Do you need a party wall agreement for roof work?

1What a party wall is and why roofs are involved

A party wall is a wall shared by two properties, built on the boundary or straddling it. In a terrace the wall between each pair of houses is one, and in a semi-detached pair the wall dividing the two halves is another. Often the wall rises straight through the roof space, and the chimney breasts and stacks along it serve both sides.

That is why roofs come into it. A roof on a terrace or a semi is physically joined to its neighbour. Flashings turn up against the shared wall, one chimney stack may serve both houses, and timbers on either side may bear on the same brickwork. Work that cuts into or alters shared structure affects someone else's property as well as yours.

The law behind all this is the Party Wall etc. Act 1996. This page follows the plain-English GOV.UK guide on party walls and building work rather than quoting the Act itself, and it does not refer to individual sections.

A flat roof over a terrace extension, a hip end against a neighbour's gable and a lean-to built onto a boundary wall all raise the same question: who owns the wall, and who does your work touch?

2Roof work that is notifiable and work that is not

The GOV.UK guide lists the kinds of building work that must be notified, and chimney removal from a party wall is one. That is the item roofing projects meet most often. A homeowner who removes an old stack on a shared wall, perhaps to open up space for a loft conversion, has to notify the neighbour.

Ordinary maintenance on your own roof generally sits outside the process. Replacing slipped tiles, re-bedding a ridge, renewing a gutter or re-covering one side does not by itself cut into the shared wall. Flashings are the grey area: if lead is chased into the party wall as part of a new covering, ask whether the work is notifiable before you assume it is not.

Chimney-breast removal inside the house is a separate question again. The Planning Portal says building regulations approval will always apply, whoever owns the wall. Our answer on roofer or builder covers which trade deals with that. Asking the right question early costs a phone call; discovering a notice was needed after the work costs a great deal more.

3Notice periods and what silence means

For notifiable work the GOV.UK guide sets a window: the notice must reach your neighbour no less than two months, and no more than twelve, before building begins. That matters for a roofing job, because a start date cannot simply be fixed for next week, and a scaffold booking may need to wait for the notice period to run.

A notice is not a note you can leave unanswered. The guide is plain that silence does not mean the neighbour has agreed. If nothing comes back, the matter does not resolve in your favour, and a formal dispute process may follow.

The practical tip is to talk first. A short conversation about what is planned, when scaffolding goes up and who will be on site settles most worries before any paperwork. Write down what you agreed and send it by message afterwards. Neighbours tend to be more relaxed about work they have been told about than work that simply begins, particularly when a scaffold crosses the boundary or leans on their roof.

4Terraced and semi-detached roofs in Worthing

Worthing and the towns along the coast have many terraces, pairs of semis and blocks of flats, so shared walls are a regular part of roofing here. The roof over a terrace is often continuous, with a chimney stack straddling the line between two houses.

Before you commission anything, ask the roofer whether the job touches the party wall or a shared stack. If it does, plan the timing around the notice period and read what building control expects, which is in our answer on Adur and Worthing building control.

If your street is in a conservation area, planning questions may follow too: see roof work in Worthing and Adur conservation areas. A good roofer raises these before quoting, whichever side of the shared wall the scaffold stands on, and our guide on how to find a good roofer lists what to ask. We handle the practical side from the Watertight Worthing Roofing home page onwards. Treat this page as general information rather than legal advice, and speak to a surveyor if a wall is in dispute.