Kitchen extensions: A cost breakdown
Thinking about adding space, light and value to your home? A kitchen extension can transform how you live, creating room for cooking, dining and gathering in one sociable, practical zone.
A recent survey by Houzz showed that kitchens are among the most upgraded rooms, with around 26% of respondents improving this space last year; 13% of those wanted to add areas to socialise, eat and relax in their kitchen. Reports also suggest that a well-executed kitchen extension can add up to 15% to the property’s value – another good reason to consider an extension.
However, it’s necessary to understand what the kitchen extension price drivers are – from structural work, installation, and services, to flooring and tiling costs. Our guide breaks these costs down, helping you budget for your new dream kitchen.
How much does a kitchen extension cost?
An average kitchen extension in London costs from around £1,700 per m². Remember that prices vary widely with your property’s location, and the project’s scope, design complexity, and finish – everything from your area, ground conditions, and roof type to glazing, services, and structural steel can shift the budget.
It’s well worth planning your layout and storage first, as this can save costly changes later. For deeper planning advice, see our ultimate guide to kitchen planning.
Ask for a detailed quote
As always, watch out for cowboy builders who provide unrealistically cheap quotes. Not only could the work quality be poor and lack guarantees and warranties, but the costs often increase as the job progresses. Get three quotes and always ask for a detailed quote breakdown, so you can compare like for like.
The cost to knock through a wall compared with extending out
Removing an internal wall to combine your kitchen with another room without increasing the home’s footprint is often simpler and less expensive than building a new space outside the current footprint.
Knocking through
If you already have enough floor area across the chosen rooms, knocking through is a good option to bring light and spaciousness to your kitchen. Planning permission is not typically required; however, you may need to employ a Party Wall surveyor if you share a wall with your neighbours. A surveyor could cost from £90 per hour.
You can expect to pay between £1,200 and £5,000, according to one South and East of England architectural firm, to knock down an internal wall, although this depends on whether it is load-bearing. If it is, a rolled steel joist (RSJ) may have to be installed at an extra cost.
Extending out
Consider extending out if you need more square metres for a larger kitchen, utility, or generous dining/family zone, and can trade some garden for living space.
Extending your property’s footprint costs from around £1,700 per m² for a single-storey extension, and is a more complex and time-consuming project than removing an internal wall. Planning permission may be needed, though many single-storey rear extensions fall under Permitted Development, and drains could require moving or building over. A planning permission application fee is £528 currently in England.
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Kitchen installation costs – joiner vs kitchen supplier
The two most popular routes to getting your kitchen fitted are to hire an independent joiner or fitter or use the kitchen retailer’s installation service. But how much will you pay for each option?
Independent joiner or fitter
Builders often work with subcontractors, such as joiners, to keep everything moving smoothly – especially when the kitchen is part of a broader extension or renovation project. With the builder coordinating trades and sequencing, you reduce downtime and scope gaps. This approach is also the strongest choice for complex layouts and bespoke detailing, where custom cabinetry and integrated appliances benefit from a tightly managed, craft-led fit.
According to London-based FMB member Red Box, the average kitchen fitter costs around £300 a day. However, this figure varies depending on location, the fitter’s skills, expertise and the complexity of the project. Some fitters will lay flooring as part of the project, while others don’t; in such cases, flooring costs will have to be added on. As you typically buy the kitchen separately, labour often ends up being approximately 20 – 30% of the final kitchen cost.
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Retailer-managed installation
If you’re considering a stand-alone kitchen refit and want the convenience of a single provider, employing the kitchen retailer to carry out the installation may be an option. However, this frequently carries a premium price over an independent fitter.
Recent consumer guides put retailer-managed installs for a standard kitchen in the £3,000 – £4,000 bracket, scaling with size and complexity. This usually excludes installing any plumbing and electrical cabling. Also, note that the packages can vary, with some including the removal and disposal of your old units and making good, and others charging extra for these services.
The cost of tiling splashbacks
Tiling a kitchen splashback is one of the most affordable, high-impact upgrades in a renovation, but prices do vary with the size of the area, the complexity of the design, and the required preparation.
Tiling a splashback costs from around £30 per m², but expect higher quotes for herringbone designs or lots of socket cut-outs. For small, simple splashback projects, professional tilers may quote a fixed ‘minor works’ price, rather than a strict price per metre.
Kitchen extension costs for flooring
As with all kitchen installation costs, any figures for fitting the flooring depend on your location, the size of the area requiring flooring, the complexity of the design, and the flooring material chosen.
Vinyl flooring is typically the cheapest labour option, with costs rising from under £20 per m², tiled floors from £50 per m², and laminate fitting from £60 per m².
Costs for moving a boiler
As part of your kitchen extension project, you may need to move your boiler. Relocating can be a complex job that includes installing new gas pipes and drilling a new flue. This all takes time – typically, half a day for a simple move. Expect to pay from around £200 for a straightforward relocation.
A Gas Safe-registered engineer must carry out any boiler work.
Budgeting for fitting new kitchen appliances
The labour costs for fitting any new appliances you want are often an afterthought; however, these prices all add up and should be considered from the start.
Any quotes are dependent on hardwiring, pipework changes, and cabinetry adjustments, with a simple freestanding washing machine connection costing from £30, rising to around £120 for an integrated model. Oven installations generally range from £100 to around £125, depending on whether you choose gas or electric, while an integrated fridge-freezer can cost up to £115.
Hidden costs
There are always going to be extra items to budget for – scaffolding, skip hire, and even setting up a temporary kitchen, for example, so remember to include these.
You’ll also need to consider the cost of decorating your finished kitchen, which is where the fun begins!
Ready to get started with your kitchen extension?
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