House extensions in Mitcham
More space without moving: we plan and build extensions across Mitcham, with one team for the drawings, the council and the build.
- Postcode districtsCR4, SM4, SM5, SW16, SW17, SW19
- Price regionLondon (×1.3)
- Planning rulesEngland
- Site visitFree, no obligation
Covering Mitcham and nearby
Site visits are available across Mitcham (CR4, SM4, SM5, SW16, SW17, SW19). Nearby, we also take on projects in Morden (1 mile), Tooting (2 miles), Wimbledon (2 miles), Streatham (2 miles), Norbury (2 miles). Ewell, in Surrey, is roughly 5 miles from Mitcham and also on our list.
Choosing the right extension in Mitcham
Across London, terraced houses with narrow side returns and tight access are the norm, which shapes everything from party wall notices to how materials reach the back garden.
Depending on the plot, glass box extensions and kitchen extensions are often the strongest options, with side return extensions worth considering where there is room.
Planning and building control in Mitcham
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 single-storey side return infill is often permitted development if it stays within the height limits and is no wider than half the width of the original house. Conservation areas, listed buildings and flats always need an application, and the boundary wall usually brings in the Party Wall Act.
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).
Popular extension prices in Mitcham
Prices on this page use our London factor of ×1.3, 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) |
|---|---|---|
| Extensions over a garage | 12 m² | £32,500 – £42,500 |
| Side return extensions | 11 m² | £34,000 – £43,000 |
| Double-storey extensions | 32 m² | £74,500 – £98,000 |
| Wraparound extensions | 25 m² | £74,500 – £94,500 |
| Orangery extensions | 16 m² | £58,000 – £73,000 |
Extension types and starting prices
- Extension plans and drawings · from £1,550
- Side extensions · from £28,500
- Side return extensions · from £23,000
- Bedroom extensions · from £33,500
- Flat roof extensions · from £27,000
- Bungalow extensions · from £34,000
- Pitched roof extensions · from £28,500
- Building regulations for extensions · from £1,150
- Conservatory replacement extensions · from £26,000
- Kitchen extensions · from £35,000
- Timber frame extensions · from £27,000
- Annexe extensions · from £71,500
- Utility and boot room extensions · from £18,000
- Orangery extensions · from £39,000
- Single-storey rear extensions · from £27,000
- Extensions over a garage · from £31,000
- Glass box extensions · from £39,000
- Double-storey extensions · from £49,000
- Porch extensions · from £5,200
- Home office extensions · from £20,500
- Wraparound extensions · from £46,500
- Planning permission for extensions · from £450
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
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Questions about extensions in Mitcham
How much does an extension cost in Mitcham?
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.
Can I get a price before anyone visits?
Yes. This page shows guide prices adjusted for Mitcham, and the guide-price tool gives a range for your own size and finish in about a minute.
Do you cover all of Mitcham?
Yes, including the surrounding parts of Greater London. Site visits are free and there is no obligation.
How long does an extension take in Mitcham?
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 Mitcham
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.