The short answer: sometimes. Re-covering a roof inside its existing upstands often needs no notice, but cutting into a shared wall, raising a parapet on the boundary or building the roof up against the wall can bring the Party Wall etc. Act 1996 into play. Notice is the building owner's to serve, and the facts of the job decide.
What is a party wall, and why do flat roofs meet one so often?
A party wall is a wall on the boundary between two properties that both of them rely on, like the wall dividing two terraced houses. The Act's own definitions reach further than that, and GOV.UK's guidance, "Party walls and building work", sets them out in plain terms.
Flat roofs on terraced streets meet one more often than any other roof does. A back addition or a side return infill runs right up to the boundary, so its covering usually turns up the party wall as an upstand, with a flashing chased into the brickwork above it. Some have a parapet standing on the line of junction, and a few are shared outright, one covering laid across two properties.
What kinds of roof work can bring the Act into play?
Work that cuts into, raises or rebuilds the shared wall can, and so can work that needs access from the neighbour's side. Whether a particular job does depends on its details, so read this as a list of things to raise early rather than a ruling:
- Cutting into the wall: chasing in a new flashing, or seating the ends of a new deck or joists in the brickwork.
- Raising or rebuilding a parapet that stands on the boundary.
- Raising the roof level against the wall. A warm roof build-up adds depth, so the upstand climbs higher and may need a fresh chase above the old one.
- Working from next door: scaffolding, access or protection on the neighbour's side of the line.
The added depth is explained on our warm roof conversion page. A full strip and rebuild is the job most likely to touch several of these at once, because the deck and its bearings come out as well as the covering.
What roof work often does not need notice?
Work that stays on your side of the wall and leaves its fabric alone often does not. A new covering laid inside the existing upstands, without cutting into the brickwork, is the usual example, and an overlay on an existing felt roof can sometimes be detailed that way.
Often is not always. Even a repair to a leaking flashing can mean raking out and repointing the chase in the shared wall, so ask the question rather than assume the answer. Only the facts of the job decide, and where there is doubt a party wall surveyor is the person who says.
Who serves the notice, and what do we do?
The building owner does: the person having the work done serves notice on the neighbour, not the roofer. At the inspection we point out where the planned work meets a party wall, so that you can deal with notice before a start date is fixed.
We do not serve notices, act as party wall surveyors or give legal advice. If your position is unclear, a party wall surveyor or a solicitor is the right person to ask, and the conversation is worth having before the roof is booked rather than after.
Why does notice change the start date?
Because the notice comes first: for work on a party wall itself, GOV.UK's guidance, "Party walls and building work", says notice must be given between two months and a year before the work starts. An agreement or an award can add time on top, so check the guidance, or ask a surveyor, before you agree a date with anybody.
In practice the roof's programme should begin with the notice, not the other way round. A neighbour may agree in writing; if they do not, the usual route is that surveyors are appointed and an award records how the work will be done, which takes longer. Dated photographs of the wall and the neighbour's side before anything starts help everybody, whichever way it goes.
What about leasehold flats and shared roofs?
A roof over flats raises the same question with more people in it. Who instructs the work, and who serves any notice, follows who owns and maintains the roof, which the lease usually settles; our guide to who is responsible for the roof in a leasehold flat walks through it. On converted terraces like the ones described on our Clapham page, the roof over a back addition can belong to one flat while the flat above it belongs to another, so the people to tell may live in the same building as well as next door. For a landlord or a block manager, the notice belongs in the programme beside any consultation the lease requires.