Why permitted development stops at the front door of a flat
Permitted development rights for home alterations belong to houses, and the order that grants them defines a house in a way that leaves flats out.
The Town and Country Planning (General Permitted Development) (England) Order 2015 sets out householder rights in Schedule 2, Part 1. Every class in that Part, from rear extensions to Class C "other alterations to the roof", applies to a dwellinghouse. The order does not treat a building containing flats, or a flat within such a building, as a dwellinghouse for this purpose. A maisonette, which is a self-contained home on two floors within a larger building, is treated as a flat for this purpose too.
That matters because Class C is the route a house owner uses for a roof window or rooflight. On a house it allows a new rooflight provided it projects no more than 150mm from the roof plane, sits no higher than the highest part of the roof, and meets the side-facing glazing conditions. Our guide to planning permission for rooflights in Cambridge covers those limits in detail. None of them can be relied on for a flat, because the class never applies in the first place.
The same is true whether the flat is purpose-built, a converted Victorian house or a unit above a shop.
When a new rooflight in a flat needs planning
Without permitted development, the question becomes whether the work counts as development at all, and a new opening in a roof usually does.
Planning law excludes works that do not materially affect the external appearance of a building. Cutting a new skylight into a slate or tile slope visible from the street, or adding a raised flat rooflight or lantern to a flat roof, changes how the building looks, and the council will normally expect an application. A small unit on a hidden rear slope, set almost flush with the tiles, is a closer call, and it is the council's view that counts rather than the installer's.
A like-for-like replacement is different. Swapping a tired roof window for one of the same size, in the same opening, with a similar frame colour and profile, may not materially change the appearance, and it may not need permission. A larger unit, a different shape or a raised profile brings the question back. If you want certainty, you can apply for a lawful development certificate, which records the council's view in writing before any work begins.
- Usually needs an application: a new rooflight on a visible slope, a new lantern or raised flat rooflight, an enlarged opening.
- May not need one: a replacement in the same opening that matches size and appearance closely.
- Always needs listed building consent: any alteration to a listed building, whether it is a house or a flat.
Checking with Greater Cambridge Shared Planning
For flats in Cambridge city and South Cambridgeshire, the planning authority is Greater Cambridge Shared Planning, and it is the right place to confirm what your building needs.
GCSP handles planning for both Cambridge City Council and South Cambridgeshire District Council. Its website explains the application types, and the council's constraints map shows whether your address sits in a conservation area or is listed. If your flat is further out, in Ely, St Ives or Saffron Walden for example, the authority will be East Cambridgeshire, Huntingdonshire or Uttlesford instead.
A short description of what you want to do, a photograph of the roof slope and a sketch of the rooflight position are usually enough to start a conversation or prepare an application. The drawings for an application show the skylight in elevation and on plan, so it helps to fix the size and position early. That is also where the light plan earns its place: the survey works out where the sun patch will fall in the room, so the opening you apply for is the one you actually want to live with. Our light planning page explains how we work that out.
The lease and the freeholder
Planning is only one of the consents a flat owner may need, because the roof is often not theirs to alter.
In many leasehold flats the roof and the main structure are kept by the freeholder, and the lease will say what the leaseholder can and cannot change. Cutting a new opening or replacing a rooflight may need the freeholder's written consent, and some leases set out a formal process, a fee or conditions about who carries out the work. In a share of freehold building, the other owners are usually involved too.
Leases vary a great deal, so read yours and speak to the freeholder or managing agent before you apply for planning or book any work. If the wording is unclear, a solicitor or conveyancer can explain what it means for your building. We cannot give legal advice on a lease, and nothing on this page should be taken as a view on what yours allows.
Building Regulations still apply
Whatever the planning position, a new rooflight in a flat is building work, and the Building Regulations apply in the same way as they do to a house.
A new opening in a roof usually needs Building Control approval, covering the structure around the opening, thermal performance under Part L, safety glass overhead under Part K and, in blocks of flats, fire spread between homes under Part B. Separating walls and roofs between flats carry fire rules that affect where a skylight can go. We handle the Building Control notification where the work is notifiable and install to current Building Regulations. Our guide to Building Regulations for rooflights sets out each part.
| Consent | House | Flat or maisonette |
|---|---|---|
| Planning | Often permitted development | Usually an application |
| Building Regulations | Usually needed | Usually needed |
| Freeholder | Not normally | Often, check the lease |
| Listed building | Consent needed | Consent needed |
For a top-floor flat the light often makes the effort worthwhile. A converted loft room or a deep flat under a hipped roof can be dark at the back, and a well-placed skylight lights the part of the room that windows never reach. Our guide to which way a skylight should face shows what each slope gives, and the skylight and rooflight installation homepage explains how we plan and fit them.
Questions people also ask
Does a maisonette have permitted development rights for rooflights?
No. A maisonette sits within a larger building and is treated as a flat for permitted development, so the householder rights in Part 1, including Class C for rooflights, do not apply. A new rooflight that materially changes the outside of the building usually needs planning permission.
Can I replace an existing skylight in my flat without planning?
Often, if the new unit matches the old one closely in size, position and appearance, because it may not materially affect the building's appearance. Enlarging it or changing its profile brings planning back into question. Our guide to skylight replacement options explains the choices.
Do I need freeholder consent for a rooflight?
Many leases keep the roof with the freeholder, so consent is often required, but it depends on the wording of your lease. Check it and speak to the freeholder or managing agent before applying for planning or booking work.
Is a sun tunnel easier to get approved in a flat?
A sun tunnel has a small dome on the roof, so its effect on appearance is usually less than a full rooflight, but a flat still has no permitted development route, so check with the council. It still needs the freeholder's agreement where the roof is theirs. See sun tunnel installation for how they work, or book a light survey.
