Kitchen Extension Cost

Thinking about getting a kitchen extension?

Kitchen extensions are a type of extension which remains popular in the UK. Not only can a high-quality kitchen extension boost the value of a property, but it also gives homeowners the opportunity to adjust a space to make it more functional for their needs.

But how much does a kitchen extension cost in the UK?

In 2025, the average kitchen extension cost is between £25,000 – £35,000. This includes materials and labour charges. However, the cost of a kitchen extension can vary significantly depending on the type, size, and quality of the installation.

Bear in mind that the cost of a single storey extension with a kitchen fitted may only be one element of a renovation. If you choose to build a multi-floor space, the cost of a double-storey extension can be around £60,000.

This guide covers everything you need to know, including how much different-sized kitchen extensions cost, how much the cost of a kitchen extension per m² varies depending on the quality of installation and finish, and much more!

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How Much Is a Kitchen Extension?

Your location can affect the cost of a kitchen extension as well as the complexity of the job. The size of the extension, the finishes, the flooring, and the kitchen type can also affect the overall cost.

The average cost for a kitchen extension is around £25,000 – £35,000. In London, this price could be closer to £40,000 – £55,000.

You will need to think about the original demolition costs, the build itself, and the new kitchen.

The build quality is important too, for example:

• A straightforward kitchen build will usually cost around £1,320 – £1,620 per m².
• A good quality build would be around £1,700 – £2,000 per m².
• An excellent quality build will cost around £1,800 – £2,500 per m².

There are many variations when it comes to building a kitchen extension. A small, basic kitchen extension could cost as little as £12,000. A larger extension with top-quality kitchen fittings could cost in excess of £100,000.

If you need some inspiration, check out our complete kitchen ideas guide!

Kitchen Extension Prices

Below is a table highlighting the costs for different types of kitchen extensions based on their size and finish:

How Much For Kitchen Extension Materials?

Below is a table highlighting the supply costs of a kitchen extension. This indicates all of the costs that may come up without the cost of labour:

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Additional Kitchen Extension Costs

There are a number of additional costs that may come up when it comes to fitting a kitchen extension.

Below is a list of the additional costs that you may need to think about with this type of work:

Light Fitting Cost

When you get a kitchen extension, you may need to move your light fittings so that they are centred in the room.

Although you could choose to re-install the existing lighting fixtures, now might be a good time to update them.

The average cost of installing a new light fitting is around £80 – £200. The cost will depend mostly on the type of light fitting that you are having installed.

New Radiator Cost

When your kitchen is extended, it may require a larger radiator to heat the extra space in the room, or you may just want to upgrade to a more efficient radiator that will heat the space more quickly.

The average new radiator cost is around £200 – £300. This would include materials and labour costs, but the exact cost will depend on the radiator's type and size.

If you are moving the radiator to a new location, then this will require extra plumbing work and could end up costing much more.

Window Installation Cost

Your new kitchen extension may require at least one new window, depending on the size of the extension and how much light is needed to brighten the room.

The average double glazing cost is around £200 – £600. This typical cost includes materials and installation, but the final cost will depend on the size of the window and the difficulty of the job.

What Is the Cost of Kitchen Extension Labour?

Let's take a look at labour costs and timescales for this type of job.

When it comes to building a kitchen extension, there are many different parts to the job, and you will need to hire more than one contractor to get all of the work done.

Below is an overview of the contractors that you may need to hire for this type of work:

Interior Designer Cost

If you don't have a complete idea of what you're looking for with your new kitchen extension, an interior designer could help you design your dream kitchen.

They will work with you to create an aesthetically pleasing space that is fully functional and ticks all of your boxes. An interior designer will usually charge around £25 – £60 per hour on average.

Structural Engineer Cost

It's a good idea to hire a structural engineer before you go through with an extension, as they will be able to advise how practical the extension is and will be able to establish all of the alterations you can make during the extension.

They will also advise you on the materials needed to complete the job and how to ensure the new structure is safe. A structural engineer will usually charge around £40 – £100 per hour on average.

Builder Cost

Once you've got your design in place and it's ready to go, you can then start contacting builders for a quote on the building work. This way, they'll be able to give you a much more accurate price.

Always ask the contractor for examples of their previous work so that you can ensure they can complete everything you're asking for to a high standard.

You can expect to pay around £140 – £250 per day on average to hire builders for this job.

Kitchen Installer Cost

A kitchen installer can provide you with a complete, high-quality kitchen fitting. They will provide designs and manufacture units for your dream kitchen.

They will also take care of all of the installation work.

All of this will usually come as a complete price. Alternatively, you can buy your own kitchen and hire a kitchen fitter to do the installation work.

You can expect to pay around £125 – £160 per day on average for a kitchen fitter.

Carpenter/Joiner Cost

If you are having wood cladding installed on your extension, or if you would like to have hardwood floors installed, you may need to hire a carpenter or joiner to do this part of the work.

You can expect to pay around £130 – £180 per day on average for this part of the work.

Plasterer Cost

Once the extension is built, you will need to plaster the ceilings and walls. Many plasterers can also render the exterior of your extension if you wish.

A plasterer will usually charge around £100 – £170 per day on average.

Window Fitter Cost

A window fitter will be able to fit any window you want in your new extension. They can also install additional things such as bi-folding doors, sliding doors, or even a skylight. A window fitter will usually charge around £110 – £170 per day on average.

Roofer Cost

A roofer will be able to design the roof for your extension to your requirements. This is someone who specialises in roofing construction, and so they will be able to offer the best advice.

They will also design and build a suitable roof for your extension, which is aesthetically pleasing. Roofers will usually charge around £145 – £225 per day on average.

Painter and Decorator Cost

A painter and decorator will handle the décor of the interior and will be able to offer you the best advice on how to get your kitchen looking perfect.

They will paint and wallpaper your walls and will also gloss wooden areas such as the doorframes. A painter and decorator will usually charge around £100 – £190 per day on average.

You can choose to hire a company to handle the entire extension for you. This will include all the building work, fixtures and fittings, and decorating.

Alternatively, you can take a look at the information above and shop around for various contractors for each part of the job.

Fitting a new kitchen extension will take several weeks and possibly even months to complete.

The timescales can vary greatly depending on the type of extension, the extension's size, and the additional work included, such as fitting the kitchen and any extra plumbing or electrical work needed.

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What Impacts the Cost of a Kitchen Extension?

Several factors can affect the cost of your kitchen extension. You can find a list of these cost affecting factors below:

Size of Extension

The size of the kitchen extension will affect the overall cost of the job. The larger the extension is, the longer the job will take, plus you will also need more materials for a larger job.

Quality of Extension

The quality of the extension will also affect the overall cost that you pay. You can pay more for top-quality materials.

If you choose to do this, the job's overall cost will increase depending on the difference in price for those materials.

It's a good idea to shop around for the best materials to suit your particular extension and your budget.

Electrical Work

There may be some electrical work involved with building your new extension. You may need new sockets or wiring for the lights.

Also, depending on the age of your home and the condition of your current electrical system, you may need to upgrade your electrics altogether.

An electrician will usually charge around £120 – £350 per day on average.

Plumbing Work

When your extension is complete, you'll likely need some plumbing work in your new kitchen.

This can include connecting the water supply to the pipework and drainage systems, installing new pipework, and connecting your appliances to the water system.

A plumber will usually charge around £120 – £250 per day on average.

Location in the UK

The location of your property can affect the overall cost of your kitchen extension.

Those based in London can expect to pay anywhere from 10% – 50% more for their kitchen extension than those based in the North or other parts of the UK.

What's Involved in Building a Kitchen Extension?

The specific process for building a kitchen extension will vary based on your home's requirements.

However, you and your contractor are likely to work in different phases, with each phase representing different stages of the project.

Before any work takes place, you should ensure access to the site is clear and that the area is safe for building. It's also important to get all materials for the early phases of the project before work begins.

The list below provides a rough guide to building your kitchen extension. It is a basic framework and should not be relied on absolutely - speak to your contractor and tradesmen about the specific steps you will take.

Preparation Work

Ahead of any kitchen extension work beginning, you will need to be clear about the scope of the work and whether any planning permission is required.

This is likely to include a site survey, plus checks on services like electricity and any necessary asbestos checks or Party Wall checks.

Phase 1 - Foundations

• Builders will come and dig up your foundations.
• Building control will need to attend to approve the new foundations.
• Reinforcements will be laid in the foundations if required.
• Pipework and drainage systems will be installed in the foundations.
• Foundations poured, and the base will be prepared.
• Building control will return to approve the groundwork.

Phase 2 - Building the Structural Shell

• Bricklayers will build and install a damp-proof course.
• Lintels will be installed within the brickwork if required.
• Desired base flooring will be installed.
• Floor insulation will be installed.
• Building control will attend and conduct another inspection.
• Builders will create blockwork and brickwork.
• Cavity wall insulation will be installed.
• Lintels for the windows and doors will be fitted.
• Wall ties will be installed to fix the walls together.
• Steels and pad stones will be installed.
• Joins will be finished to a good standard.
• The door and window frames will be installed.
• All internal walls will be erected.

Phase 3 - Roofing

• Your carpenter or joiner will now build the structure for the roof.
• Rooflights and dormers will be fitted if required.
• The roof battens will be cut to size and fitted over the roof membrane.
• Roof slates or tiles will be installed.
• Finishing details of the roof will be installed, primed and painted/stained.

Phase 4 - Rendering and First-Fix Services

• Any external rendering will be completed if required.
• Drainpipes and guttering will be installed.
• Pipework, drainage, and electric work will be carried out.
• The floor screed will be installed.

Phase 5 - Windows, Doors and Weatherproofing

• Doors and windows will be installed.
• The extension will be sealed off at this point.

Phase 6 - Insulation, Plastering and Second-Fix

• Walls will be boarded and insulation inserted.
• Plastering will be completed and should be left to completely dry according to the manufacturer's instructions.
• The remaining electrical work will be carried out, and the sockets will be made live.
• Appliances will be plumbed in.

Phase 7 - Kitchen Installation

• Your choice of flooring will be installed.
• All kitchen units will be installed.
• Appliances will be commissioned and checked.
• Any relevant Gas Safe certificates or other relevant documents will be provided.

Final Stages

Once the kitchen extension has been completed, it will be thoroughly checked for problems with heating, electrical systems, plumbing, or door and window issues.

Any issues found will be rectified, and then building control will need to sign off on the finished project.

Can I Build a Kitchen Extension Myself?

A complete kitchen extension is unlikely to be within the scope of a homeowner's DIY project. As a job with many different elements, one person is unlikely to have all the skills needed to complete it.

There are many building regulations that need to be followed, and the job can take an extremely long time, even with a team of experienced contractors doing the work. It's important that an extension is built safely and correctly.

All that said, you may be able to lower the cost of a kitchen extension by managing the project yourself and dealing with individual trades rather than paying someone else to be an overarching contractor.

Building Regulations & Planning Permission for Kitchen Extensions

Many kitchen extensions are classed as permitted developments, so there is no need to apply for planning permission. To ensure your kitchen extension is compliant, you generally need to make sure:

• It is no taller than four metres.
• The extension does not extend further than six metres past the rear of an attached property or up to 8 metres for a detached home.
• The build is a single-storey extension less than half the size of the current building.

Before building a kitchen extension, you should contact your local council to check whether the job will fall under permitted developments.

It is crucial to ensure you check before starting the build. If you don't, you can be forced to demolish your kitchen extension at your own cost.

You may need to obtain a party wall agreement and notify your neighbour before the build if you live in an attached property that shares walls.

Building Regulations

Building regulations approvals may be required at certain stages of the build.

To ensure your build follows regulations, you should hire a qualified contractor who has experience with kitchen extensions.

You or your contractor will need to either provide a submission to the local authority or use an approved inspector to assess the work at various stages of the build.

Types of Kitchen Extensions

There are various types of kitchen extensions that you can choose from. Below is a list of the most popular kitchen extensions:

Rear Kitchen Extension Cost

A rear extension is erected at the back of the house and often uses up space in the rear garden.

This is a great option for those who live in terraced or semi-detached houses who may not install a different type of extension due to the nature of their property. It also works great for detached houses.

Rear extension costs typically range from £30,000 to £60,000.

Side Return Kitchen Extension Cost

A side return extension uses up space at the side of the house. This is a great option for those who don't want to use up their garden area.

This type of extension is only suitable for semi-detached or detached homes with adequate space at the side for building.

The typical side extension cost is between £30,000 and £60,000.

Wrap-Around Extension Cost

A wrap-around extension is a combination of the side return extension and the rear extension.

This is a great option if you are looking for a large extension or don't want to take up too much room on either side of the house. This option will only work on semi-detached or detached properties.

The price you pay for each of these extension types will depend on the size of the extension, the quality of the build, and your location in the UK.

Wrap-around extensions cost approximately £40,000 to £70,000.

Benefits of Building a Kitchen Extension

There are several benefits to building a kitchen extension. Below is a list of the main benefits when it comes to this type of work:

Aesthetics

Having a kitchen extension allows you to create more room in the kitchen so you can install aesthetically pleasing features such as a centre island. It will also open up the room and make it appear brighter and less cluttered.

You can do many things with the extra room, including adding a seating area, adding a bar, or adding extra cupboard space.

Installing a kitchen extension will give you all of the opportunities to create an inviting space for hosting, serving family meals, and maximising the room's appeal.

A kitchen extension is a very desirable feature and will add value to your home when you come to sell it.

Practicality

A kitchen extension will provide you with a lot of extra space. You can use this space for several things, such as storage, which will allow your home to appear tidier and less cluttered.

You could also incorporate a seating area in the kitchen in the form of a kitchen diner extension, which may free up another room in the home that can then be converted into something else.

As your family grows, it may be practical to increase your kitchen's size to accommodate preparing extra or larger meals.

Checklist: Hiring Contractors to Build a Kitchen Extension

You will need to consider a few things before hiring contractors to install an extension for you.

Below is a list of some of the main things that you should consider when looking for the right contractors for the job:

• Does the contractor offer any guarantees with their work?
• How much is the work to complete? – Ask for a breakdown of costs so you can ensure you are paying a good price for each element of the job.
• Is the contractor experienced in building the type of extension that you are looking for?
• How many years' worth of experience does the contractor have in building extensions?
• How many contractors will carry out the job?
• Will the contractor fix any issues that may arise?
• Will the contractor take care of any relevant waste removal?
• Do you need to hire any additional contractors for different parts of the work?
• Will the contractor follow all of the relevant building regulation guidelines?

FAQs

Sources

https://www.planningportal.co.uk/permission/common-projects/extensions/planning-permission
https://www.nationwidehousepriceindex.co.uk/reports/dwd
https://thesethreerooms.com/projectplanner/can-i-have-a-kitchen-extension-without-planning-permission/
https://craymanor.co.uk/kitchen-extension-types-explained/
https://www.mdbespokesolutions.com/blog/electrical-safety-kitchen-extension/
https://www.davesdiytips.com/building-a-house-extension-a-step-by-step-guide
https://www.akbloftconversions.co.uk/news/benefits-kitchen-extension