Extending your home in Beckenham
From a small utility to a two-storey addition, we take on house extensions throughout Beckenham, starting with a free visit and a planning check.
- Postcode districtsBR1, BR3, SE6, SE20, SE25, SE26
- Price regionLondon (×1.3)
- Planning rulesEngland
- Site visitFree, no obligation
What works best for Beckenham houses?
London's housing is dominated by Victorian and Edwardian terraces, many with a rear outrigger and a side return, and 1930s semis in the outer boroughs. Conservation areas are common, so the planning check comes first.
Depending on the plot, kitchen extensions and glass box extensions are often the strongest options, with wraparound extensions worth considering where there is room.
What extensions cost in Beckenham
Every figure below is a guide for Beckenham, adjusted for London build costs (×1.3) and including VAT. Design and council fees are shown separately on each page.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Side return extensions | 11 m² | £34,000 – £43,000 |
| Single-storey rear extensions | 20 m² | £53,000 – £68,000 |
| Conservatory replacement extensions | 14 m² | £39,000 – £50,500 |
| Orangery extensions | 16 m² | £58,000 – £73,000 |
| Kitchen extensions | 20 m² | £54,500 – £69,000 |
| Wraparound extensions | 25 m² | £74,500 – £94,500 |
| Double-storey extensions | 32 m² | £74,500 – £98,000 |
Approvals for an extension in Beckenham
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.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
Areas we cover around Beckenham
Our survey diary covers Beckenham, including BR1, BR3, SE6, SE20, SE25, SE26. Nearby, we also take on projects in South Norwood (2 miles), Catford (3 miles), Upper Norwood (3 miles), Croydon (4 miles), Brockley (4 miles). Just over the Kent border, Swanley is about 9 miles away.
Every extension type in Beckenham
- Bungalow extensions · from £34,000
- Conservatory replacement extensions · from £26,000
- Bedroom extensions · from £33,500
- Planning permission for extensions · from £450
- Porch extensions · from £5,200
- Kitchen extensions · from £35,000
- Single-storey rear extensions · from £27,000
- Orangery extensions · from £39,000
- Extensions over a garage · from £31,000
- Side return extensions · from £23,000
- Glass box extensions · from £39,000
- Annexe extensions · from £71,500
- Wraparound extensions · from £46,500
- Side extensions · from £28,500
- Building regulations for extensions · from £1,150
- Pitched roof extensions · from £28,500
- Extension plans and drawings · from £1,550
- Timber frame extensions · from £27,000
- Double-storey extensions · from £49,000
- Utility and boot room extensions · from £18,000
- Home office extensions · from £20,500
- Flat roof extensions · from £27,000
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 produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Questions about extensions in Beckenham
How much does an extension cost in Beckenham?
Using our London factor (×1.3), a standard-spec single-storey extension of 20 m² is a guide £53,000 to £68,000 including VAT, and a 32 m² two-storey extension £74,500 to £98,000. 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.
Do I need planning permission for an extension in Beckenham?
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.
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.
Book a free site visit in Beckenham
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.