What is a kitchen extension?
A kitchen extension is an extension designed around a new kitchen, usually an open-plan kitchen, dining and family space at the back of the house. We build the extension and fit the kitchen as one project, so plumbing, electrics and lighting are planned around the layout from the start.
How much does a kitchen extension cost in Hertfordshire?
In Hertfordshire, a kitchen extension typically costs £2,400–£3,600 per m² including a mid-range kitchen, including VAT at 20% (standard rate). For a typical 22 m² project that is roughly £53,000–£79,000. We start from a UK-wide guide and adjust it for the East of England, where labour and materials are typically about 6% above average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (15 m²) | £36,000–£54,000 |
| Typical project (22 m²) | £53,000–£79,000 |
| Larger project (31 m²) | £74,500–£111,500 |
| Rate per m² | £2,400–£3,600 |
The biggest cost drivers are:
- Glazing and roof lanterns
- Underfloor heating and flooring
- Kitchen units, worktops and appliances
- Who supplies the kitchen
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a kitchen extension in Hertfordshire?
Approvals for a kitchen extension in Hertfordshire follow the rules for England. In England a single-storey rear extension is often permitted development: broadly up to 3 metres deep on a semi-detached or terraced house and 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres within 2 metres of a boundary, and covering no more than half the garden. The larger home extension scheme allows up to 6 or 8 metres if you notify the council first and neighbours have a chance to comment. In conservation areas, National Parks and National Landscapes the larger home extension route, side extensions and cladding are not permitted development. Flats and houses whose rights have been removed need a planning application, and listed buildings need listed building consent.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
On a typical kitchen extension we handle:
- Kitchen fitting, worktops and splashbacks
- Electrics, lighting plan and sockets
- Flooring and decoration
- Kitchen layout planned alongside the extension design
- Extraction ducted to outside
- Drainage and water supply positioned for the sink and appliances
How long does it take?
Allow 11 to 16 weeks on site, including kitchen fitting. Allow time beforehand for drawings and approvals, usually 6 to 12 weeks.
Building in Hertfordshire
Many towns in the East of England have estates built since the 1970s, where garage conversions and rear extensions are popular.
Towns we cover in Hertfordshire include Watford, Hemel Hempstead, Stevenage, St Albans, Welwyn Garden City and Cheshunt.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about kitchen extensions in Hertfordshire
Do you build kitchen extensions in Hertfordshire?
Yes. We build kitchen extensions across Hertfordshire, including postcodes AL1, AL10, AL2, AL3 and AL4. Every project starts with a free home visit.
Do I need extraction to outside?
Building regulations require kitchen extract ventilation. Ducting to an outside wall is the most effective option and is planned during the build.
How much does a kitchen extension cost in Hertfordshire?
In Hertfordshire, a kitchen extension typically costs £2,400–£3,600 per m² including a mid-range kitchen, including VAT at 20% (standard rate). A typical 22 m² project comes to roughly £53,000–£79,000. Your fixed price depends on the survey and drawings.
Should the kitchen be designed before the extension?
Yes. Knowing where the sink, hob and island will go lets us place drains, ducting, sockets and windows correctly during the build.
Will I need planning permission?
The same rules apply as for any extension. Many single-storey kitchen extensions are permitted development; larger or wraparound designs need an application.