No. Permitted development rights apply only to houses. Flats and maisonettes are excluded, so an extension, loft conversion, roof alteration or garden outbuilding on a flat needs planning permission — whatever its size or design. Here’s why, what you can still do without applying, and how to get permission if you want to go ahead.
Why flats are excluded
Permitted development rights for homes are set out in Schedule 2, Part 1 of the General Permitted Development Order 2015 (the GPDO). Every class in Part 1 — Class A (extensions), Class B (loft conversions and roof additions), Class C (other roof alterations), Class D (porches), Class E (outbuildings) — grants rights to a dwellinghouse. The Order then defines “dwellinghouse” to exclude a building containing one or more flats, and a flat itself. A maisonette is treated the same way. The result is simple: a flat has none of these rights, so any external building work needs a planning application.
What this means for common flat projects
| Project on a flat | Permitted development? | What you need |
|---|---|---|
| Rear / side extension | No — Class A is houses only | Planning permission + freeholder consent |
| Loft conversion or dormer | No — Class B is houses only | Planning permission + freeholder consent |
| Garden room / outbuilding | No — Class E is houses only | Planning permission + rights to the garden |
| Roof alteration / rooflights | No — Class C is houses only | Planning permission + freeholder consent |
| New external windows / doors | No for flats | Planning permission + freeholder consent |
| Internal, non-structural works | Not a planning matter | Often just freeholder consent + building regs |
Notice the last column: for a flat, a planning grant is rarely the only consent you need. The garden, external walls and roof are usually retained by the freeholder.
The two things that actually decide a flat project
Because permitted development is off the table, redesigning to “stay within the limits” doesn’t help a flat. Two different questions decide whether your project happens.
1. Will the council grant permission?
Plenty of flat extensions and garden rooms are approved — the question is your odds for this project type in your area, and whether pre-application advice is worth getting first. A free check shows how comparable applications near you have actually been decided, so you’re not guessing.
2. Do you have the right to build?
This is the step most flat owners miss. Your lease usually reserves the garden, external walls and roof to the freeholder, so you’ll need a written “licence to alter” — and planning permission does not override your lease. Sort this before you spend on drawings: an approved application you have no right to build is worthless.
Frequently asked questions
Do flats have permitted development rights?
No. Permitted development rights under Schedule 2, Part 1 of the General Permitted Development Order 2015 apply only to a "dwellinghouse", which the Order specifically defines to exclude a building containing one or more flats, and a flat itself. So a flat or maisonette has no Class A–E rights, and works that would be permitted development on a house — a rear extension, loft conversion, roof alteration or garden outbuilding — need planning permission when the property is a flat.
Can I build an outbuilding or garden room if I live in a flat?
Not as permitted development. Class E (outbuildings) only applies to houses, so a garden room for a flat needs planning permission whatever its size. There is also a second hurdle: the garden is often communal or owned by the freeholder, so you may not have the legal right to build on it even if permission is granted. Check your lease and get the freeholder’s written consent before applying.
Can I extend a leasehold flat?
Possibly, but it always needs planning permission (flats have no Class A rights), and planning permission is only half the picture. Your lease usually requires the freeholder’s consent for any structural alteration, and you may need the agreement of other leaseholders if the work affects shared structure or land. Planning permission does not override your lease — even with permission, you cannot build without the right to the land and structure.
Do I need the freeholder’s permission to extend my flat?
Almost always, yes. Most leases reserve the external walls, roof, structure and garden to the freeholder and require written "licence to alter" consent for alterations. This is separate from planning permission: planning is the council’s consent, the freeholder’s licence is your private legal right to carry out the work. You need both.
What can I do to a flat without planning permission?
Internal, non-structural works inside your own demised space generally do not need planning permission — repainting, refitting a kitchen or bathroom, or replacing internal finishes. But your lease may still require the freeholder’s consent for some internal works, and structural changes (removing walls, altering the roof) typically need both freeholder consent and building regulations approval. Anything that changes the external appearance of the building needs planning permission.
Is it worth applying for planning permission on a flat?
Often yes — many flat extensions and garden rooms do get approved, but it depends on the local approval rate for your project type and on resolving the lease/freeholder side first. The cheapest way to find out is to run a free check for your address, which shows whether your project needs permission and how applications like yours tend to be decided nearby.