Redhill house extensions
We design and build house extensions for homes in Redhill and the surrounding Surrey area, with guide prices adjusted for the region.
- Postcode districtsRH1, RH2
- Price regionSouth East England (×1.12)
- Planning rulesEngland
- Site visitFree, no obligation
Areas we cover around Redhill
Site visits are available across Redhill (RH1, RH2). The same team covers Reigate (2 miles), Horley (5 miles), Caterham (5 miles), Banstead (6 miles), Epsom (8 miles), all within easy reach. Coulsdon, in Greater London, is roughly 6 miles from Redhill and also on our list.
What works best for Redhill houses?
The South East has a broad mix of 1930s semis, post-war estates, newer developments and period cottages, and many houses have enough garden for a generous rear extension.
Depending on the plot, orangery extensions and single-storey rear extensions are often the strongest options, with double-storey extensions worth considering where there is room.
Guide prices for Redhill
Prices on this page use our South East England factor of ×1.12, include VAT at 20% and cover the build; your written price follows a survey and agreed drawings.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Double-storey extensions | 32 m² | £64,500 – £84,500 |
| Orangery extensions | 16 m² | £50,000 – £63,000 |
| Side return extensions | 11 m² | £29,500 – £37,000 |
| Conservatory replacement extensions | 14 m² | £33,500 – £43,500 |
| Single-storey rear extensions | 20 m² | £45,500 – £58,500 |
| Wraparound extensions | 25 m² | £64,000 – £81,500 |
| Extensions over a garage | 12 m² | £28,000 – £36,500 |
Do extensions in Redhill need planning permission?
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).
Choose an extension type
- Planning permission for extensions · from £350
- Side return extensions · from £20,000
- Building regulations for extensions · from £1,000
- Extension plans and drawings · from £1,300
- Double-storey extensions · from £42,500
- Orangery extensions · from £33,500
- Single-storey rear extensions · from £23,500
- Porch extensions · from £4,450
- Kitchen extensions · from £30,000
- Glass box extensions · from £33,500
- Pitched roof extensions · from £24,500
- Bungalow extensions · from £29,000
- Conservatory replacement extensions · from £22,000
- Home office extensions · from £17,500
- Extensions over a garage · from £26,500
- Timber frame extensions · from £23,500
- Utility and boot room extensions · from £15,500
- Bedroom extensions · from £29,000
- Annexe extensions · from £61,500
- Wraparound extensions · from £40,000
- Side extensions · from £24,500
- Flat roof extensions · from £23,500
Free site visit
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Questions about extensions in Redhill
How much does an extension cost in Redhill?
Using our South East England factor (×1.12), a standard-spec single-storey extension of 20 m² is a guide £45,500 to £58,500 including VAT, and a 32 m² two-storey extension £64,500 to £84,500. Your written price follows the survey.
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.
How long does an extension take in Redhill?
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.
Do I need planning permission for an extension in Redhill?
Not always. It depends on the size, position and your property's history. Many single-storey rear extensions in England are permitted development or can use prior approval.
Book a free site visit in Redhill
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.