No permitted development for dormers anywhere in the city
Bath works differently from almost every other English town. The whole city, out to its old municipal boundary, is a World Heritage Site. It was inscribed in 1987 and again in 2021 as one of the Great Spa Towns of Europe. Under the national rules a World Heritage Site is protected land, and on protected land the permitted development right for roof extensions simply doesn't apply.
So a rear dormer that most English homeowners could build without asking needs full planning permission here. That goes for a Georgian townhouse in Camden and for a 1930s semi off Wellsway alike. Most of the city also sits in the Bath Conservation Area, which covers 1,486 hectares and about 50,000 people, and Bath has more than 5,000 listed buildings.
None of that means no. It means applying first, with drawings for a design the planners can accept. Rooflights are the exception. On an unlisted house, ones that stand no more than 15cm proud of the roof slope can still go in without permission.
Hidden roofs behind the parapets
The Georgian terraces hide their roofs. The council's city-wide character appraisal describes "M" shaped roofs: two pitches with a lead-lined valley gutter between them, tucked behind a stone parapet. In Lower Lansdown and Camden the usual pattern is three storeys over a basement with a habitable attic on top. On these houses the work is more often improving an attic than creating one, and because most are listed, listed building consent comes before anything else. The council is blunt that unauthorised work is a criminal offence.
The Victorians changed the roofline. In the words of the Bear Flat and Oldfield Park appraisal, "Parapets were out, slate roofs and gutters were in." The 1840s villas on Oldfield Road have gabled slate roofs with deep eaves. Pitched roofs like these are where most Bath conversions happen.
They're also where the Bath Preservation Trust comments. It called one side dormer in Maple Gardens "unnecessarily large" and said grey timber cladding was wrong for the cheeks. On Tyning Terrace in Fairfield Park it objected to balcony-style rooflights on the front slope, noting that local conversions usually keep bigger dormers at the back and rooflights small. Design to that and you start on the right side of the argument. Match the slate too. The appraisal names Welsh slate in soft blues and purples, with clay pantiles or double Roman tiles in some streets.
Which conversion suits which Bath house
Here's how each type tends to work on the city's houses. Every one has a full guide behind it.
Rooflights only. The one roof change most Bath owners can make without a planning application, as long as the house isn't listed and the rooflights stay within 15cm of the slope.
Rear dormer. Still the usual answer on the Oldfield Park and Bear Flat terraces, but here it goes through planning. Keep it off the street side and below the ridge, and clad the cheeks in something that sits well against slate.
Mansard. Bath has real Georgian ones. Lambridge Place has a terrace with a visible mansard and dormers built into it. A new mansard on a listed terrace needs listed building consent as well as planning permission, so bring in an architect who knows the city first.
Hip to gable. Suits the semis that fill the residential streets of Weston and Newbridge and the interwar houses around Wellsway and Odd Down. Elsewhere this is usually permitted development. In Bath it isn't, and on a street of matching hipped roofs the planners will ask how one squared-off gable looks.
Read our full guide: Hip-to-Gable Loft Conversions: What It Involves and Which Houses It Suits →
L-shaped dormer. Fits a Victorian terrace with a back wing. The Bear Flat and Oldfield Park appraisal lists dormers among the small changes wearing away the area's character, so a double dormer gets a hard look. Keep each part smaller than you'd like.
Extra bedroom. The usual aim in a family house. A shared house is different. The whole city has been under an Article 4 direction for HMOs since July 2013, and taking a house past six residents needs planning permission.
Home office. Bath sits in a hollow in the hills, and the top of the house is the place to look out at them from. Get a data cable run up while the walls are open.
Read our full guide: Loft Home-Office Conversion: What Works Well Up There and What to Specify →
En-suite. Work out the soil pipe route first. Behind a parapet with a valley roof, the pipe and its vent both need thought, and on a listed house the new pipework is part of what the consent covers.
Planning. Assume any dormer, hip-to-gable or mansard needs planning permission, because the World Heritage Site status removes the usual rights across the whole city. Add listed building consent if the house is listed.
Cost. We don't publish a Bath price. A listed Georgian attic and a 1930s semi are completely different jobs. Three quotes from firms who have built here before will tell you more than any average.
Who checks the work, and where to look first
Planning and building control are both Bath and North East Somerset Council. Before you pay for drawings, look up your street on the council's planning register. Approved dormers a few doors down are the best evidence you'll get of what an officer will accept. Listed building questions go to the council's conservation team.
Building control is based at Lewis House on Manvers Street and books the inspections. When the job is done you get a completion certificate. Keep it with the deeds, and on a listed house keep the consent with it.
Where these facts come from
- UNESCO World Heritage in Bath, the story so far (B&NES)
- Permitted development rights for householders, technical guidance (GOV.UK)
- Conservation areas (Bath Preservation Trust)
- Bath City-wide Character Appraisal SPD (2005)
- Bear Flat and Oldfield Park character appraisal (2020)
- Listed buildings (B&NES)
- Article 4 direction for HMOs, 2013 (B&NES)
- HMO SPD frequently asked questions (B&NES)
- Contact B&NES Building Control
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Questions people in Bath ask
How do I know if my house is in the World Heritage Site?
If it's inside the city of Bath, it is. The site was inscribed without a map, and in 2005 the World Heritage Centre confirmed that the city boundary is the site boundary. Outside the city, ask the council.
My Georgian house already has attic rooms. Do I need consent to upgrade them?
If the house is listed, very likely. Listing protects the whole building, inside as well as out, and any alteration that affects its character needs listed building consent. Talk to the conservation team before a builder lifts a floorboard.
Can I add a loft bedroom to my student let in Oldfield Park?
Possibly, but check the numbers. A shared house for three to six people is a C4 HMO. Go above six and it needs planning permission as a larger HMO, on top of the permission the dormer needs anyway. The Oldfield and Westmoreland wards are also under the council's additional HMO licensing, so check your licence as well.
I live on Bath Western Riverside or the old MoD site at Foxhill. Do the same rules apply?
Yes. New estates inside the city are in the World Heritage Site like everywhere else, so a dormer needs an application. Find out early whether your roof is built from trusses, because that means a steel frame and a different quote.