A kitchen extension is one of the most popular projects we build across Ealing and West London, and one of the first questions every homeowner asks is what it will actually cost. The honest answer is that it depends on size, specification and the state of your existing house, but there are sensible ranges you can plan around. This guide breaks down realistic figures for 2026 and the costs people most often forget.
In West London, most single storey rear kitchen extensions come in between £2,500 and £3,500 per square metre for the build itself, before the kitchen is fitted. A modest 15 square metre extension therefore tends to land somewhere between £40,000 and £55,000 for the shell and finishes, while a larger 25 to 30 square metre wraparound on a Victorian terrace can reach £75,000 to £100,000 or more once glazing and steelwork are included.
London sits noticeably above national averages because of labour rates, access constraints on terraced streets and the age of the housing stock. Ealing's Victorian and Edwardian homes often need underpinning checks, party wall agreements and drainage diversions that a newer property elsewhere would not.
The build cost is only part of the picture. A mid range fitted kitchen with appliances typically adds £12,000 to £25,000, while bespoke cabinetry with stone worktops can comfortably exceed £40,000. It is worth deciding your kitchen budget early, because the position of islands, extraction and appliances affects where we run services during the build, and moving them later is expensive.
Glazing is the other big variable. Standard bifold or sliding doors might cost £8,000 to £15,000 fitted, but slim frame sliding systems and large rooflights can double that. Many of our Ealing clients spend more on glazing than they first expected because it does so much of the work in making the space feel bright.
Beyond the headline build price, allow for professional fees and statutory costs. Architectural drawings, structural engineering calculations and building control fees usually total £4,000 to £8,000. If your extension goes within three metres of a neighbour's structure, the Party Wall Act applies, and surveyor fees can add £1,000 to £2,500 per adjoining owner.
VAT at 20 percent applies to most extension work, so check whether quotes include it. You should also hold a contingency of around 10 to 15 percent, particularly on older properties where opening up walls can reveal surprises such as shallow foundations or outdated wiring that must be brought up to standard.
The biggest savings come from decisions made before anyone picks up a shovel. Keeping the extension within permitted development rules avoids a full planning application, keeping drainage and structural spans simple reduces steelwork, and choosing a rooflight over a full glass roof can save five figures without losing much light.
Get itemised quotes rather than a single lump sum, so you can see exactly what is and is not included. A quote that looks cheap often excludes the kitchen fit out, decoration, flooring or VAT. A detailed, fixed price quotation based on proper drawings protects you far better than a low estimate based on a quick site visit.
In most West London postcodes a well built extension adds meaningful value, often recovering a large share of its cost, but the bigger return for most families is usable space. Treat added value as a bonus rather than the main justification.
Many single storey rear extensions fall under permitted development, meaning no full application is needed, though a lawful development certificate is strongly advised. Wraparounds, flats and homes in conservation areas usually need planning permission.
A typical single storey kitchen extension takes 12 to 16 weeks on site, plus the kitchen fit out. Allow another two to four months beforehand for design, approvals and party wall matters.
Tell us about the house and what you are planning. A quick chat with Steve is usually enough to point you the right way.