Bungalow extensions in Chelmsford: design, approvals and build
Our design and build teams take on bungalow extensions in Chelmsford, from the first measured survey through planning and building control to the finished room.
- Guide price in ChelmsfordFrom £27,500 inc VAT
- PlanningSingle storey often permitted development
- Build time10–18 weeks on site
- Postcode districtsCM1, CM2

Guide prices for Chelmsford
Prices below are for Chelmsford, using the East of England factor of ×1.06. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Chelmsford: £1,860 to £3,600 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 5 m 15 m² | £27,500 – £33,500 | £32,500 – £42,500 | £41,000 – £54,500 |
| 4 m × 6 m 24 m² | £44,500 – £53,500 | £52,000 – £67,500 | £66,000 – £86,500 |
| L-shape 35 m² | £64,500 – £78,000 | £76,000 – £98,500 | £96,000 – £126,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
Planning rules that apply in Chelmsford
In England a single-storey extension to a bungalow follows the normal permitted development limits (3 m or 4 m, or 6 m and 8 m through prior approval). Adding a first floor always needs planning permission.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
What is included
- Level thresholds and accessible layouts
- Planning application where needed
- Structural survey before any upward extension
- Roof designs that tie into the existing hipped or gable roof
- Single-storey extension options assessed first
Local to Chelmsford
Site visits are available across Chelmsford (CM1, CM2). The same team covers Billericay (8 miles), Witham (9 miles), Maldon (9 miles), Wickford (9 miles), all within easy reach.
Just over the Hertfordshire border, Bishop's Stortford is about 16 miles away. Across the East of England many houses sit on generous plots, and single-storey and wraparound extensions are a natural fit.
What happens next
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Your questions about a bungalow extension in Chelmsford
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Chelmsford, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do I need building regulations approval in Chelmsford?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Will my neighbours in Chelmsford be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Is it better to extend sideways or upwards?
Sideways and rearwards is usually simpler, cheaper and keeps single-level living. Upwards saves garden but means stairs, more structure and planning permission.
How much does a bungalow extension cost?
Our guide range for single-storey work is about £1,860 to £3,600 per m² including VAT. Going upwards is priced after a structural survey.
Book a free site visit in Chelmsford
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.