Welwyn Garden City, Hertfordshire
Kitchen-diner rear extension in Welwyn Garden City
Thinking about a kitchen-diner rear extension in Welwyn Garden City? An open-plan kitchen, dining and family room that opens straight onto the garden. Our team handles the drawings, the planning route and the build, and your contract is with one company throughout.
Welwyn Garden City is covered from our Hertfordshire round, including AL7 and AL8. We usually keep the working kitchen where the old one was and put the dining table in the new space by the doors, which suits most Welwyn Garden City homes.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a kitchen-diner rear extension cost in Welwyn Garden City?
A kitchen-diner rear extension in Welwyn Garden City is priced at £2,010–£3,290 per square metre including VAT as a guide, before kitchen fit-out and fees. East of England prices run slightly above our West Midlands baseline; clay soils near trees are the main foundation variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £24,000–£39,500 |
| 4 m wide × 5 m deep (20 m²) | £40,500–£65,500 |
| 4 m wide × 6 m deep (24 m²) | £48,500–£79,000 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a kitchen-diner rear extension in Welwyn Garden City?
The planning route for a kitchen-diner rear extension in Welwyn Garden City is set by England's householder rules and your council.
English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres within 2 metres of a boundary.
If 3 or 4 metres is not enough, England's prior approval route allows 6 metres on a terraced or semi-detached house and 8 metres on a detached house for a single-storey rear extension. Neighbours are consulted, the council decides within 42 days, and the fee is £249, rising to £310 from 8 December 2026.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. Before any drawing we look up the property's history with the council, because earlier extensions and removed rights change the answer.
What are homes in Welwyn Garden City like to extend?
Welwyn Garden City mixes Victorian terraces with 1930s semis, so both side returns and full-width kitchen extensions suit houses here. For Welwyn Garden City kitchens we plan the extraction route and the island drainage before the slab is poured, so nothing has to be chased in later.
How a kitchen-diner rear extension in Welwyn Garden City comes together
Look round and measure
A free visit to see the back of the house, measure it, check the drains and boundaries and hear what you need.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
Paperwork handled
Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Kitchen-diner rear extensions near Welwyn Garden City
We also build kitchen-diner rear extensions in nearby Hatfield (2.8 miles) and Codicote (3.6 miles).
- Kitchen-diner rear extension in Hatfield
- Kitchen-diner rear extension in Codicote
- Kitchen-diner rear extension in Hertford
- Kitchen-diner rear extension in St Albans
- Kitchen-diner rear extension in Harpenden
Other work in Welwyn Garden City:
FAQ
Kitchen-diner rear extension questions in Welwyn Garden City
Can you match the brick or stone on my Welwyn Garden City house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
How much does a kitchen-diner rear extension cost in Welwyn Garden City?
As a guide, £2,010–£3,290 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £24,000–£39,500 at that rate. Your written price follows the survey.
How big should a kitchen-diner be?
Around 25 to 35 m² for the combined kitchen, dining and seating areas suits most family homes. Your survey shows what fits the house.
Do I need planning permission for a rear extension in Welwyn Garden City?
Often not for a single-storey rear extension of up to 3 metres (4 metres on a detached house) under permitted development, or up to 6 or 8 metres with prior approval, unless the house is in a conservation area or its rights have been removed.
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.
How long does a rear extension take to build in Welwyn Garden City?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.