Kitchen extensions: expert planning advice and design ideas | Real Homes

Kitchen extensions: expert planning advice and design ideas

This is everything you need to know about planning a kitchen extension. Get your project off the ground with our planning and costing advice, plus design ideas

Kitchen extension: IDSystems Edge sliding doors on kitchen extension
(Image credit: IDSystems)

Kitchen extensions can help make best use of your space. Even a simple or small kitchen extension can be the ideal solution to an awkward and not so functional room, plus, it will more than likely increase the value of your home too. 

So extending a kitchen is an exciting building project, and we've put an easy-to-follow kitchen extension guide together – complete with design ideas – to help you plan yours like an expert.

Use the jumplinks below to easily navigate this page, and once you're settled on how to plan a kitchen extension, be sure to take a moment and check out our kitchen ideas feature where you'll find endless inspiration and design know-how for all your future kitchen projects.

Want more detailed advice on pricing your kitchen extension project? Check out our guide to kitchen extension costs and use our free extension cost calculator to get an idea of how much your project is likely to cost.

The practical bits of building a kitchen extension are about appointing a builder or architect and getting planning permission, but before you start, you really should get a feel for how large the extension will be and you can do this by working out what you need from it.

When it comes to how to plan a kitchen extension, you’ll be able to come up with your ideal design by considering your existing surroundings and what you have to work with. Determining how you will want to use and enjoy your extension once complete will help you decide on what the room's layout should be. 

You may have some dead garden space to work with, an old conservatory or room in the side return, and these are all great starting points for your kitchen extension design. Think about how you will use your new space throughout the seasons, how to make garden access easy, and the best ways to bring in more natural light too. Whether you’re thinking about an L-shaped, small or side-return extension – we have plenty of kitchen extension ideas below to help inspire you.

From there, it's all about the budget and we have plenty of advice on managing costs for when it comes to building a kitchen extension below too. 

So keep scrolling to take a look at our kitchen extension advice, to make sure that yours is designed and planned properly from the start. Be sure to use our ultimate guide to extending a house for further practical planning advice and costing information.

Planning a kitchen extension

A kitchen with a glazed sloping roof and sliding doors leading to the garden

Modern kitchen extension ideas

(Image credit: Fiona Walker-Arnott)

The amount of space you need for your kitchen extension will depend on how you plan to use it, so start here. There's no point in spending money on an extension that is too small. Too big isn't always a bonus either – a room that's out of proportion to the rest of your home or mostly empty (and therefore soul-less) isn't an asset either.

Generally, the kitchen is the heart of family life and the room we spend most time in — cooking, eating, socialising, working and relaxing — and an open-plan (or semi-open-plan) space is often the best way to use the new extension. 

The key to creating the perfect open-plan kitchen is getting the space and the layout right first, before deciding on kitchen units, design details and decoration later. Find out more about how to design an open-plan kitchen to get the interior layout right.

Read more below about designing a kitchen within an extension, but before you do, write a list of all the features that you already have in your kitchen, then add the features and appliances that you wish to add to the space.

Kitchen extension essentials:

Decide where to place the kitchen extension

Sarah Brooks kitchen has been improved by adding a glass box style extension to the side of her London home

Kitchen extensions should be completely accessible: this clever kitchen extension design allows for easy garden access 

(Image credit: Malcolm Menzies)

If you’re looking to create an additional space for a large, open plan family kitchen, the first step is to assess which area of your home will benefit the most from an extension. 

There are lots of options with kitchen extensions. You could extend at the rear or side of your home to gain extra space; in a terraced house, a side return extension might be all you need to be able to create the kitchen of your dreams. In a townhouse, it may make sense to do a basement conversion, with a light well leading up to the garden.

Small extensions to a house may not need planning permission if they fall within the definition of permitted development. Larger extensions, or additions to a flat, always need planning permission. Alterations to a listed building always require listed building consent, whether or not the work is permitted development.

Extending to the rear of your property? No extension should overly compromise the garden, so try to find a balance between creating a workable space indoors and retaining as much outdoor space as possible. 

A good architect will help and advise with this, but if you're unsure, try to visit as many homes with extensions as possible to see what works, and what doesn't. Check out our feature on creating an indoor outdoor living space, too.

Take an overview of surfaces and finishes

surface ideas when extending a kitchen

Cabinetry and island in Unique Silver Touch hot-rolled steel, from £40,000, Eggersmann 

(Image credit: Eggersmann)

If you’re intending something spectacular instead of a standard finish on surfaces make the decision early on in your kitchen extension plans as design mistakes are costly and a retrofit is a real headache. Extending the indoor/outdoor vibe can be achieved using the same bricks and tiles for internal and external walls, and some porcelain floor tiles can be laid from the kitchen straight out to the patio. Consider an alternative to a plastered ceiling. Design-wise, slatted wood appears to elongate the space and the timber brings warmth to cabinetry in cooler shades.

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Find a good architect for your kitchen extension

Once you’ve decided where you’d like your extension to be located, consult a RIBA-registered architect to find out what can be achieved.

You will need plans and construction drawings for the builder, and to show compliance with building regulations

Work with an architect or architectural technologist to provide these. ‘They can also inspire you with design solutions that you may not have considered,’ says Hugo Tugman, founder of Architect Your Home. 'Hire someone who specialises in homeowner projects and get them to do a small amount of paid-for work, such as a sketch design, to see if they are the right person for the job.’

Decide how much involvement you want them to have. ‘Some only offer a full service, also overseeing construction,’ says Alan Cronshaw of Acronym Architecture & Design. ‘Others offer a partial service, ending ties after planning and building control approval are gained.’ 

Find an architect at architects-register.org.uk or an architectural technologist at ciat.org.uk.

Kitchen in the open-plan kitchen-diner with white units and wall hung cabinets, an island with wrap-around wooden worktop, white bar stools and black mesh pendant lights

(Image credit: Katie Lee)

Put the kitchen extension out to tender

Kitchen extension with a glass roof and breakfast bar

(Image credit: Chris Snook )

With the plans in place, you can go ahead and find reliable building contractors to tender for your extension work. Consider personal and professional recommendations, as well as through trade bodies such as the FMB (Federation of Master Builders).

Arrange to meet at least three contractors and, to obtain estimates, send them the plans, construction drawings and specification documents, plus the contract you want to use, so they can quote as accurately as possible.

 

Do you need planning permission for a kitchen extension?

If the work is classed as permitted development, you won’t need to apply for planning permission, but you may wish to apply for a certificate of lawful development, which proves the project is legal. If you do need planning permission, you will have to apply to the local council, and may need additional reports. Whichever route you are taking, you will need building regulations approval. It may be necessary to issue a party wall notice if you are building on or close to the boundary with a neighbour.

How long will a kitchen extension take?

It depends on the scale of the project, difficulties accessing the site, how bespoke the kitchen extension is and how well run your schedule is. You can expect a small kitchen extension to take between 10 to 12 weeks, while a large kitchen extension could take up to 6 months. Some will be quicker, others slower. Remember that these timings do not include the planning and design phases of your project.

Designing a kitchen extension

Designing a kitchen extension is all about the detail, and for this you might need help: from an architect, a builder and, without doubt, a kitchen designer. But don't just think about looks – design your kitchen extension equally for functionality. There are lots of places where you can find inspiration and kitchen extension ideas from, we've included plenty below, and here's how to tackle kitchen extension design for the best results.

A kitchen extension with exposed beams, light blue units and plants that hang from the ceiling

(Image credit: Chris Snook)

Prepare a detailed kitchen extension design brief

Let your designer know what you want. ‘A common mistake is to brief your architect with a set of constraints without talking through the possibilities,’ explains architect Hugo Tugman. ‘When I work with a homeowner, I discuss the brief and sketch designs around their kitchen table, to involve them and ensure that what I am creating fits their needs and lifestyle.’

Harvey Jones Linear kitchen in a kitchen extension

Photo: Darren Chung

(Image credit: Harvey Jones)

A good architect will come up with creative ideas and solutions you might not have thought of. For example, the usual bi-fold doors could be replaced with a single door, and drama created with a huge window that soars up into the apex of the roof, and a slot window with views onto the garden.

Linear kitchen (above), from £20,000, Harvey Jones.

How will you access your kitchen extension?

As one of the principal spaces in your home, the kitchen should ideally be accessible from the main hallway and not through another room,’ says property expert Michael Holmes. ‘Typically, extensions are added to the side or rear of a property to maximise links with the garden as well as create extra space internally.'

Ideally, this transition should be as seamless as possible, something which can be achieved by good layout planning, and matching interior detailing and materials, including flooring and skirting boards, for example. 

You may be able to achieve the best space possible by remodelling the existing interior layout, perhaps removing internal walls to link two rooms together, or by converting and linking an integral garage.

How will you access the garden from the kitchen extension?

The transition from inside your new kitchen extension needs to be as seamless as the transition from the original part of the house to the new room. This means putting exterior doors to the garden in a place that looks natural and is practical, both from inside and out.

Bi-fold or sliding doors that lead straight on to a patio or deck will help you make the most of the indoor-outdoor relationship within the space, creating a more successful finish. 

Think about the visual transition between the two spaces, too. Whether you have swathes of fixed glazing or install folding sliding doors, ensure you situate them to make the most of the views of the garden. 

Use our guide to choosing bi-fold and sliding doors to find out more and browse these folding and sliding door design ideas for inspiration.

Consider the kitchen extension's glazing elements

With its location, and access from inside and out sorted, consider how much glazing you want to include. This will help you make the most of light, but should be done in conjunction with planning your different zones for cooking, dining and living, plus any utility space, since the more glazing you have, the less wall space will be available. 

Consider the extension's orientation, too. If it's south-facing, you might want to consider limiting the glazing.

modern bright kitchen extension

(Image credit: Jody Stewart)

Consider a conservatory kitchen extension

kitchen and dining area in a glazed extension

(Image credit: Marston and Langinger)

This is a popular way to bring lots of light into a kitchen extension. What to bear in mind, other than ensuring you comply with planning laws and building regulations? Ensure the glazing is up to the job – both in winter and summer – of keeping the kitchen at the right temperature; if you're going to have remote controlled blinds fitted, bear in mind that they will gather dirt and grease from cooking over time so need to be easily cleaned; leave enough solid wall for fittings and fixtures to hang off; make sure any entrances and exits to the room aren't going to interfere with the cooking zones; and give the best views over the garden from any dining or living space.

Think about the kitchen extension's exterior

Consider, too, how your planned extension will look from outside. Just as you might match the detailing and materials inside to those of the original house to create a seamless transition from the existing space to the new, choosing materials that match those of your home's exterior will make the new extension blend successfully. Or, perhaps you might like to site your new kitchen in a traditional-style orangery, or go for contrast, such as with a glass box extension, for a contemporary finish?

rear extension to victorian terraced house photographed by polly eltes

(Image credit: Polly Eltes)

Where to put the kitchen within the extension

Utility room separated from main kitchen by Masterclass Kitchens

(Image credit: Masterclass Kitchens)

Ideally, the kitchen/cooking area will be in the darkest part of the new room. This might seem counter-intuitive, but ideally you want the living and dining areas nearest the garden, at the far end of the room. Those are the important zones for taking advantage of natural daylight – plus it makes more practical sense for the cooking/prep zones to be well away from kitchen doors (particularly if kids will be whizzing in and out of them.

Putting the kitchen at the end of the room that's nearest to the original part of the house gives you some scope for incorporating a utility room behind it. Divide the old room up to create a narrow utility hidden behind the kitchen, the save the space in the new extension for living and dining. The bonus? Not only have you gained a utility space that's value-adding in every sense, you've taken some of the noisier appliances out of the open-plan space.

See our utility room ideas for more inspo.

Plan the kitchen layout

Once you have the space that you want designed, you can start thinking about the kitchen layout – our ultimate guide to designing a kitchen is a helpful starting point. It is worth consulting two or three experienced kitchen designers for their ideas. Make sure you give them a clear brief of what you are trying to achieve, but listen to their advice in terms of layout to suit the space, such as designing a galley, L-shaped or U-shaped layout. Or introducing a kitchen island or appliance wall.

Generally, though, as we've said above, it's best to site the kitchen towards the back end of the extension, nearest the original part of the house, with living and dining spaces nearer the brighter, garden end of the space.

Other things to consider include:

  • Will you have floor to ceiling cabinetry to hide away a small utility space or will you factor in a separate utility room?
  • Will building cabinetry within an adjoining hallway to match that of the run of units into the kitchen allow for useful under stairs storage or a concealed under stairs cloakroom?
  • Will you choose integrated, hidden appliances for a streamlined look or will they be on show?
  • Will you use the extension as an opportunity to incorporate features such as rooflights or a vaulted ceiling, or both?

a bright and light-filled kitchen extension with kitchen island

(Image credit: Philip Lauterbach - www.plpix.com)

As for practicalities, a good designer will understand the importance of function (ergonomics) and incorporate all the appliances you have specified. Once the basic layout is agreed, you can finalise details like the style of the kitchen cabinets (see our gallery for ideas) and drawer fronts, worktops and splashbacks. You can also get down to final details, such as the sink and taps.

Don't miss our feature on interior design know-how for kitchens to get these last details just right.

When you have finalised your layout and chosen your supplier, the designer will be able to produce detailed wiring and plumbing plans so the builders can put the services in place during the building phase. You can then have the plastering and decorating work done and the flooring laid, ready for the kitchen installers to arrive.

Budgeting for a kitchen extension

large white kitchen extension with contemporary finish by mulroy architects

(Image credit: Joakim Boren (Mulroy Architects))

With plans in place, you can work out how much you can afford to spend on each element of your kitchen extension, and make alterations to plans if your budget won’t allow for certain design elements. Prices will vary depending on the work you carry out, but as a guide:

  • Building work: plan for between £1,200 – £3,000 per m² and upwards;
  • New kitchen: expect to spend between £17 – £200 per m²;
  • Painting and tiling the walls will cost between £50 – £100 per m² if you use a contractor;
  • Flooring will cost between £25 – £100 per m².
  • Building regulation costs depend on what work is involved and the over all area of the proposed project, but expect to pay upwards of £200.

Green light shaker kitchen with Crittal-style windows

(Image credit: deVOL)

Are small kitchen extensions worth the investment?

Planned carefully, a small kitchen extension can have a major impact, allowing you to rejig the layout of your existing space just a little to create a whole new room, with space for dining and living where once there might not have been. 

Our guide to side return extensions is a good place to explore how you might expand and extend sideways, like in the kitchen below; a small single storey extension (check our comprehensive guide on that, too) to the rear of the house can give you flexibility, too. The key is to get the kitchen's layout just right.

Planning a kitchen extension: An open plan kitchen diner

(Image credit: Build Team)

12 kitchen extension ideas and photos

Even on a small budget, you can up your home's value and transform the look of your space, allowing for open plan living and beautiful design, all with a kitchen extension.

Whether you're looking for small kitchen extension ideas, to create a modern kitchen diner or to  kit out a 1970s semi or a Victorian terrace, be inspired by our selection of beautiful spaces below, which all happen to have cost less than £100,000.

1. A bright and spacious kitchen for £84,000

bright and spacious kitchen extension


Emma and Julien Barber spent more than a year looking for a new home after living in a 1920s semi in Swindon for 10 years. They’d viewed several houses that weren’t right for them before realising that they could create the space they needed and the house they wanted where they already were.

Their new kitchen is minimalistic, clean and uncluttered, with bi-fold doors that open out onto their lovely garden. 

The whole renovation cost £84,000, with the bulk being spent on the kitchen extension – this worked out much cheaper than the cost of moving.

2. A modern kitchen extension for £60,000

contemporary kitchen extension for entertaining


Originally, this kitchen was impractically small for the four-bedroom detached house that it serviced and the growing Lewis-Pierpoint family. They made good use of the third of an acre that their house is set in, taking out a chunk of the vast garden in order to extend their tiny kitchen.

High-gloss blue units and contemporary, white surfaces bounce light around the room from the bi-fold doors opposite the kitchen island, making it the perfect place for family dinners. In total, £60,000 was spent on creating the perfect family kitchen.

Want a cheaper extension still? Find out how to build an extension for under £50,000.

3. A £66,000 kitchen extension filled with antiques

eclectic kitchen extension with antique pieces


When Angela Hart and Richard Rush first laid eyes on this regency cottage, they knew the small galley kitchen wasn’t going to be big enough for them. As part of a two-storey extension project, the couple knocked through the downstairs bathroom and extended into the garden.

They didn’t want to spend a fortune on a kitchen that would, inevitably, be tired and out of date in 15 years, so they opted for antique furniture that was cost effective and would last a lifetime. For about £66,000 they created a quirky kitchen that would stand the test of time.

Find out more about planning a double storey extension in our guide.

4. Extending a galley kitchen for £78,000

galley kitchen extension


Like many 1940s homes, this one had a tiny kitchen that was far too small for a property of its size. The solution was to extend and open out the back of the house with vast bi-fold doors. Minimalist white units, along with white walls and ceiling, make the room feel even bigger than it already is. A use of dark wooden flooring and a charcoal feature wall creates contrast and enhances the space. Despite its size, this single storey extension was achieved for just £78,000.

Find out more about planning a single storey extension in our guide.

5. £98,000 for an industrial kitchen in London

Industrial style kitchen extension in london


This five-bedroom Victorian terraced house in south London had masses of potential for a kitchen extension. There was a lot of dead space in the side return, and an old conservatory at the rear of the house that could be put to better use. An L-shaped extension was proposed to the local planning department, and a month later, the owners were ready to go.

A row of rooflights flood the room with natural light, and big French doors at the rear open the new space out onto the garden. As the house had no remaining original features, the industrial styling fits right into the blank canvas. A spend of £98,000 transformed the original, ugly kitchen into a beautiful, industrial space.

Check out these inspiring industrial style kitchen design ideas.

6. An £85,000 side return extension

industrial style kitchen extension


Owner Pippa Mundy’s approach to renovating her Cardiff home included stripping it back to uncover interesting features, along with being flexible about her plans when she hit a speed bump. It has resulted in a truly interesting kitchen, with a reclaimed wood island at its heart.

Extending into the side return allowed for the inclusion of glazing across the roof, helped greatly by the triple-pane glass doors at the rear of the kitchen. The quirky extension was created for £85,000.

Find tips for building a side return extension in our practical guide.

7. Maximising light for £78,880

maximising light in a kitchen extension


Getting a home with the kitchen of your dreams doesn’t necessarily mean trawling the estate agents. For Frazer and Frieda Furlong, it meant patiently saving up for a decade so that they could craft the light-filled extension they'd alway dreamt of. 

Including the creative use of colour and pattern contrasts against contemporary units and warm woods in their kitchen extension plans, while the whole room was brightened by rooflights and solid wooden sliding doors too, resulted in a dynamic and inviting finish. The exterior contrasts with the rest of the building, as it is rendered in a modern blue, with silver decking leading down to the garden. Spending £78,880 has given the Furlong family exactly what they wanted.

Find more information and ideas for creating a light-filled extension in our guide.

8. A £72,000 kitchen diner extension

Modern family kitchen extension


Ian and Gillian Roberts bought this home with the intention of carrying out a complete renovation in 2008. Then the family was shipped off to Hong Kong for Ian’s job before the project could get underway. On returning, the family were faced with either a massive renovation project, or another move.

Instead of taking the easy option, they jumped into the renovation. Their kitchen, now situated in an extension that used to be dead garden space, is a modern, bright kitchen diner extension. It is filled with light by a glazed wall at the end, and large rooflights above. The kitchen extension cost about £72,000.

Find out more on house renovation in our comprehensive guide.

9. A family kitchen extension costing £58,000

new family kitchen extension in a 1960s house


When Paul Reid took his partner, Elaine, to view this 1960s detached house, the galley kitchen was a far cry from what she had pictured. The units were falling apart, it was brown and mustard and was only serviced by electricity. It was a nightmare from the 1970s, unaltered and out of date.

The couple went for a streamlined look with their final design, opting for contemporary, eye-level ovens and curved units. They may have spent a little extra on essentials like worktops and units, but saved overall by adapting their design and cutting out appliances that they didn’t need. From an unattractive galley kitchen they have created this luxurious space for just £58,000.

For more family-inspired ideas and other kitchen design advice check out our dedicated page.

10. A small kitchen extension costing £74,424

scandinavian style kitchen extension

After an ambitious two-storey extension to Nicola Wilkes and Stuart Davies’ 1960s home left them squeezed for funds, the couple had to get creative when it came to designing a new kitchen at the end of their renovation project. 

Rather than going all out, the couple put some clever small kitchen extension ideas into play and spent the money where it mattered, and made the most of their space space. The basics were kept plain and simple with reasonable kitchen units and worktops. The money went on the finishing touches to add a sense of luxury with the light fittings, tiles and furniture making the biggest impact on the space. The whole project cost £74,424 and the result was a simple but impactful Scandinavian style kitchen extension.

11. A London kitchen extension costing £68,000

Scandinavian style london kitchen extension


Having viewed a lot of beautiful houses in the Finsbury Park area, Emily and Angus Grierson decided this was the place for them. The problem was, they didn’t want to move into a perfect house that had been pre-renovated by someone else. They wanted to do it themselves.

When this house, ripe for extension, came up for sale, they snapped it up and picked up their tools, ready to turn it into their home. The building grew out into the garden and the extension housed the new, open plan kitchen – a bright and colourful space, perfect for the couple’s needs. The project cost them £68,000.

12. £95,000 side-return kitchen extension

side return kitchen extension


Mel and Alex Walker purchased this three-bedroom house in south-east London, recognising that it had a lot of potential. The side-return wasn’t utilised and presented the perfect opportunity for an extension. Fortunately, an architect worked out of the same office block as Alex, so they enlisted him to help with their project.

The plan included a dining area next to the kitchen and a pitched roof; that way they could incorporate Velux windows, which, together with the bi-fold doors, would bring in copious amounts of light. To create their perfect extension, the couple spent £95,720. Not an unreasonable sum for such and incredible house.

Read more about kitchen extensions: