Ampthill annexe extensions, designed and built
We design and build annexe extensions for houses in Ampthill, with a written price once the survey and design are done and one point of contact throughout.
- Guide price in AmpthillFrom £58,000 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsMK45
Planning and approvals in Ampthill
In England an annexe that stays part of the household and connects to the house is assessed as an extension, but its size usually takes it beyond permitted development, so a householder application describing the ancillary use is the normal route.
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.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
Who an annexe extension suits
- Homes with a large side or rear garden
- Relatives who need support close by
- Multi-generational families
What should I budget for an annexe extension in Ampthill?
Prices below are for Ampthill, 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 Ampthill: £2,120 to £4,030 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Studio annexe 25 m² | £58,000 – £73,000 | £63,500 – £79,500 | £79,500 – £101,000 |
| One-bedroom annexe 35 m² | £74,000 – £93,000 | £89,000 – £111,500 | £111,000 – £141,000 |
| Larger annexe 45 m² | £95,000 – £119,500 | £114,000 – £143,500 | £143,000 – £181,500 |
For a figure based on your own dimensions, use our guide-price tool.
Extensions in and around Ampthill
Across MK45, we can visit, measure and advise. Neighbouring towns we cover include Kempston (6 miles), Bedford (8 miles), Dunstable (10 miles), Leighton Buzzard (10 miles).
The East of England mixes market-town terraces, inter-war semis and modern estates. Clay soils are common in parts of the region, which can affect foundation design.
From first visit to completion
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Your questions about an annexe extension in Ampthill
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Ampthill, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
How long does an annexe extension take to build in Ampthill?
On site, typically 16 to 24 weeks once approvals are in place. Before that, allow 10–16 weeks design and approvals.
Do you cover all of Ampthill?
Yes. We cover Ampthill and the surrounding parts of Bedfordshire. Site visits are free and there is no obligation.
Can the annexe have its own front door?
Yes, many do, but it should still connect to the main house to stay clearly part of it.
How much does an annexe extension cost?
Our guide range is about £2,120 to £4,030 per m² including VAT. A one-bedroom annexe of about 35 m² is typically £89,000 to £111,500 at standard spec in Ampthill.
Book a free site visit in Ampthill
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.