Home office extensions for homes in Dartford
A home office extension in Dartford 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 DartfordFrom £17,500 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time8–12 weeks on site
- Postcode districtsDA1, DA2, DA9

Local to Dartford
Postcode districts we cover around Dartford include DA1, DA2, DA9. Neighbouring towns we cover include Swanley (4 miles), Gravesend (7 miles), Strood (12 miles), Sevenoaks (12 miles).
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.
What should I budget for a home office extension in Dartford?
For Dartford we adjust our national guide rates by ×1.12, the factor we use for South East England. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Dartford: £2,070 to £3,810 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 3.2 m 8 m² | £17,500 – £21,500 | £19,000 – £24,500 | £24,000 – £30,500 |
| 3 m × 3.6 m 11 m² | £22,500 – £27,500 | £26,000 – £33,500 | £33,000 – £42,000 |
| 3 m × 5 m 15 m² | £31,000 – £37,000 | £36,000 – £45,500 | £45,000 – £57,500 |
For a figure based on your own dimensions, use our guide-price tool.
Is a home office extension right for your house?
- Households that need a second quiet room
- People who work from home most of the week
- Homes where a loft or garden room is not practical
Planning and approvals in Dartford
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 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).
What happens next
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 Dartford home, measure up, talk through what you want and check the planning position.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
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.
Home office extension questions answered
Will my neighbours in Dartford be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Do I need building regulations approval in Dartford?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
How long does a home office extension take to build in Dartford?
On site, typically 8 to 12 weeks once approvals are in place. Before that, allow 4–10 weeks design and approvals.
How much does a home office extension cost?
Our guide range is about £2,070 to £3,810 per m² including VAT. An 11 m² standard-spec office is typically £26,000 to £33,500 in Dartford.
Is an attached office better than a garden office?
An attached office shares the house heating and broadband, adds floor area to the home, and needs no garden path in the rain. A garden building can be cheaper and quicker but is a separate structure.
Book a free site visit in Dartford
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.