Kitchen Extension Cost London 2026: Complete Price Guide by Size and Type

A kitchen extension is one of the most popular home improvements in London — it creates a large, light-filled open plan kitchen, dining and living space that dramatically improves how you use your home and delivers exceptional value uplift. Kitchen extensions can be built as rear extensions, side returns, wraparound extensions or double storey extensions depending on your property. This guide gives you accurate 2026 kitchen extension costs across all four types so you can budget realistically before starting your project. LCCL Construction has delivered hundreds of kitchen extensions across London and Hertfordshire.

LCCL Construction — specialist kitchen extension builders across London

How Much Does a Kitchen Extension Cost in London in 2026?

Kitchen extensions in London cost between £35,000 and £128,000 in 2026 depending on the type and size of extension. The average project cost is £66,000 – £102,000 inc. VAT (£55,000 – £85,000 + VAT) for a typical Victorian or Edwardian terrace kitchen extension. This includes architectural design, planning permission where required, building regulations, structural calculations, party wall notices and all construction works. The kitchen itself — units, worktops, sink and fitting — can be added to the same contract, priced by size and specification; appliances are supplied by the client.

Kitchen Extension Cost by Type in London

Rear kitchen extension: £42,000 – £153,600 inc. VAT (£35,000 – £128,000 + VAT). Extends the kitchen straight out into the garden — the classic approach. See our full rear extension cost guide.

Side return kitchen extension: £42,000 – £153,600 inc. VAT (£35,000 – £128,000 + VAT). Fills the narrow side alley alongside a Victorian or Edwardian terrace kitchen. See our full side return cost guide.

Wraparound kitchen extension: £42,000 – £153,600 inc. VAT (£35,000 – £128,000 + VAT). Combines rear and side return for the largest open plan kitchen space possible. See our full wraparound cost guide.

Double storey kitchen extension: £90,000 – £198,000 inc. VAT (£75,000 – £165,000 + VAT). Adds kitchen space downstairs plus bedrooms or study upstairs. See our full double storey cost guide.

What Affects Kitchen Extension Cost in London?

The main factors are: size in square metres, type of extension, structural complexity of removing existing kitchen walls, specification of glazing including bifold doors sliding doors and roof lanterns, quality of internal finishes, planning permission requirements and location within London. The final figure depends on postcode, access and site conditions — the instant estimate applies your area.

What Is Included in a Kitchen Extension Cost?

LCCL Construction kitchen extension costs include: measured building survey, architectural design, planning permission application, building regulations, structural engineer calculations, party wall notices, groundworks and foundations, steelwork to remove existing kitchen walls, superstructure, roof, external brickwork or render, bifolds or sliding doors, first fix electrics and plumbing including new kitchen supply and waste points, insulation, plastering, second fix and decoration. Kitchen units, appliances, worktops and splashbacks are typically supplied and installed by the client's kitchen supplier on second fix.

Should I Include the Kitchen Units in My Budget?

Yes — the kitchen itself is priced on top of the extension build. A new kitchen supplied and fitted by LCCL (units, worktops, sink and tap, fitting and connections to existing services) costs £9,000 – £31,200 inc. VAT (£7,500 – £26,000 + VAT) at economy specification depending on size — from small (up to 8 units) to extra large (17+ units with an island) — £16,200 – £56,160 inc. VAT (£13,500 – £46,800 + VAT) at mid-range, and £25,200 – £87,360 inc. VAT (£21,000 – £72,800 + VAT) at high-end. Appliances, flooring and tiling are extra, and every figure is subject to the final design, site measurements and the kitchen range you choose.

How Much Value Does a Kitchen Extension Add?

On our projects and local sold prices, a well-planned project of this kind usually adds more to the value of the home than it costs to build — see our guide on how much value an extension adds. A £65,000 kitchen extension typically adds £115,000 to £195,000 in outer London and £180,000 to £320,000+ in premium locations. Kitchen extensions deliver exceptional returns because the kitchen is the highest-value room in the modern home. See our full guide on how much value an extension adds.

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 a planning application? Check if you need planning permission

Frequently Asked Questions About Kitchen Extension Cost in London

How much does a kitchen extension cost in London?

From £42,000 inc. VAT (£35,000 + VAT) for a small rear or side return to £128,000 for a large wraparound with premium specification.

How long does a kitchen extension take?

Typically 12 to 16 weeks on site for a single storey, 18 to 24 weeks for a double storey. Design and planning add another 12 to 16 weeks upfront.

Does the extension builder install the kitchen?

Yes — LCCL supplies and fits new kitchens and kitchen refits under the same contract as the extension, priced by size and specification (economy, mid-range or high-end). Appliances, flooring and tiling are quoted separately.

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