Double-storey extensions across Dover
A double-storey extension in Dover starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in DoverFrom £42,500 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsCT16, CT17
What should I budget for a double-storey extension in Dover?
Prices below are for Dover, using the South East England factor of ×1.12. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Dover: £1,740 to £3,360 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m, two floors 24 m² | £42,500 – £51,000 | £48,000 – £63,500 | £61,500 – £81,000 |
| 4 m × 4 m, two floors 32 m² | £55,500 – £66,500 | £64,500 – £84,500 | £82,000 – £108,000 |
| 4 m × 6 m, two floors 48 m² | £83,000 – £99,500 | £96,500 – £126,500 | £123,500 – £161,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
What is included
- Foundations sized for two floors
- Householder planning application where needed
- Building regulations drawings and structural design
- Measured survey, design and planning drawings
- Breaking through at both levels, stairs and landing changes where needed
- Ground and first floor structure, roof tied into the existing roof
Do I need planning permission in Dover?
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 over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
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).
Extensions in and around Dover
We cover Dover and the postcode districts CT16, CT17. Neighbouring towns we cover include Folkestone (7 miles), Deal (8 miles), Canterbury (15 miles), Ramsgate (15 miles).
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.
How the project works
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
We visit your Dover home, measure up, talk through what you want and check the planning position.
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
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.
Your questions about a double-storey extension in Dover
Who do I contract with for a double-storey extension in Dover?
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.
How long does a double-storey extension take to build in Dover?
On site, typically 16 to 24 weeks once approvals are in place. Before that, allow 8–16 weeks design and approvals.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Dover, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do I need a Party Wall Agreement?
If you are in England or Wales and the work involves a shared wall or digging foundations close to a neighbour, the Party Wall etc. Act 1996 applies and notices must be served before work starts. We tell you which notices are needed.
Is a two-storey extension cheaper per square metre?
Usually. Our guide range is about £1,740 to £3,360 per m² of new floor area including VAT, compared with £1,960 to £3,810 per m² for single-storey work, because the foundations and roof are shared across two floors.
Book a free site visit in Dover
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.