Flat Conversions Kensington

Flat conversion in Kensington works on a small pool of houses. Across the VOA statistical areas of Kensington Abingdon and Kensington Gardens, 15% of homes are houses and 85% are already flats. Splitting one of the remaining townhouses into self-contained flats needs planning permission and must meet the space standards, and joining flats back into one home runs against local housing policy. We build conversions to the approved drawings, with fire separation, acoustic floors and room sizes settled on paper before the first stud goes up.

In Kensington, converting a house into two or three flats is published at £50,000 to £120,000 including professional and council fees, and an England-wide guide puts a straightforward two-flat split at £40,000 to £80,000 in construction alone, which is the part a builder prices (indicative London ranges, Architectural Drawings and Mayfair Studio, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Kensington: we build the conversion to the approved drawings, building control inspects the fire and sound separation, and a registered electrician certifies each flat's electrics.

Why merging Kensington flats back into a house is resisted

Reuniting a divided Kensington house is something buyers ask about, and the local plan stands in its way. Policy HO1 in the publication version of the New Local Plan Review, which the national Planning Data record lists as adopted with a start date of 24 July 2024, protects existing market homes and rules out merging self-contained Class C3 flats. A buyer who hopes to join two floors of a split stucco house into one home should take planning advice before exchange, because it can change what the purchase is worth to them.

What stays open is improving each flat inside its own boundary: a better plan, new bathrooms, a reworked kitchen and stronger separation from the neighbours. That is building work we can price from your designer's plans. Where a Kensington scheme does alter the number of homes, the planning drawings fix the unit count and we build to it exactly, since a change made on site can put the consent at risk.

Housing in Kensington

The valuation list shows roughly 9,000 homes in Kensington, of which 75% are pre-1919, 6% interwar and 19% post-1945, split 85% flats to 15% houses. Where most homes are flats, a flat in Kensington can be split or combined only with the freeholder's consent, and changing the number of homes usually needs planning permission as well.

Room sizes and heights for a new Kensington flat

Each new Kensington flat must be sized to the national space standards, which policy HO4 in the New Local Plan Review applies to every new home. The London Plan, through Policy D6, goes into detail: a single bedroom for one person needs a floor area of at least 7.5 square metres and a width of at least 2.15m. Headroom counts too, with 2.5m from floor to ceiling required over at least 75 per cent of each flat's internal area. The London Plan table counts conversions and changes of use as new dwellings.

On the main floors of a Kensington period house the height is rarely an issue, but the lower ground and the top storey can fall short. The borough's plan also says that where two bedroom homes are provided they should be for four people, so that young families can live there. Those numbers pin down where partitions go, so we mark every wall out on the floor from the drawings and measure each room before a board is fixed.

Services, addresses and party walls when a Kensington house is split

Every flat carved out of a house needs its own supplies, and planning those runs is half the job. In a Kensington terrace the new risers for water, drainage, electricity and gas have to find a route up the house without breaking the fire separation between flats. Each flat gets its own consumer unit and meter, a separate gas supply or an all electric design, and a stack or branch for its bathroom and kitchen. The utilities need the new addresses before they will connect.

Those addresses come from the council's street naming and numbering service, which the owner or their agent applies to once the flats are defined. The neighbours come into it too. Where the conversion cuts into a party wall for new steels or fire linings, or builds on the line of junction, the Party Wall Act applies, and the building owner serves the notices before that work starts. We programme those items early, since late meters or a party wall award can hold up completion.

Fire and sound separation between Kensington flats

Separating Kensington flats to a proper standard means upgrading old joisted floors and stud walls, not just boarding over them. For flats formed by a material change of use, Approved Document E sets 43 dB of airborne sound insulation through separating walls and floors, and impact sound through floors no higher than 64 dB. Lath and plaster under bare joists is unlikely to reach that, so the floor build up is designed before strip out.

Fire separation under Part B follows the same pattern: a protected escape route, a fire door to each flat, and fire stopping wherever pipes and cables cross a separating floor. In a Kensington townhouse the stair is usually the escape route for every flat above the ground floor, so it is enclosed in fire resisting construction from the lower ground to the top storey. Any new stair also has to meet Part K, and renewed walls, roofs and windows bring in Part L.

• House to flat conversions into two or more self-contained units
• Splitting a large flat in two, or joining two flats into one
• A kitchen and shower room fitted in every new flat

VOA Council Tax stock of properties, March 2025, for Kensington Abingdon and Kensington Gardens. Counts rounded by the VOA.

If you are weighing up options for your Kensington property, it is worth reading structural alterations in Kensington, flat conversions across Kensington and Chelsea, building control sign-off for a conversion, the Party Wall Act when a conversion cuts a shared wall, flat conversions anywhere in London and How to Choose a Builder.

The GS Renovation Difference in Kensington

Conversions go wrong at the junctions: floors that fail a sound test, fire stopping missed behind a ceiling, a room built short of its approved size. We set out from the approved drawings, check room dimensions before boarding, and keep building control inspections in step with the separating floors and walls. The owner or their designer handles planning and street naming; we build to the consent and supply the drawings, programme and completion records they need.

• Free, no-obligation quotations
• Wet rooms stacked floor over floor to keep the drainage simple
• Separating floors built to the acoustic detail the sound test checks

Checked by Abdelaaziz Saaid, founder and director of GS Renovation Ltd (Companies House no. 14611254). Structural design is by the consulting engineer appointed to your project.