If you live in a semi-detached or terrace house you share a wall (or walls) with your neighbour - this is known as the party wall. It separates buildings belonging to different owners.
Where a wall separates two different size buildings, the only part that is used by both properties is considered to be a party wall. The rest belongs to the person on whose land it stands.
You must get your neighbour's agreement before you can start any building work such as:
Damp proofing works
Some internal refurbishment
In some cases, excavating or constructing foundations for a new building within three or six metres of neighbouring properties will also need written agreement.
The Party Wall Act
Since the Party Wall etc Act 1996 came into force, homeowners in England and Wales have a procedure to follow when building work involves a party wall or party fence wall.
The Act is designed to minimise disputes by making sure property owners use a surveyor to determine the time and way in which work is carried out. You can use an agreed surveyor to act for both property owners should problems arise.
The Act allows you to carry out work on - or next to - a shared wall. At the same time protecting the interests of anyone else who might be affected by that work.
What doesn't the Act cover
The Act doesn't cover everyday minor jobs that don't affect the neighbours' half of a party wall including:
Screwing in wall units or shelving
Adding or replacing some recessed electrical wiring or sockets
Replastering your walls.
What is covered by the Act?
There are some things that you can only do to a party wall with the written agreement of the adjoining owner including:
Cutting into a wall to take the bearing of a beam, for example for a loft conversion
Inserting a damp proof course all the way through a wall
Raising the whole party wall and, if necessary, cutting off any objects stopping this from happening
Demolishing and rebuilding the party wall
Underpinning the whole or part of a wall
Protecting adjoining walls by cutting a flashing into an adjoining building
Building a new wall on the line of junction between two properties
Excavating foundations within three metres of an adjoining structure and lower than its foundations
Excavating foundations within six metres of an adjoining structure and below a line drawn down at 45o from the bottom of its foundations.
What do I do next?
If you intend to do any of these things, you must give written notice to your neighbours at least two months before starting any party wall works. Or one month for 'line of junction' or excavation works.
If a tenant or leaseholder is in the building next door, you will need to notify the landlord in addition to the person(s) living in the property, that you want to carry out building work to the party wall.
Where there is more than one owner of the property or more than one adjoining property, you must also let them know.