House Extensions Kensington W8 2026: Complete Guide to Costs, Planning and Design

Kensington is one of London's most prestigious and architecturally magnificent residential areas, home to Kensington Palace, Hyde Park, world-class museums and some of the finest Victorian and Georgian terraced houses and stucco-fronted properties in the capital. The W8 postcode encompasses Kensington proper, Holland Park, Campden Hill and Notting Hill Gate — all characterised by exceptional Victorian and Edwardian houses with some of the highest property values in London. A house extension in Kensington W8 represents one of the strongest returns on investment of any London location. LCCL Construction delivers house extensions across Kensington and all of West and Central London as part of our complete design and build service.

LCCL Construction — specialist house extension builders in Kensington W8 and West London

Not sure whether your project needs planning permission? Enter your postcode and tick what you want to build — we look up the conservation areas, Article 4 directions and listed buildings for you, and you see which parts are permitted development and the from-price for each. Lawful Development Certificate included on every permitted development job.

Planning check

House Extensions Kensington W8: Best Types for Local Properties

Kensington's Victorian terraced and semi-detached houses suit rear extensions, side return extensions and wraparound extensions. The side return extension is particularly popular in W8 — filling the narrow side alley to create a dramatically wider ground floor. Given Kensington's exceptional property values every well-designed extension generates outstanding returns.

How Much Do House Extensions Cost in Kensington in 2026?

Rear extension: £42,000 – £90,000 inc. VAT (£35,000 – £75,000 + VAT).

Side return: £42,000 – £93,600 inc. VAT (£35,000 – £78,000 + VAT).

Wraparound: £72,000 – £153,600 inc. VAT (£60,000 – £128,000 + VAT).

Double storey: £90,000 – £198,000 inc. VAT (£75,000 – £165,000 + VAT).

All include full design and build. See our full house extension cost guide.

Planning Permission for House Extensions in Kensington W8

Planning in Kensington is among the most complex in London. The Royal Borough of Kensington and Chelsea covers W8 and applies some of the strictest design guidelines of any London borough. Much of the area falls within conservation areas — including the Kensington Conservation Area and the Holland Park Conservation Area — where planning permission is always required. LCCL Construction manages all planning applications. See our guide to house extension planning permission.

How Much Value Does a House Extension Add in Kensington?

Kensington properties regularly achieve £2,000,000 to £8,000,000+. A wraparound extension costing £72,000 – £153,600 inc. VAT (£60,000 – £128,000 + VAT) can add £300,000 to £600,000 in value — a return of 280 to 500 per cent. See our guide on how much value an extension adds in London.

Areas Around Kensington We Cover

LCCL Construction covers Kensington W8, Holland Park W11 W14, Notting Hill W11, Chelsea SW3, South Kensington SW7, Earl's Court SW5, Fulham SW6, Hammersmith W6, Shepherd's Bush W12, Bayswater W2 and all surrounding West London postcodes.

Can it be done under permitted development?

A single-storey rear extension of 3 m on a terrace or semi (4 m on a detached house), a side-return infill and a side extension up to half the original width are permitted development on a house outside a conservation area or Article 4 street — no planning application, just a Lawful Development Certificate, which we apply for on every one. Fixed-price permitted development extensions start from £42,000 inc. VAT (£35,000 + VAT) at economy specification, design and build inclusive, and the 6 m / 8 m larger home extension goes through a 42-day prior approval notification rather than a full application. See our permitted development projects page for every product with its from-price and the checks we run before we confirm a project qualifies.

Not sure whether your project needs planning permission? Enter your postcode and tick what you want to build — we look up the conservation areas, Article 4 directions and listed buildings for you, and you see which parts are permitted development and the from-price for each. Lawful Development Certificate included on every permitted development job.

Planning check

Frequently Asked Questions About House Extensions in Kensington

How much does a house extension cost in Kensington W8?

Costs range from £57,600 inc. VAT (£48,000 + VAT) for a small rear extension to £175,000 for a large double storey. A wraparound extension typically costs £72,000 – £153,600 inc. VAT (£60,000 – £128,000 + VAT).

Do I need planning permission for a house extension in Kensington?

Yes — most extensions in W8 require planning permission due to conservation area coverage and RBKC's strict design policies.

To get a free consultation call LCCL Construction on 020 8037 7332 or get an instant quote online.