Permitted development on a flat and what applies
A building containing flats is not a dwellinghouse under the GPDO, so extensions, dormers and outbuildings all need permission. Here is what still counts as permitted development.
A flat has almost no permitted development rights, and the reason is a single definition. Article 2 of the General Permitted Development Order 2015 defines a dwellinghouse so as to exclude a building containing one or more flats, and a flat contained within such a building. Every class in Part 1 of Schedule 2, which carries the familiar householder rights for extensions, roof alterations, outbuildings, porches and hard surfaces, is drafted by reference to a dwellinghouse. So permitted development flat rights are, for practical purposes, non-existent for the things leaseholders most want to do.
Why most householder rights exclude flats
The exclusion is deliberate rather than accidental. Householder rights assume one household controlling a building and its curtilage, with the consequences of an extension falling mainly on that household. In a building of flats the curtilage is shared, the structure is shared, and an alteration by one occupier affects the others.
The drafting is blunt. Where a class says "dwellinghouse", a flat is outside it, and so is the whole building containing the flat. A ground floor flat with its own garden and its own front door has no Part 1 rights, because the building it sits in contains flats.
That catches a long list of works:
- rear and side extensions and conservatories
- loft conversions, dormers and rooflights
- outbuildings, garden rooms and sheds in a shared or demised garden
- porches
- hard surfaces and driveways, so the usual rules on front garden paving and permeable surfaces simply do not reach a flat
- chimneys, flues and soil vent pipes
- garage conversions where external alterations are involved
The arithmetic people apply to garden structures, including the 50 per cent curtilage rule, has no application either, because the class that contains it does not apply in the first place.
Rights that do apply to a building containing flats
A smaller set of classes is drafted more widely, and these are the ones worth knowing.
| Class area | Position for flats |
|---|---|
| Gates, fences, walls and other means of enclosure | Applies generally, with the usual height limits of 1 metre next to a vehicular highway and 2 metres elsewhere |
| Exterior painting | Applies to any building, subject to the restriction on advertisement |
| Microgeneration | Several classes are drafted by reference to a dwellinghouse or a block of flats, so solar panels on a block can be permitted development |
| Microwave antennas | The domestic antenna class covers a block of flats, with limits on number, size and position and tighter limits on article 2(3) land |
| Additional storeys on a block of flats | Part 20 permits new dwellings above an existing detached block within limits, subject to prior approval |
| Changes of use in Part 3 | Operate on buildings and uses rather than on dwellinghouses, so routes such as Class MA are unaffected by the flat exclusion |
Read the specific class text each time. Several of these have been amended since 2015 and the position on flats differs class by class rather than following a single rule.
Part 20 deserves a mention for landlords. The upward extension classes allow new dwellings to be built above an existing building, including a detached block of flats, subject to prior approval on matters including external appearance, amenity and construction impacts. Those rights carry strict limits on height, on the age of the building and on the land they apply to, and they are the main route by which a block of flats gains anything at all.
Maisonettes and the dwellinghouse definition
Maisonettes are where the definition bites hardest, because owners of a two-storey maisonette with its own front door and its own garden reasonably assume they own a house.
The definition does not look at how the unit feels. It asks whether the building contains one or more flats. A building divided horizontally into two maisonettes contains flats, so neither unit has Part 1 rights and neither does the building.
Two consequences follow. A maisonette owner needs planning permission for a rear extension where the identical extension on a neighbouring terraced house would be permitted development. And the application is made on the full application form rather than the householder form, because the householder route is reserved for dwellinghouses. The fee is calculated differently as a result, so take the figure from the current fee schedule rather than assuming the householder rate.
Conversely, a building converted back into a single dwellinghouse regains Part 1 rights once the conversion is lawfully complete, which is occasionally a reason to do the conversion first.
Satellite antennas, flues and microgeneration
These three come up constantly and they behave differently from one another.
Antennas on a block of flats are covered by the domestic antenna class, with limits on how many may be installed, their size, and where they may go. The restrictions are tighter in a conservation area and on other article 2(3) land, and installation on a listed building needs listed building consent regardless of the planning position.
Flues are not covered. The Part 1 class dealing with chimneys, flues and soil vent pipes is a dwellinghouse class, so a flue for a boiler replacement or a wood burner in a flat needs planning permission where it is visible externally. In practice councils often take a pragmatic view on a rear elevation, and that is not the same as the work being permitted.
Microgeneration is more generous. Several classes in the microgeneration Part refer to a dwellinghouse or a block of flats, which is why roof-mounted solar on a block is often permitted development while the extension below it is not. Heat pumps are a separate question again, with their own limits on size, position and noise, and the class text should be read rather than assumed.
Communal areas and who can apply
Anyone may apply for planning permission on land they do not own, and that is the key to works affecting communal areas.
What the system requires instead is notice. The application must be accompanied by the correct ownership certificate, and where you are not the sole owner of the application site, notice has to be served on the other owners. For a leaseholder with a short lease, the freeholder is an owner for this purpose and must be served. Getting the certificate wrong is a validation issue at best and a ground for challenge at worst.
Three practical points. Identify the demise from the lease plan before drawing the red line, because a garden that looks exclusive is often demised with rights rather than owned. Serve notice early and keep proof. And expect the freeholder or management company to object if they have not been consulted beforehand, which is avoidable and damaging.
Leasehold consent as a separate requirement
Planning permission does not override the lease, and this is the step that derails more flat alterations than planning does.
Most long leases prohibit structural alterations without the landlord's consent, and many prohibit any alteration to the exterior. A licence to alter is the usual mechanism, often involving the landlord's surveyor and legal costs payable by the leaseholder. Where the alteration is an improvement, statute limits the landlord's ability to withhold consent unreasonably in some circumstances, and the detail is a legal question rather than a planning one.
Add to that the Party Wall etc. Act 1996 for work to a party structure between flats, building regulations approval, and in a managed block the practical need for access and agreed working hours. None of these is a planning matter and all of them can stop the work.
Routes available when no right exists
Where the right does not exist, the options are ordinary and manageable.
- A full planning application, on the full form rather than the householder form, with a fee from the current schedule.
- A pre-application enquiry, which is usually worth the fee for a flat alteration because the council's design guidance for flats is often unwritten.
- A planning statement setting out the amenity case, since the officer's main concern will be the effect on the other flats rather than on the street.
- A design and access statement where the site is in a conservation area and the development meets the threshold, in which case a design and access statement is a validation requirement rather than an optional extra.
- A certificate of lawfulness under section 192 of the Town and Country Planning Act 1990 where you believe a particular item falls outside development altogether, such as internal works with no external effect.
Internal alterations with no external change and no change of use are generally not development at all, which is the one piece of good news in this area. Moving a kitchen within a flat is a lease and building regulations question rather than a planning one.
See which documents an application for a flat needs by browsing the report categories and starting a draft.
This is general guidance, not legal advice. A lawful development certificate is the only formal way to confirm that works are lawful, so check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
Do flats have permitted development rights?
Very few. Article 2 of the General Permitted Development Order 2015 excludes a building containing one or more flats, and a flat within such a building, from the definition of dwellinghouse. Every Part 1 householder class is drafted by reference to a dwellinghouse, so extensions, dormers, outbuildings, porches and hard surfaces all need permission.
Does a maisonette count as a house for permitted development?
No. The test is whether the building contains one or more flats, not how the unit feels to live in. A building divided horizontally into two maisonettes contains flats, so neither unit has Part 1 rights. The application also goes on the full form rather than the householder form, which changes the fee.
Can I put solar panels on a block of flats without permission?
Often yes. Several classes in the microgeneration Part of Schedule 2 are drafted by reference to a dwellinghouse or a block of flats, which is why roof-mounted solar can be permitted development on a block even though an extension is not. Read the class text, since limits on size, position and listed buildings apply.
Who has to be notified when a leaseholder applies for permission?
Anyone can apply for permission on land they do not own, but the correct ownership certificate must be used and notice served on the other owners. A freeholder is an owner for this purpose. Check the lease plan before drawing the red line, because a garden that looks exclusive is often demised with rights rather than owned.
Do I need the freeholder's consent as well as planning permission?
Usually yes, and it is a separate matter entirely. Most long leases prohibit structural or external alterations without the landlord's consent, granted through a licence to alter with the landlord's surveyor and legal costs payable by the leaseholder. The Party Wall etc. Act 1996 and building regulations also apply.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.