Flats · Planning
Converting a House into Flats in London: The Planning Position
Subdividing a house into flats — or combining flats back into a house — always requires full planning permission in England. This guide explains why, what London boroughs assess, and the building regulations and consents that come with it.
The short answer
Converting a single house into two or more flats always requires full planning permission in England. It is not permitted development, and it is not a householder application — because it changes the number of homes, it is a full planning matter the local authority assesses on its merits. Combining flats back into a single home (amalgamation) can also need permission, though that depends on how the authority views the loss of separate homes.
Why permission is always required
Creating an additional dwelling is a material change the planning system controls in every case; there is no permitted development right to subdivide a house into flats. Because it is not a householder application, the wider planning tests apply, and the proposal is judged against the borough’s housing and design policies rather than the narrower householder rules. It is also why requirements such as Biodiversity Net Gain can be engaged, where a householder extension would be exempt.
What London boroughs weigh
Boroughs assess a conversion against the quality of the homes it creates and its effect on the area. Typical considerations include the size and standard of each proposed flat against space standards, light and outlook, refuse and cycle storage, noise and privacy between units, parking and pressure on the street, and the external changes needed — new entrances, bin stores or window alterations — especially in a conservation area. Policies vary between boroughs, and some prime-London areas resist the loss of larger family homes, so the local plan position is worth establishing early.
Building regulations, leasehold and heritage
Planning is only one of the approvals. A conversion must meet building regulations — for fire separation between flats, sound insulation, means of escape and more — which is a significant part of the work. If the building is listed, listed building consent is likely to be required as well as planning permission. And where flats are involved, leasehold and freeholder consents, and party wall procedures between units, usually come into play. These strands are best coordinated together from the outset rather than discovered in sequence.
Frequently asked questions
Do I need planning permission to convert a house into flats?
Is converting a house into flats permitted development?
Do building regulations apply to a flat conversion?
What if the house is listed?
Do I need permission to combine two flats into one?
Is a flat conversion a householder application?
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