How Much a Kitchen Extension Costs in London

A new kitchen
February 7, 2024

A kitchen extension opens up what has now become the ‘heart of the home,’ giving you more room to cook, entertain and live. But it also adds value to your home, making it a profitable move for when you come to sell and move on.

Side and back kitchen extensions are extremely popular in London where space is at a premium.

Many families are remortgaging to pay for the extension using existing equity in their property. Others are using savings. Read on to find out the cost of a typical home extension in the UK, and what you need to know before going ahead.

Average Costs for a Kitchen Extension in London

Costs vary depending on the materials you’ll use, the size of the area you intend to build, and what type of extension you’d like. The average cost for a kitchen extension in London is £50,000 with a range of between £30,000 to £70,000.

It’s mostly the additional charges for labour that put up the price for an extension in London compared to the rest of the UK.

Most tradesmen will give a cost per square metre. This is often within the range of £1500 per square metre to £3000 per square metre. A small extension is around 15 metres squared, and a larger version can be 48 metres squared).

An average-sized kitchen extension comes in at around 24 metres squared and can take up to three months to complete.

Costs by Type of Extension

A single-storey ground floor extension would usually be at the rear of a property, but not always. It could, for instance, be at the side of your property or both ie a wraparound extension. Then again, it’s also possible – and much costlier – to have a double-storey extension built.

Clean conservatory windows as seen from the garden

Single Storey Kitchen Extension

A typical (ie not high-end) rear extension, built by a small company, and measuring around 30 metres squared will cost an average of £30,000 with a range of £20,000 to £50,000.

The same ground floor extension, built by an individual, with a high-end finish could have an average cost more in the £45,000 to £50,000 region.

Double Storey Kitchen Extension

A double storey home extension requires scaffolding, instantly adding to the cost. These are also much more complicated to design and construct. But, on the plus side, they can not only extend the size of your kitchen and living area, but also add bedrooms to your home. As a result, a double storey extension is far more expensive.

These are average costs for a typical (ie not high end) double storey extension, measuring 45 metres squared and fitted by an average-priced contractor would be £50,000 to £70,000

Side Return Kitchen Extension

Side return extensions are particularly popular amongst owners of Victorian properties as they are a great way to introduce more light into the back of the home.

A typical (ie not high-end) side return kitchen extension, built by a small company, and measuring around 30m2 would cost around £50,000 to £70,000

The same extension, built by an individual, with a high-end finish would cost around £75,000 in London.

Wraparound Kitchen Extension

Wraparound kitchen extensions give you the best of both worlds ie a rear extension combined with a side extension. It adds a lot more space to the home, making it ideal for a growing family. As a result of the extra living space though, you can expect to pay quite a bit more for your new addition.

The average costs for a typical (ie not high-end) wraparound extension, built by an average-priced company would be £70,000 to £100,000.

Kitchen Conservatory

A kitchen conservatory costs less than an extension since it takes less time to make and is actually often constructed off-site. It can form a large kitchen and dining space. The difference between conservatories and extensions is that the former tends to let in more light, since it comprises mainly of windows, with a composite roof.

Costs Breakdown

There are a number of costs involved in the building of a kitchen extension. As well as the labour costs, there are the materials to think of and the installation of electricity, gas and water.

And that’s just for starters. You’ll also have to pay for your architect’s design of the home extension (this often works out at around 10 per cent of the cost of the building) and any surveys or permits necessary.

Labour Costs

You’re looking at paying a number of different skilled tradesmen to help with installing your kitchen. Trade professionals will vary in their charges. But the following is a rough estimate of costs:

A carpenter or joiner will help with wood cladding or hardwood floors. The rate for each is around £130 to £180 a day.

Your bi-folding or sliding doors and skylights will usually be fitted by a skilled glazier. This usually comes in at around £110 to £170 per day.

A plasterer will smooth out the walls and ceilings on your extension, as well as render the exterior. For their services, you’ll pay around £100 to £170 per day.

You’ll certainly require a roof for your extension. This is constructed by a roofing professional. He or she will normally charge anything from £145 to £225 per day.

Unless you’re planning on getting out the paintbrush yourself to save money, you’ll be getting in a professional to do this aspect of the job. A painter and decorator can come in at from £100 to £190 per day on average.

Material Costs

You can get materials for a basic kitchen extension from around £19,000. If you’re looking for a high-end finish then you could pay more than twice this, at around £48,000.


You will no doubt require electrical work to be carried out in your home extension. That’s because there will be new sockets and lights that have to be wired in. And that’s where an electrician comes in. For the services of such a professional, you’ll pay anything from around £120 a day all the way up to £350 for a leading professional in London.


Once your new kitchen is built you’ll need the appliances plumbed in and a working water supply set up. This means connecting the water to the pipework and drainage systems.

For a plumber, you’ll pay from £120 to £250 per day.

New Kitchen Costs

The cost of a new kitchen depends on the quality of the cabinets, worktops and appliances that you’re looking for. Basic cabinets cost from £3,500, for instance, while luxury cabinets come in at around £5,100. You’ll then have to pay for a kitchen fitter. He or she will charge anything from £125 to £160 per day.

Fixtures and Fittings

You’ll no doubt require new light fittings for your new kitchen extension. For these, you can expect to pay from £100 to £300, depending on just how much you want to invest in this part of your décor.


The construction of your home extension may involve scaffolding, especially when it comes to installing the roofing and a Velux window or two. This normally works out at around £625 a week for a single scaffold of up to 10m high.

Skip Hire

You’ll usually need to hire skips and get a permit for them if they’re going to be on the road. A builder’s six to eight-yard skip comes in at an average cost of £220 to £410 a week.

Rental costs

The kitchen is an important part of the home to the extent it’s difficult to function without it. Not only that, but having an extension built can result in a lot of dirt and mess which you definitely don’t want trailed around the rest of the house. For these reasons many homeowners opt to rent a property for a few months while their property is being remodelled. This can certainly add to the overall cost of your extension.

Factors that Affect Costs

Having a kitchen extension built isn’t a ‘one size fits all scenario’ with a typical fixed cost. There are plenty of different issues which can affect the cost of your renovation – even if you’ve chosen the same type of extension as your neighbour opposite.

The type of professionals you require ie soil samplers, tilers, and carpet fitters, will matter as well as whether they are self-employed or work with a company (the size of that company will also matter since larger companies will tend to charge more). In addition, extensions to property in London will always cost more, due to the higher cost of labour there.

Size & Type of Extension

The size of the extension will obviously affect the price, as will the difficulty (or simplicity) of the design

A wraparound extension will be far larger and more complex to build than a single storey rear extension so will obviously cost more. The same applies to a double storey extension. An extension can be any size and the larger it is, the more materials you’ll use and the longer tradesmen will remain onsite.

Structural Changes

If you have a neighbour whose property adjoins your own then you’ll need to get a party wall agreement. This can come to as much as £1000 and you’ll require the assistance of a structural engineer.

Surveys you may be asked to undertake before starting the build, in order to comply with Building Regulations, include those for the potential of flooding and how the build will affect the natural environment and wildlife in the area. These typically cost around £700.

Quality of Kitchen Components

A newly renovated kitchen

The type of materials you choose will certainly have a bearing. A worktop with a composite finish will cost a lot less than one made from Italian marble, for instance.

When it comes to fitting out your kitchen extension, there’s a rough estimate of what the materials, such as cabinetry, worktops and appliances will cost.

The percentage is based on the overall value of the property, with five per cent spent on the interior of the new kitchen extension. This breaks down further into:

  • 30 per cent of your budget on cabinetry
  • 15 per cent on appliances
  • 10 per cent on worktops
  • 5 per cent on flooring

Planning Permission Fees

As well as complying with Building Regulations, your extension may also require planning approval (which costs around £200 per application).

It can be possible to use permitted development rights to add on a ‘larger rear extension’, but this must be given the go ahead by the local authority. An application for this is around £100.

Reasons to Get a Kitchen Extension

If you need more space for a growing family then having a kitchen extension built is far more cost effective than having to move house. It’s also less hassle. And, not only that, but you get to stay with the nice neighbours.

Another plus point of an extension is that you’ll usually recoup a lot of the cost when you do eventually come to sell the house. That’s because it will add value, meaning you can sell for a higher price.

DIY Vs Hiring a Professional

Yes, you’ll pay a lot more to have your kitchen extension professionally built, than if you do it yourself. But, you’ll also have the peace of mind that it’s been done properly, and in a reasonable timescale.

You’ll also get a legal guarantee with the extension if it’s been carried out by a team of professionals.

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