The short answer
A terraced roof is one slope among a row, so the work depends on how it joins the neighbours. The covering, the party wall line and the flashings at each side all need care, and the scaffold usually has to fit a narrow frontage, sometimes over the pavement. Tell the neighbours early, agree the junction details before work starts, and ask your building control body whether any formal notice applies.
How a terraced re-roof differs from a detached one: the shared line with next door, narrow access, scaffold and loft limits.
The line you share with next door
In a terrace the roof continues across the walls that divide the houses. At each side of your roof there is a junction where your covering stops and the neighbour's carries on, often with a brick party wall rising through the roof space between you. How that junction is built decides whether water gets in and whether the finished roof looks tidy from the street.
The detail varies. A masonry wall that stands above the roof is usually weathered with a lead flashing and sometimes a stepped apron. A wall that stops below the slope leaves a roof that runs on across it, and the covering has to follow the neighbour's line. Where your tiles are new and the next house's are old, the join may show a change of colour, which a good roofer will talk about before the work and not leave you to find on the day.
Whether any of the work touches the shared structure, and whether a formal notice is needed to a neighbour for it, depends on exactly what is done. We cannot give legal advice here. Ask a party wall surveyor, and tell your neighbours what you plan before the scaffold goes up. The whole job, step by step, is on our roof replacement page.
Fire, ventilation and the loft space
Terraced lofts are often one long space divided by brick walls, or by a thinner partition that does not reach the roof. Old houses may have lofts that were once open from one end of the row to the other, and some owners find a gap above a party wall. Ask the roofer to look along the loft and photograph the walls at each side during the survey, and to say what they see.
Fire spread between houses is a matter for the Building Regulations, and your building control body decides what is needed. Planning Portal also names a new covering that would behave very differently if a fire broke out, compared with the old, as a reason approval may be needed. That applies to any roof, but it matters more in a terrace, where one house's roof sits against its neighbours'.
A re-roof is also the moment to check ventilation. BS 5250 covers moisture in buildings, and the way the eaves are ventilated depends on the underlay and the pitch. Our guide to Building Regulations for re-roofing explains when approval is needed.
Access and scaffold on a narrow frontage
Many terraced houses open straight onto the pavement or a few steps from it. A scaffold on the front then stands on the public highway and needs the highway authority's licence; Section 169 of the Highways Act 1980 requires a licence where scaffold blocks any part of the highway, pavement included. A scaffold wholly on your own forecourt needs no licence, although a parking bay suspension could still be required.
West Sussex County Council wants at least 10 working days' notice before the scaffold is erected, and we line the licence up with your scaffolder. Who applies differs by county: Kent County Council's page says the scaffolding firm should, while other authorities are silent on it, so ask.
The back is its own puzzle. Many terraces have a narrow alley, a shared passage or no rear access at all, so tiles, battens and waste may have to be carried through the house or lifted over it. Say so at the survey, as it affects how the work is laid out and how long it takes. Check any gate, shared drive or wall you will be relying on belongs to you, and agree access with neighbours. Protecting gardens and conservatories at the back is part of a tidy site, and the plan for it should be explained to you in advance.
Dormers, loft rooms and permitted development
A terraced house has stricter limits on loft extensions. Class B of the permitted development rules caps the added volume at 40 cubic metres for a terrace house, against 50 cubic metres for other houses. Nor may a dormer sit on the main front slope if it faces a highway, and Class B falls away on article 2(3) land, such as a conservation area or National Park. If your terrace is in one, check with the council's planning team.
Roof windows fall under Class C, which has its own limits. A window set into a side-facing slope must have obscured glass, though in a terrace the sides are usually shared walls, so front and rear roof windows are the ones that count.
If a conversion is on the cards, plan it with the re-roof. Our answer on re-roofing before a loft conversion explains the order, and the one on the cost to re-roof a three-bed semi gives a national price guide for a comparable house.
Our written price comes after a look at both slopes and each side junction. Two or three pictures taken at the front and rear is all we need to begin the conversation.
More on this in Roof Replacement & New Roofs in Crawley
Two terrace questions
Do I have to tell my neighbours about a re-roof?
There is no harm in it, and good reason to. Scaffold may cross their frontage, noise carries through shared walls, and the roofers may need a look at the junction from their side. Whether a formal notice applies depends on what is touched, so ask a party wall surveyor, and keep any reply.
Can the neighbours' roof be left alone if mine is replaced?
Yes, but the join has to be made weathertight with proper flashings, and the old and new coverings may look different for a while. The roofer should photograph the junction before starting and explain how it will be finished. If the next-door roof is in poor condition, say so now rather than blame the new work later.