences, so a timber fence on the boundary needs no party wall notice.
Do I need a party wall surveyor to build a garden wall?
Only if there is a dispute. If your neighbour agrees in writing to the work in your notice, the Act does not require a surveyor. If they object, or do not reply in time, surveyors are appointed to settle it.
Who pays to rebuild a shared boundary wall?
If it needs rebuilding because of a defect or disrepair, the gov.uk booklet says the cost is shared in proportion to each owner's use of the wall and their responsibility for the defect. Otherwise, the Act's general rule is that the owner who wants the work pays for it.
Does a party wall agreement mean I don't need planning permission?
No. The Act is separate from planning and Building Regulations. A wall over 1m next to a road or over 2m elsewhere still needs planning permission, whatever the party wall position.
My neighbour built a wall on the boundary without serving notice. What can I do?
The council does not enforce the Act. Failing to serve notice is a civil matter, and the gov.uk booklet says the neighbour affected can seek an injunction or other legal remedy through the courts. Talk to your neighbour first, then take legal advice.