Permitted Development Rights for Flats in London: A Practical Guide

Introduction

Permitted development rights are a common source of confusion for flat owners in London. While houses benefit from a wide range of permitted development rights — allowing rear extensions, loft conversions, outbuildings and other works without planning permission — the permitted development rights available to flats are significantly more limited. Understanding what you can and cannot do without planning permission is essential before beginning any works on a London flat.

What Permitted Development Rights Apply to Flats?

The Town and Country Planning (General Permitted Development) (England) Order 2015 (GPDO) is the statutory instrument that establishes permitted development rights. The key limitation for flats is that most of the householder permitted development rights under Schedule 2, Part 1 (development within the curtilage of a dwellinghouse) explicitly do not apply to flats — the definition of "dwellinghouse" in planning law excludes a flat.

This means that the most common householder PD rights — single-storey rear extensions, loft conversions, outbuildings, porches — are not available for flats. Any such works to a flat require planning permission.

What Permitted Development Rights Do Apply to Flats?

While flats cannot use the householder PD rights in Part 1, they do benefit from some other PD provisions:

• Satellite dishes: Under Part 16 (Permitted development by electronic communications networks operators), some satellite dishes can be installed on flats under deemed consent, subject to size and position conditions. However, in conservation areas, Article 4 Directions typically remove this right.
• Internal works: Works entirely within the interior of a flat that do not affect the external appearance of the building or structural elements do not require planning permission. This includes kitchen and bathroom refurbishments, internal decoration and minor non-structural internal alterations. However, listed building consent may be required for works to a listed building.
• Change of use: Certain changes of use are available under Part 3 of the GPDO, including changes between some use classes, though these are primarily commercial rather than residential in nature.

Extensions and Alterations to Flats

Any external alteration to a flat — including rear extensions, loft conversions, dormer windows, replacement windows or doors, external cladding — requires planning permission. This applies regardless of whether the flat is in a purpose-built block or a converted Victorian or Edwardian terrace.

In conservation areas with Article 4 Directions, even works that might be permitted development elsewhere (such as satellite dishes or certain roof alterations) require planning permission.

Loft Conversions in Mansion Flats and Period Buildings

Loft conversions in purpose-built Victorian mansion flat blocks are a particular case. Where a flat owns the loft space above it (either by lease or freehold), adding a loft conversion typically requires:

• Planning permission (as it is an external alteration to the building)
• Consent from the freeholder or management company (as it affects common parts or the building structure)
• Party wall notifications if the works affect shared party walls or floors with adjacent flats
• Listed building consent if the building is listed

This makes loft conversions in converted period buildings or mansion flats significantly more complex and uncertain than loft conversions in houses.

First Floor Flat with Ground Floor Extension

First floor flat owners sometimes consider extending at ground level into the garden. This is not possible under permitted development for a flat, and even with planning permission, ground floor extension rights are typically vested in the ground floor flat or the freeholder, not the first floor flat. Lease agreements will almost always require freeholder consent for any physical extension, and the planning position must be confirmed independently.

Upper Floor Additions in Converted Victorian Houses

In a converted Victorian terrace house (where the building has been divided into flats), the upper floors may be separate flats but the building as a whole is typically subject to a single planning permission. External alterations — including rear dormers, roof alterations, side infills — relate to the whole building rather than any individual flat. Planning permission is required for any such alterations, regardless of which flat owner proposes them, and the works must typically be carried out by or with the consent of the freeholder who controls the whole building.

Article 4 Directions and Flats

In conservation areas with Article 4 Directions, the Directions apply to all residential properties within the designated area — including flats. The effect is to remove any remaining permitted development rights that would otherwise apply, ensuring that all external works (satellite dishes, aerials, minor roof alterations) require planning permission.

Conclusion

Flat owners in London have significantly more limited permitted development rights than house owners. Any external alteration or extension to a flat requires planning permission, regardless of the scale of the works. For flat owners in conservation areas, Article 4 Directions further restrict what can be done without consent. Working with an architect who understands the specific planning framework for flats in the relevant London borough — and who understands the leasehold/freehold implications of any proposed works — is essential before committing to any alteration project.