Extending your home in Kempston
We design and build house extensions for homes in Kempston and the surrounding Bedfordshire area, with guide prices adjusted for the region.
- Postcode districtsMK40, MK42
- Price regionEast of England (×1.06)
- Planning rulesEngland
- Site visitFree, no obligation
Popular extension prices in Kempston
We publish guide prices so you can budget before anyone visits. For Kempston they are adjusted by ×1.06, the factor we use across East of England.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Extensions over a garage | 12 m² | £26,500 – £34,500 |
| Conservatory replacement extensions | 14 m² | £31,500 – £41,000 |
| Wraparound extensions | 25 m² | £60,500 – £77,000 |
| Single-storey rear extensions | 20 m² | £43,000 – £55,500 |
| Double-storey extensions | 32 m² | £61,000 – £80,000 |
Planning and building control in Kempston
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
In England a two-storey rear extension is permitted development only if it projects no more than 3 m from the original rear wall, sits at least 7 m from the rear boundary, matches the roof pitch and uses obscure, non-opening side windows upstairs. Most two-storey extensions therefore go through a householder planning application, which costs £548 from 1 April 2026 and normally takes about 8 weeks.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
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).
What works best for Kempston houses?
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.
For many houses here, wraparound extensions, double-storey extensions or single-storey rear extensions gives the most useful space for the budget.
Kempston and surrounding towns
We cover Kempston and the postcode districts MK40, MK42. The same team covers Bedford (2 miles), Ampthill (6 miles), Leighton Buzzard (15 miles), Dunstable (16 miles), Luton (17 miles), all within easy reach. Just over the Buckinghamshire border, Milton Keynes is about 12 miles away.
Choose an extension type
- Extension plans and drawings · from £1,250
- Timber frame extensions · from £22,000
- Bungalow extensions · from £27,500
- Bedroom extensions · from £27,500
- Wraparound extensions · from £38,000
- Annexe extensions · from £58,000
- Side return extensions · from £19,000
- Flat roof extensions · from £22,000
- Kitchen extensions · from £28,500
- Porch extensions · from £4,200
- Planning permission for extensions · from £350
- Orangery extensions · from £31,500
- Double-storey extensions · from £40,000
- Utility and boot room extensions · from £14,500
- Glass box extensions · from £31,500
- Building regulations for extensions · from £950
- Home office extensions · from £16,500
- Pitched roof extensions · from £23,500
- Conservatory replacement extensions · from £21,000
- Extensions over a garage · from £25,000
- Single-storey rear extensions · from £22,000
- Side extensions · from £23,000
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
The build is managed from start to finish, inspected at each stage and signed off on completion.
Questions about extensions in Kempston
How much does an extension cost in Kempston?
Using our East of England factor (×1.06), a standard-spec single-storey extension of 20 m² is a guide £43,000 to £55,500 including VAT, and a 32 m² two-storey extension £61,000 to £80,000. Your written price follows the survey.
How long does an extension take in Kempston?
Usually 2 to 4 months of design and approvals, then 10 to 16 weeks on site for a single-storey extension or 16 to 24 weeks for two storeys.
Who do I contract with?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Will my neighbours need to be told?
If you apply for planning or prior approval the council notifies them, and in England party wall notices may be needed for work near a shared boundary.
Can I get a price before anyone visits?
Yes. This page shows guide prices adjusted for Kempston, and the guide-price tool gives a range for your own size and finish in about a minute.
Book a free site visit in Kempston
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.