Extensions in Marlow: design, planning and build
Planning an extension in Marlow? Compare extension types, see guide prices adjusted for Marlow and book a free site visit.
- Postcode districtsSL7
- Price regionSouth East England (×1.12)
- Planning rulesEngland
- Site visitFree, no obligation
Planning rules in Marlow
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 extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a householder planning application.
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 Marlow
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 |
| Conservatory replacement extensions | 14 m² | £33,500 – £43,500 |
| Kitchen extensions | 20 m² | £47,000 – £59,500 |
| Extensions over a garage | 12 m² | £28,000 – £36,500 |
| Single-storey rear extensions | 20 m² | £45,500 – £58,500 |
| Wraparound extensions | 25 m² | £64,000 – £81,500 |
| Orangery extensions | 16 m² | £50,000 – £63,000 |
Which extension suits a Marlow home?
Homes across the South East range from Victorian terraces in the older town centres to large detached houses on the edges, so the right extension type varies street by street.
For many houses here, double-storey extensions, wraparound extensions or orangery extensions gives the most useful space for the budget.
Marlow and surrounding towns
Our survey diary covers Marlow, including SL7. The same team covers High Wycombe (4 miles), Gerrards Cross (9 miles), Amersham (10 miles), Chalfont St Peter (10 miles), Chesham (12 miles), all within easy reach. For homes towards Berkshire, Maidenhead is around 4 miles away.
Extension types and starting prices
- Home office extensions · from £17,500
- Side extensions · from £24,500
- Porch extensions · from £4,450
- Kitchen extensions · from £30,000
- Extension plans and drawings · from £1,300
- Planning permission for extensions · from £350
- Single-storey rear extensions · from £23,500
- Bungalow extensions · from £29,000
- Annexe extensions · from £61,500
- Utility and boot room extensions · from £15,500
- Wraparound extensions · from £40,000
- Conservatory replacement extensions · from £22,000
- Building regulations for extensions · from £1,000
- Side return extensions · from £20,000
- Pitched roof extensions · from £24,500
- Glass box extensions · from £33,500
- Orangery extensions · from £33,500
- Extensions over a garage · from £26,500
- Double-storey extensions · from £42,500
- Flat roof extensions · from £23,500
- Timber frame extensions · from £23,500
- Bedroom extensions · from £29,000
Free site visit
We visit your Marlow home, measure up, talk through what you want and check the planning position.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Questions about extensions in Marlow
How much does an extension cost in Marlow?
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.
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.
Do you handle building regulations?
Yes. We prepare the drawings and calculations, submit them and book inspections, ending with a completion certificate.
Do you cover all of Marlow?
Yes, including the surrounding parts of Buckinghamshire. Site visits are free and there is no obligation.
Book a free site visit in Marlow
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.