Quick answer: how much does a kitchen extension cost in Kent?
A fully fitted single storey kitchen extension in Kent typically costs £55,000 to £110,000 in 2026, depending on size and finish. The building shell alone runs at roughly £2,750 to £4,500 per m² once you apply the South East uplift. A small 12 to 15 m² rear extension sits at the lower end. A large open-plan kitchen-diner with bi-fold doors and a premium kitchen sits at the top.
A kitchen extension is a ground floor extension that adds space for a new or enlarged kitchen, usually a kitchen-diner at the back or side of the house. Price is driven by four things: floor area, ground conditions, how much steel and glazing you want, and the kitchen you put inside it.
This guide gives you Kent prices by size, where the money goes, the costs people forget, and the planning rules that decide whether you need a planning application at all.
How much does a kitchen extension cost per m² in 2026?
Published UK guides put a standard single storey shell at £2,200 to £3,200 per m² in 2026, rising to £3,200 to £4,500 per m² for London and complex structural schemes, according to BestBuilders (updated July 2026). The same guide adds 25 to 40 per cent for London and the South East. Tradesperson quotes collected by MyJobQuote (6 October 2026) are lower, at £1,700 to £2,500 per m² for a finished extension.
Why the gap? The lower figures often exclude the kitchen, professional fees and groundworks surprises. Treat every national number as a guide and use the Kent table below to plan. Only a site visit and a fixed, itemised quote give you a real price.
| Source (2026) | What it covers | Cost |
|---|---|---|
| BestBuilders, shell only | Standard single storey rear extension | £2,200 to £3,200 per m² |
| BestBuilders, shell only | London and complex structural schemes | £3,200 to £4,500 per m² |
| MyJobQuote, mid-range finish | Turnkey extension including kitchen | £1,700 to £2,000 per m² |
| MyJobQuote, London and South East | Typical total for a kitchen extension | £55,000 to £90,000 |
Sources: BestBuilders kitchen extension cost guide (July 2026); MyJobQuote kitchen extension cost (6 October 2026).
What does a kitchen extension cost in Kent by size?
For a typical Kent home, a small rear extension of 12 to 15 m² costs about £52,000 to £81,000 fully fitted, a standard kitchen-diner of 18 to 22 m² costs £69,000 to £112,000, and a large open-plan space of 25 to 30 m² costs £94,000 to £154,000. These are our calculations: BestBuilders’ national totals with its 25 to 40 per cent South East uplift applied.
| Extension type | Size | UK fully fitted (BestBuilders) | Kent estimate (+25 to 40%) |
|---|---|---|---|
| Small rear | 12 to 15 m² | £42,000 to £58,000 | £52,000 to £81,000 |
| Standard kitchen-diner | 18 to 22 m² | £55,000 to £80,000 | £69,000 to £112,000 |
| Large open-plan | 25 to 30 m² | £75,000 to £110,000 | £94,000 to £154,000 |
| Side-return | 10 to 16 m² | £50,000 to £82,000 | £62,000 to £115,000 |
| Wraparound | 28 to 40 m² | £88,000 to £135,000 | £110,000 to £189,000 |
Kent estimates are our arithmetic from published ranges, not quotes. They include the kitchen, finishes and fees. The wide spread reflects how much the specification matters.
Where does the money go in a kitchen extension?
The building shell (groundworks, structure, roof and glazing) takes roughly half the budget, and the kitchen itself takes 18 to 30 per cent. The rest is electrics, plumbing, plastering, fees and Building Control. According to BestBuilders in 2026, the split looks like this:
| Cost area | Share of total | On a £80,000 project |
|---|---|---|
| Groundworks and foundations | 12 to 18% | £9,600 to £14,400 |
| Structure, roof and weathertight shell | 28 to 35% | £22,400 to £28,000 |
| Glazing | 8 to 15% | £6,400 to £12,000 |
| Kitchen units, worktops and appliances | 18 to 30% | £14,400 to £24,000 |
| Electrics, plumbing, heating, ventilation | 8 to 12% | £6,400 to £9,600 |
| Plastering, flooring and decoration | 6 to 10% | £4,800 to £8,000 |
| Professional fees and Building Control | 5 to 10% | £4,000 to £8,000 |
| Party wall and structural engineering | 1 to 4% | £800 to £3,200 |
Percentages from BestBuilders (2026). The £80,000 column is our arithmetic and the ranges overlap, so they do not add up to exactly £80,000.
What costs do homeowners forget when budgeting?
The most common mistake is budgeting for the shell and the kitchen but not the 20 to 30 per cent that sits around them. BestBuilders estimates that electrics, finishes, fees and party wall costs together create a £10,000 to £20,000 shortfall for people who miss them.
- Opening up the old kitchen wall: removing an internal wall costs £1,200 to £5,000 depending on whether it is load-bearing, and a steel beam adds to that (Federation of Master Builders, updated February 2026).
- Deeper foundations: clay and tree roots are common across parts of Kent. A foundation depth overrun can add £3,000 to £12,000.
- Drains: a manhole in the wrong place can mean diverting the drain or building over it, which needs Building Control approval.
- Temporary kitchen, skip and scaffolding: small items that add up over a 12 to 16 week build.
- Contingency: hold 10 to 15 per cent aside.
What structural work does a kitchen extension need?
Most kitchen extensions need a steel beam where the old rear wall comes out, plus temporary propping while the opening is formed. A structural engineer sizes the steel, Building Control inspects it, and the order of propping, cutting and lifting decides whether the house stays safe and the programme stays on track.
This is the part of the job where an experienced main contractor earns its fee. Opening a whole rear wall for bi-fold doors puts the load of the floors above onto a new beam, and the padstones and foundations under each end must be right. BDC handles steelwork, propping and wall removals in-house, working with structural engineers and architects on each job. See our house extension and new build services in Kent.
Do you need planning permission for a kitchen extension in Kent?
Often you do not. Many single storey rear extensions are permitted development, which means no planning application is needed if they stay within set limits. You still need Building Regulations approval for every kitchen extension, whether or not planning is required.
Permitted development is a national right to extend without a full planning application. The standard limits for a single storey rear extension are:
- Up to 3 m deep on a semi-detached or terraced house, and up to 4 m on a detached house.
- Up to 6 m (semi-detached or terraced) or 8 m (detached) under the larger home extension prior approval scheme, where neighbours are consulted.
- Maximum height of 4 m, and 3 m if within 2 m of a boundary.
- Materials must broadly match the existing house.
These rights are removed or restricted for flats, listed buildings, and many homes in conservation areas or where the council has made an Article 4 direction. Several Kent villages and the older parts of Maidstone, Tunbridge Wells and Sevenoaks fall into these categories, so check with your local planning authority first. Our guides to planning permission for an extension in Kent and permitted development in Kent explain the process in detail. If a Party Wall notice is needed, a surveyor typically charges from about £90 per hour.
Is a single storey or a wraparound kitchen extension better value?
A plain single storey rear extension is almost always the best value per m² because it uses the simplest structure and the fewest steel beams. A wraparound extension costs more per m² but can transform the layout of a house that is short on side space. Compare them before you commit.
| Single storey rear | Side-return | Wraparound | |
|---|---|---|---|
| Typical size | 12 to 30 m² | 10 to 16 m² | 28 to 40 m² |
| Cost per m² | Lowest | Medium | Highest |
| Planning route | Often permitted development | Often permitted development | Often needs full planning |
| Structural work | One main beam | Beam and boundary wall | Multiple beams, complex |
| Best for | Kitchen-diner on a budget | Terraces with a narrow side passage | Reworking the whole ground floor |
See our guide on single storey versus double storey extensions if you are also weighing up building upwards.
Can you stay in your home during a kitchen extension?
Yes, most households do. The new structure is built outside the existing house, so you keep your kitchen until the final connection. The disruption comes when the old rear wall is opened up, which typically means a temporary kitchen for several weeks. A good builder protects the rest of the house with dust screens and cleans the site daily.
BDC Construction holds 4.94 out of 5 from 79 TrustATrader reviews, built largely on referrals and repeat work. See recent projects across Kent.
How can you keep a kitchen extension on budget?
- Decide the footprint and the glazing early, because changes after the engineer’s drawings are expensive.
- Get a fixed, itemised quote with exclusions listed. Our guide on how to choose a building contractor in Kent shows what to check.
- Set the kitchen budget separately, because it can swing the total by £20,000 or more.
- Ask for a provisional sum list so groundworks risks are visible before you sign.
- Use one main contractor to coordinate the engineer, electrician, plumber and plasterer, so no trade waits on another.
- Agree staged payments tied to completed work, with a retention until snagging is done.
- Read our 12 ways to reduce the cost of a house extension in Kent and use our house extension cost calculator for a first estimate.
Does a kitchen extension add value to your home?
Usually yes. BestBuilders estimates a well-designed kitchen extension adds 60 to 80 per cent of its cost to the value of a home, and it costs far less than moving, which it puts at £25,000 to £60,000 in fees and costs. The return is strongest when the new space creates a proper kitchen-diner and connects to the garden. Local agents give the best view on your street.
Which Kent areas does BDC cover for kitchen extensions?
BDC Construction is based in Maidstone and covers Bearsted, Headcorn, Sevenoaks, Tunbridge Wells and surrounding villages. Every enquiry starts with a planning and structural check, including conservation area and Article 4 status. See the areas we cover across Kent.
The takeaway
Budget £55,000 to £110,000 for a typical fully fitted kitchen extension in Kent in 2026, add 10 to 15 per cent contingency, check permitted development and conservation area rules first, and insist on a fixed, itemised quote.
Planning a kitchen extension in Kent? Talk to a Maidstone builder with 20+ years’ experience. Get a free, no-obligation quote from BDC Construction.
Frequently asked questions
How much does a kitchen extension cost in Kent?
Most fully fitted kitchen extensions in Kent cost £55,000 to £110,000 in 2026. A small 12 to 15 m² rear extension can start around £52,000, while large open-plan schemes with premium kitchens and bi-fold doors can pass £150,000. Kent prices run 25 to 40 per cent above the UK average.
How much does a 20 m² kitchen extension cost?
A 20 m² kitchen-diner in Kent typically costs £69,000 to £112,000 fully fitted, including the kitchen, finishes and fees. The shell alone is roughly £55,000 to £90,000 on the per m² rates above. The final figure depends on ground conditions, steelwork and glazing.
Do I need planning permission for a kitchen extension?
Often no. Many single storey rear extensions are permitted development, up to 3 m deep (semi-detached or terraced) or 4 m (detached), with larger depths under the prior approval scheme. You always need Building Regulations approval. Listed buildings, flats and many conservation areas need separate consent.
How long does a kitchen extension take to build?
Plan on 12 to 16 weeks on site for a typical single storey kitchen extension, plus several weeks for design, engineering and Building Control approval beforehand.
Is VAT charged on a kitchen extension?
Yes. Extensions to an existing home are standard rated, so builders charge 20 per cent VAT on labour and materials. Zero rating applies only to new dwellings. Confirm the position with your accountant.
Is it cheaper to extend or to move house?
Extending is usually cheaper. Moving costs an estimated £25,000 to £60,000 in agent fees, stamp duty and removals before you pay more for a larger house, while an extension adds 60 to 80 per cent of its cost in value and keeps you in a location you already like.