House extensions in March
More space without moving: we plan and build extensions across March, with one team for the drawings, the council and the build.
- Postcode districtsPE15
- Price regionEast of England (×1.06)
- Planning rulesEngland
- Site visitFree, no obligation
Guide prices for March
Every figure below is a guide for March, adjusted for East of England build costs (×1.06) and including VAT. Design and council fees are shown separately on each page.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Orangery extensions | 16 m² | £47,000 – £59,500 |
| Double-storey extensions | 32 m² | £61,000 – £80,000 |
| Side return extensions | 11 m² | £27,500 – £35,000 |
| Single-storey rear extensions | 20 m² | £43,000 – £55,500 |
| Extensions over a garage | 12 m² | £26,500 – £34,500 |
| Kitchen extensions | 20 m² | £44,500 – £56,500 |
| Conservatory replacement extensions | 14 m² | £31,500 – £41,000 |
What works best for March houses?
Across the East of England many houses sit on generous plots, and single-storey and wraparound extensions are a natural fit.
Start by comparing double-storey extensions, single-storey rear extensions and wraparound extensions: between them they cover most of the layouts we see requested for houses like these.
March and surrounding towns
Postcode districts we cover around March include PE15. The same team covers Wisbech (8 miles), Ely (13 miles), Peterborough (14 miles), Huntingdon (19 miles), Cambridge (24 miles), all within easy reach. For homes towards Norfolk, King's Lynn is around 19 miles away.
Approvals for an extension in March
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).
All extension types we build in March
- Double-storey extensions · from £40,000
- Timber frame extensions · from £22,000
- Extension plans and drawings · from £1,250
- Annexe extensions · from £58,000
- Orangery extensions · from £31,500
- Conservatory replacement extensions · from £21,000
- Building regulations for extensions · from £950
- Single-storey rear extensions · from £22,000
- Bedroom extensions · from £27,500
- Side return extensions · from £19,000
- Flat roof extensions · from £22,000
- Wraparound extensions · from £38,000
- Side extensions · from £23,000
- Utility and boot room extensions · from £14,500
- Planning permission for extensions · from £350
- Pitched roof extensions · from £23,500
- Extensions over a garage · from £25,000
- Home office extensions · from £16,500
- Bungalow extensions · from £27,500
- Porch extensions · from £4,200
- Glass box extensions · from £31,500
- Kitchen extensions · from £28,500
Free site visit
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
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
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Questions about extensions in March
How much does an extension cost in March?
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.
Do you handle building regulations?
Yes. We prepare the drawings and calculations, submit them and book inspections, ending with a completion certificate.
Can I get a price before anyone visits?
Yes. This page shows guide prices adjusted for March, and the guide-price tool gives a range for your own size and finish in about a minute.
How long does an extension take in March?
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.
Book a free site visit in March
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.