Welwyn Garden City, Hertfordshire
Bungalow rear extension in Welwyn Garden City
Bungalow rear extension in Welwyn Garden City: single-storey rear extensions that keep everything on one level. We measure the house, show you what the rules allow, price it in writing and build it.
We cover Welwyn Garden City (AL7 and AL8) as part of our Hertfordshire work. For bungalows in Hertfordshire, a rear extension is the usual way to add space without adding stairs.
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 bungalow rear extension cost in Welwyn Garden City?
A bungalow rear extension in Welwyn Garden City is priced at £1,960–£3,180 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) | £23,500–£38,000 |
| 4 m wide × 6 m deep (24 m²) | £47,000–£76,500 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a bungalow rear extension in Welwyn Garden City?
The planning route for a bungalow rear extension in Welwyn Garden City is set by England's householder rules and your council.
Under England's householder permitted development rules you can usually add 3 metres at the back of an attached house, or 4 metres on a detached house, without a planning application, as long as the extension stays under 4 metres high and its eaves stay under 3 metres where it is within 2 metres of a boundary.
England also has the larger home extension route: a single-storey rear extension of up to 6 metres on an attached house or 8 metres on a detached house, after prior approval from the council. The council notifies your neighbours and has 42 days to decide; the fee is £249 (£310 for applications made from 8 December 2026). The route is not available on designated land such as conservation areas.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Welwyn Garden City like to extend?
Post-war semis and newer estates are typical of Welwyn Garden City, and many have room for a full-width extension. Shrinkable clay is common in the East of England, so foundations near trees and hedges are designed to NHBC-style depth guidance.
How a bungalow rear extension in Welwyn Garden City comes together
Free site visit
We measure the house and garden, look at the back wall, drainage and boundaries, and talk through what you want from the space.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
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.
Bungalow rear extensions near Welwyn Garden City
Close by, we work in Hatfield, about 2.8 miles away, and Codicote, about 3.6 miles away.
- Bungalow rear extension in Hatfield
- Bungalow rear extension in Codicote
- Bungalow rear extension in Hertford
- Bungalow rear extension in St Albans
- Bungalow rear extension in Harpenden
Other work in Welwyn Garden City:
FAQ
Bungalow 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.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
Do I need to move out?
Rarely; the opening into the bungalow is made late in the build.
Who will build my extension?
Vetted building teams working under contract to us. Your contract is with S&K Property Investments and Improvement Ltd for the design and the build.
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.
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.