Flat Conversion Drawings in London | Fixed Fee

Do I need planning permission to convert a house into flats?

Yes, always. Converting a single dwelling into two or more self-contained flats is a change from one home to several, and that subdivision is treated as development requiring a full planning application — there is no permitted development route that allows it, regardless of the property's size or whether the exterior changes at all. The application has to demonstrate that each flat meets space, layout, amenity and parking standards in its own right, not just that the building as a whole is being used sensibly.

Boroughs also weigh the loss of a family-sized house against their local housing policy, since converting a larger house into several flats reduces the stock of homes suited to families even as it adds smaller units. We take that policy context into account when advising on layout and unit numbers, rather than simply maximising the number of flats the floor area could technically support.

What sound insulation is required between flats?

Part E of the building regulations sets minimum sound insulation standards for the walls and floors separating flats, covering both airborne and impact sound. Where an existing house is subdivided, the drawings specify how the party floors and walls between units will be upgraded — additional layers, resilient bars, or a floating floor — and pre-completion sound testing is normally required before the flats can be signed off. Getting this detail right on the drawings from the outset matters, because retrofitting sound insulation after a failed test usually means taking up a finished floor or ceiling that has already been decorated.

How do you design fire escape and compartmentation for flat conversions?

Each flat needs its own independent means of escape to a place of safety, and the building has to be compartmented so that fire in one flat does not spread into another or into the shared circulation space. On a typical converted house this means fire-rated floors, walls and doors between units, and either a protected common stairway shared by the flats or separate final exits for each one, depending on the layout.

Where flats sit above ground floor level, escape routes and fire doors are designed together with the sound insulation upgrade, since the same floor and wall build-ups often need to satisfy both requirements at once.

Does each flat need its own entrance and services?

Each self-contained flat needs independent services — its own kitchen, bathroom, heating and, in almost all cases, its own gas, electricity and water metering — so residents can be billed separately and one flat's use does not depend on another. Entrances can either be genuinely separate front doors or a shared communal entrance leading to individual flat doors off a common hallway; either arrangement can work, but the drawings need to show clearly which one is proposed and how it affects escape routes and postal or refuse arrangements. Bin and cycle storage for each flat also has to be shown on the drawings, since a scheme with nowhere sensible to put bins for two or three separate households is a common and avoidable reason for a planning officer to raise concerns.

What are the minimum floor areas for flats in London?

London applies minimum internal floor areas to new flats, based on the number of bedrooms and the number of people the flat is designed for, as part of the London Plan's adoption of the national space standards. A proposed layout that falls below the relevant minimum is a common reason for refusal, so we check each flat's floor area against the applicable threshold at the layout stage, before the drawings go anywhere near the council. Storage space, outlook and access to daylight are assessed alongside floor area, since a flat that technically meets the minimum square metreage can still be refused if it has no useful storage or a poor outlook, so we treat these as a single design problem rather than a box-ticking exercise once the floor area passes.