Folkestone house extensions
Looking to extend your home in Folkestone? Start here: extension types, guide prices for Folkestone, the planning rules that apply and how a project runs.
- Postcode districtsCT18, CT19, CT20
- Price regionSouth East England (×1.12)
- Planning rulesEngland
- Site visitFree, no obligation
Folkestone and surrounding towns
Site visits are available across Folkestone (CT18, CT19, CT20). Nearby, we also take on projects in Dover (7 miles), Ashford, Kent (13 miles), Deal (14 miles), Canterbury (14 miles), Faversham (20 miles). Hastings, in East Sussex, is roughly 30 miles from Folkestone and also on our list.
Do extensions in Folkestone 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).
Which extension suits a Folkestone home?
In the South East, plenty of houses have already been extended once, which makes checking the remaining permitted development allowance an important early step.
The types we would usually look at first for a home in Folkestone are single-storey rear extensions, wraparound extensions and double-storey extensions, depending on the garden and how the house is laid out.
Guide prices for Folkestone
We publish guide prices so you can budget before anyone visits. For Folkestone they are adjusted by ×1.12, the factor we use across South East England.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Double-storey extensions | 32 m² | £64,500 – £84,500 |
| Side return extensions | 11 m² | £29,500 – £37,000 |
| 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 |
| Extensions over a garage | 12 m² | £28,000 – £36,500 |
Every extension type in Folkestone
- Orangery extensions · from £33,500
- Single-storey rear extensions · from £23,500
- Porch extensions · from £4,450
- Pitched roof extensions · from £24,500
- Annexe extensions · from £61,500
- Side return extensions · from £20,000
- Building regulations for extensions · from £1,000
- Utility and boot room extensions · from £15,500
- Flat roof extensions · from £23,500
- Planning permission for extensions · from £350
- Extensions over a garage · from £26,500
- Home office extensions · from £17,500
- Extension plans and drawings · from £1,300
- Kitchen extensions · from £30,000
- Bungalow extensions · from £29,000
- Side extensions · from £24,500
- Wraparound extensions · from £40,000
- Double-storey extensions · from £42,500
- Glass box extensions · from £33,500
- Conservatory replacement extensions · from £22,000
- Bedroom extensions · from £29,000
- Timber frame extensions · from £23,500
Free site visit
We visit your Folkestone 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
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
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 Folkestone
How much does an extension cost in Folkestone?
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 I need planning permission for an extension in Folkestone?
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.
Do you handle building regulations?
Yes. We prepare the drawings and calculations, submit them and book inspections, ending with a completion certificate.
Book a free site visit in Folkestone
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.