How Much Does a Kitchen Extension Cost in London?
With decades of experience designing stunning kitchen extensions across London, I’ve written this guide to help you understand the true cost of a kitchen extension in London in 2024.
East London kitchen extension by ONDINE London. Source: The Japandi House
How much does a kitchen extension really cost in London?
One of the most common questions we receive before working on rear and infill kitchen extensions in London is, ‘How much will it really cost?’
It’s a tricky one to answer because no two projects are the same. But after working on many bespoke kitchen extensions in London we've come to understand the nuances involved in pricing these projects.
Below, I’ll walk you through the key factors that influence the cost of a kitchen extension in London and share real costs from projects we’ve completed.
North London rear kitchen extension we completed in 2021. Source: The Finned House.
Average cost of kitchen extensions in London based on real projects
Here’s a breakdown of average costs for different types of extensions, drawn from real projects we’ve worked on across the city.
Side- infill only kitchen extension average cost: £70,000 - £90,000
A side return extension typically involves extending into the unused alley space along the side of your home. This has long been a popular choice for our clients with Victorian and Edwardian terraced houses in London, as it allows for a more open and spacious kitchen without losing garden space.
What’s Included: A basic side return extension in London will usually cover structural work, extending the footprint of the kitchen, and installing standard finishes like off-the-shelf cabinetry and fixtures.
Real Example: Project in Hackney – Cost: £120,000.
We worked on a side return extension in a Victorian terrace in Hackney. The project involved creating an open-plan kitchen with mid-range materials, but costs were slightly elevated due to the need to match the original brickwork and reinforce neighbouring walls.
What Affects the Cost: Structural work can drive up costs, particularly when adding steel beams or matching period architecture.
Side & rear kitchen extension average cost: £85,000 - £140,000
A rear extension is one of the most popular choices among our clients at Ondine London. It’s a fantastic option for creating a larger kitchen-diner space that opens up to the garden, blending indoor and outdoor living.
What’s Included: A rear extension in this price range typically includes mid-range materials, such as stone countertops, semi-custom cabinetry, and possibly underfloor heating. It can also involve significant structural work, especially when removing walls.
Real Example: Project in Islington – Cost: £150,000.
This rear extension opened up the back of a period property in Islington, creating a modern kitchen-diner. The project costs increased due to custom bifold doors and underfloor heating throughout the space, but the result was a light-filled, functional kitchen that blended with the character of the home.What Affects the Cost: Structural complexities like removing load-bearing walls, installing steel beams, and adding large glazing elements (like bifold doors or skylights) can significantly impact costs. Additionally, higher-end finishes such as bespoke cabinetry or premium flooring will push the budget upwards.
Wrap-around kitchen extension average cost: £200,000
Wrap-around extensions combine a side return with a rear extension to create an L-shaped space that maximises your kitchen area. These projects always tend to be larger and more complex, often involving fully bespoke designs, premium materials, and custom-built features.
What’s Included: A wrap-around extension in London often includes full custom cabinetry, luxury finishes like marble countertops, integrated appliances, and design elements like roof lights or statement glazing.
Real Example: Project in Hampstead – Cost: £245,000.
In Hampstead, we completed a large wrap-around extension for a period property. This project featured a fully bespoke kitchen with hand-crafted joinery, premium appliances, and large skylights that filled the room with natural light. The complexity of the design and the high-spec materials contributed to the final cost.What Affects the Cost: The design complexity and choice of materials are key cost drivers. Bespoke cabinetry, high-end fixtures, integrated technology, and moving services like water or gas can add to both the timeline and the budget.
7 key factors that influence the cost of a kitchen extension in London
In our experience, seven key factors will impact the cost of a kitchen extension in London in 2024.
1. Location
Your neighbourhood in London could be the biggest factor in shaping the cost of your kitchen extension.
Every neighbourhood in London has its quirks, and the location of your property will influence important costing factors like planning approvals and contractor fees.
For instance, boroughs like Kensington, Chelsea, Islington, or Hampstead often to come with higher costs for kitchen extensions - not due to the postcode itself but because of stricter planning regulations, especially near conservation areas. We also find that planning applications for extensions in these areas require more detailed drawings and considerations (which we take care of in-house).
In contrast, areas like Hackney or Walthamstow may offer more flexibility but can still involve similar challenges if they fall within conservation zones. Navigating London planning regulations can be challenging, but understanding them is crucial for accurately budgeting your kitchen extensions.
2. Size and type of kitchen extension
The size and type of extension you choose will have a significant impact on cost.
There are several types of kitchen extensions available, but for London’s Victorian period properties, the most common is a side infill and rear extension. This allows for a spacious, light-filled kitchen at the back of the property, creating a seamless transition to the garden and transforming the home into a calm, inviting sanctuary.
A wrap-around extension is an option, though it suits standalone houses better, while terraced homes often benefit from a rear side infill extension. In London, where terraced houses dominate, we frequently receive requests for this type of extension, which often includes pitched glass roofs and large sliding doors, offering a strong connection to nature and the garden beyond.
The scale of your kitchen extension is generally limited to no more than 50% of the available garden space
At Ondine London, we work extensively on period properties, primarily Georgian and Victorian terraces. Our focus is on bringing these homes up to modern standards, especially by maximising light. Whether it’s through rear or kitchen extensions, loft conversions, or clever use of glass elements like sliding doors, roof terraces, or pitched roofs, we design spaces to bring in as much daylight as possible - turning homes into light-filled sanctuaries.
3. Planning permission & regulations
If you own your entire home (not divided into flats), we can generally apply for planning permission through permitted development or the neighbourhood consultation scheme. These options tend to secure approval more quickly.
For homes in conservation areas with stricter regulations (such as an Article 4 direction), full planning permission is required. We work closely with planning officers to ensure timely approvals.
A typical cost of generating a planning application can vary from around £2k to £4K depending on the scale of your project
The scale of your kitchen extension is generally limited to no more than 50% of the available garden space. This rule of thumb provides a good idea of the extension size you can achieve. Whether your home is terraced, end-of-terrace, or standalone will influence which type of extension-rear, side-infill, wraparound, or loft conversion—you can apply for. Once this is determined, the scope of the project is set against a thorough budget calculation prepared by our quantity surveyor (QS) to ensure a clear financial plan.
4. Materials & finishes
The materials and finishes you choose will greatly influence the cost of your kitchen extension. Elements like countertop materials can greatly impact your overall budget.
For example, marble countertops, especially leathered marble, add a luxurious touch but come at a higher cost. Corian, which we often work with, is a more affordable option available in a wide range of colours and finishes. Quartz is another popular choice - particularly marble-effect quartz, which provides the look of marble but with greater durability and cost-effectiveness.
Another major budget consideration is kitchen flooring. Modern poured concrete with underfloor heating offers a sleek, modern aesthetic, while options like beautiful parquet or mansion weave timber flooring provide a classic finish. For a more budget-conscious option, bespoke encaustic tiling delivers a unique aesthetic at a lower cost.
Hardware, fixtures, and fittings (FF&E) also influence your budget. We create extensive FF&E lists for our clients showing all the suppliers from our trusted little black book of interior shops and suppliers. We can offer trade discounts on these options again working closely with you, our clients on achieving a beautiful end result within budget.
5. Structural work
Structural work, such as removing load-bearing walls, is often a key part of kitchen extensions.
People often feel intimidated by the idea of removing load-bearing walls, assuming it’s costly. In fact, this is a common part of Victorian rear kitchen extensions, especially when moving the rear wall to accommodate a rear or side-infill extension.
Our in-house structural engineer calculates the steel - or the RSJ (Reinforced Steel Joist) - needed, and our contractor sources it through trade accounts, ensuring this process is straightforward. We carry out these calculations and steel installation on a daily basis and can reassure you it is not a complex issue and will not greatly affect your overall budget.
Sometimes basement excavations are part of kitchen extension work, creating space for a kitchen, utility room, or even a home gym. In these cases, underpinning may be necessary to ensure structural integrity, but we assess everything with soil tests and transparent budgeting before work begins.
6. Labour & contractor costs in London
Labour costs in London are typically higher due to the greater demand and the complexities of working in busy city environments.
Tasks like navigating machinery and securing local council permissions for material deliveries—such as steel or soil removal—can add to the cost of your kitchen extension.
Material delivery often requires securing council permissions to keep parking spaces free for efficient delivery of bigger ticket items like steel or soil removal from basement excavations.
At Ondine London, we handle these tasks daily. We act as the lead contractor on all our projects, ensuring smooth communication between our design team at the studio and project lead Philip MacMahon, who works closely with the site manager assigned to your job. This structure allows us to tackle queries quickly and efficiently on-site, resulting in faster project turnarounds and reduced costs.
7. Design complexity
The complexity of your kitchen design plays a key role in cost.
As bespoke kitchen designers, we offer a variety of materials to suit different budgets. For instance, we can manipulate timber veneers so that the visual effect looks like solid timber, giving a rich materiality to the project but allowing the budget to not sky-rocket. We can then decide on the internal carcass material for inside the cupboards. Again this can vary from solid timber to a timber veneer to a melamine finish.
Hardware choices, from brushed brass to powder-coated black steel, also influence your budget. So will kitchen appliances. We collaborate closely with you to ensure design decisions align with both your vision and financial plan, while still achieving a stunning result.
A kitchen extension we completed in a terraced Georgian house. Source: Glass House
What else can affect the final cost of a kitchen extension in London?
Hidden costs: It’s always a good idea to budget for the unexpected. Hidden structural issues, like needing to replace old pipes or dealing with poor foundations, can quickly increase costs. We recommend setting aside around 10-15% of your budget for contingencies.
Labour and contractor costs: Labour rates in London tend to be higher than in other parts of the UK due to demand. Experienced contractors are worth the investment, especially when working on period properties where specialist knowledge can prevent costly mistakes.
Material lead times: Waiting on premium materials or custom-made items can delay a project and add to the budget. If you’re set on bespoke features, it’s important to factor in both the cost and the lead time for materials.
We’ll help you cost up your kitchen extension
The most accurate way to estimate the cost of your kitchen extension is to review your specific design ideas and requirements. We’re happy to discuss your plans directly and provide a tailored breakdown to ensure your project fits within your budget.
