Two-storey rear extension in Kensington and Chelsea

Where in Kensington and Chelsea does a two storey rear actually get determined?

Every Kensington and Chelsea postcode district we draw in, the stock that dominates it and the authority that validates a two storey rear there. Kensington and Chelsea fees below are the statutory England rates for 2026, not two storey rear estimates.

How does a two storey rear differ street by street across Kensington and Chelsea?

Roof pitch, wall build-up and plot depth change every few Kensington and Chelsea streets, and each one changes what a two storey rear can achieve at that address.

• Kensington (W8) — Georgian and Victorian stucco terraces defines Kensington, where stucco terraces, listed buildings set what a two storey rear can do. The side-return infill is the classic move on these Victorian terraces — 3 m of permitted development depth plus the width of the original side passage across W8. Any Kensington two storey rear is validated by RBKC Planning, with Kensington Palace the usual Kensington reference point on the site plan.
• Chelsea (SW3, SW10) — a two storey rear in Chelsea starts from georgian and victorian terraces, listed buildings, and Chelsea reads as Georgian and Victorian terraces, riverside. Georgian rear elevations here are usually the listed or locally listed face of the building in SW3. RBKC Planning assesses Chelsea two storey rears against its own Chelsea character guidance, and the location plan we draw for Chelsea references King's Road.
• Notting Hill (W11) — stucco terraces, painted facades defines Notting Hill, where victorian stucco terraces set what a two storey rear can do. The side-return infill is the classic move on these Victorian terraces — 3 m of permitted development depth plus the width of the original side passage across W11. Any Notting Hill two storey rear is validated by RBKC Planning, with Portobello Road the usual Notting Hill reference point on the site plan.
• Holland Park (W11, W14) — a two storey rear in Holland Park starts from victorian and edwardian villas, and Holland Park reads as Victorian villas around the park. The side-return infill is the classic move on these Victorian terraces — 3 m of permitted development depth plus the width of the original side passage in W11. RBKC Planning assesses Holland Park two storey rears against its own Holland Park character guidance, and the location plan we draw for Holland Park references Holland Park.
• Earl's Court (SW5) — two storey rear work in Earl's Court means stucco terraces, edwardian mansion blocks. Earl's Court is Victorian stucco terraces, mansion blocks. Edwardian plots here are wider throughout SW5. RBKC Planning decides the Earl's Court application, and Earl's Court station anchors the Earl's Court location plan.
• South Kensington (SW7) — a two storey rear in South Kensington starts from stucco terraces, mansion blocks, listed buildings, and South Kensington reads as Victorian and Edwardian stucco terraces. Ground-floor mansion-block flats can extend into a rear light well in SW7. RBKC Planning assesses South Kensington two storey rears against its own South Kensington character guidance, and the location plan we draw for South Kensington references V&A.
• Knightsbridge (SW1X, SW7) — Regency and Victorian terraces, luxury defines Knightsbridge, where regency and victorian terraces, mansion blocks set what a two storey rear can do. The side-return infill is the classic move on these Victorian terraces — 3 m of permitted development depth plus the width of the original side passage across SW1X. Any Knightsbridge two storey rear is validated by RBKC Planning, with Harrods the usual Knightsbridge reference point on the site plan.

Does Kensington and Chelsea planning policy restrict a two storey rear?

Kensington and Chelsea conservation designations: there are 38 across RBKC Planning, Chelsea, Notting Hill, Holland Park among them. Designation costs a Kensington and Chelsea owner the permitted-development route: a two storey rear then needs a £548 householder application over 8 weeks, in place of the £249 prior approval route that takes 6 weeks. Chelsea is the Kensington and Chelsea designation that most often changes a two storey rear design.

Kensington and Chelsea and Article 4: Article 4 Directions covering HMOs, office-to-residential, and basement developments — RBKC has some of the strictest basement policies in London. A two storey rear planned at a SW3 address is checked against that direction first; RBKC Planning publishes the Kensington and Chelsea extent, and the SW3 line rarely follows the Kensington and Chelsea boundary you would expect.

Kensington and Chelsea below-ground policy: RBKC's basement policy (post-2015) limits to single-storey under 50% of garden area; double-storey basements effectively prohibited in residential streets. Any two storey rear in Kensington and Chelsea that goes below existing foundations triggers two months notice under section 6 of the Party Wall etc. Act 1996, and RBKC Planning will want the SW3 ground and groundwater position set out.

The building fabric around Kensington and Chelsea: Grand white stucco Regency and Victorian terraces; red-brick Queen Anne mansions in Kensington; Edwardian mansion blocks; almost no post-war housing stock. Internationally wealthy residents; extensive listed building coverage; heritage and streetscape prioritised in every decision. A two storey rear in Kensington and Chelsea is scoped against that stock first.

Which neighbouring authorities border Kensington and Chelsea?

• Westminster — cross the Kensington and Chelsea boundary and Westminster City Council takes the two storey rear instead, applying 56 conservation areas of its own around SW1. We re-price two storey rears at the Kensington and Chelsea edge because Westminster policy and Kensington and Chelsea policy rarely align on two storey rear depth.
• Hammersmith and Fulham — cross the Kensington and Chelsea boundary and Hammersmith & Fulham Council takes the two storey rear instead, applying 45 conservation areas of its own around W6. We re-price two storey rears at the Kensington and Chelsea edge because Hammersmith and Fulham policy and Kensington and Chelsea policy rarely align on two storey rear depth.
• Brent — the Brent boundary runs against Kensington and Chelsea, so a two storey rear a street from Kensington and Chelsea is decided by Brent Council instead. Brent runs 22 conservation areas across NW2 and its neighbours, which is why two storey rears priced for Kensington and Chelsea are re-checked against Brent policy whenever the Kensington and Chelsea address sits on that edge.

Sources for this Kensington and Chelsea two storey rear page: borough policies maps and conservation-area registers (2025–26), Royal Mail postcode district boundaries, the Town and Country Planning (Fees for Applications) (England) Regulations, the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended, and the Party Wall etc. Act 1996.