Home extensions in Darwen
Planning an extension in Darwen? Compare extension types, see guide prices adjusted for Darwen and book a free site visit.
- Postcode districtsBB3
- Price regionNorth West England (×0.95)
- Planning rulesEngland
- Site visitFree, no obligation
What works best for Darwen houses?
Across the North West, terraced houses with small rear yards suit compact rear and side return extensions, while suburban semis have room for more.
Start by comparing single-storey rear extensions, side return extensions and kitchen extensions: between them they cover most of the layouts we see requested for houses like these.
Darwen extension prices at a glance
Use these Darwen guide prices to sense-check a budget; the guide-price tool narrows them to your own size, and the site visit turns them into a written figure.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Kitchen extensions | 20 m² | £39,500 – £50,500 |
| Single-storey rear extensions | 20 m² | £38,500 – £49,500 |
| Extensions over a garage | 12 m² | £23,500 – £31,000 |
| Double-storey extensions | 32 m² | £54,500 – £71,500 |
| Orangery extensions | 16 m² | £42,500 – £53,500 |
| Side return extensions | 11 m² | £25,000 – £31,500 |
Approvals for an extension in Darwen
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.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
Where we work near Darwen
We cover Darwen and the postcode districts BB3. The same team covers Blackburn (4 miles), Accrington (6 miles), Chorley (7 miles), Rawtenstall (7 miles), Leyland (9 miles), all within easy reach. Horwich, in Greater Manchester, is roughly 8 miles from Darwen and also on our list.
Extension types and starting prices
- Flat roof extensions · from £19,500
- Glass box extensions · from £28,500
- Double-storey extensions · from £36,000
- Single-storey rear extensions · from £19,500
- Side return extensions · from £17,000
- Annexe extensions · from £52,000
- Home office extensions · from £15,000
- Planning permission for extensions · from £300
- Conservatory replacement extensions · from £19,000
- Bedroom extensions · from £24,500
- Pitched roof extensions · from £21,000
- Extensions over a garage · from £22,500
- Bungalow extensions · from £24,500
- Side extensions · from £20,500
- Porch extensions · from £3,800
- Orangery extensions · from £28,500
- Utility and boot room extensions · from £13,000
- Kitchen extensions · from £25,500
- Timber frame extensions · from £19,500
- Extension plans and drawings · from £1,100
- Wraparound extensions · from £34,000
- Building regulations for extensions · from £850
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
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
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 Darwen
How much does an extension cost in Darwen?
Using our North West England factor (×0.95), a standard-spec single-storey extension of 20 m² is a guide £38,500 to £49,500 including VAT, and a 32 m² two-storey extension £54,500 to £71,500. 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 Darwen?
Yes, including the surrounding parts of Lancashire. Site visits are free and there is no obligation.
Will my neighbours need to be told?
If you apply for planning or prior approval the council notifies them, and in England party wall notices may be needed for work near a shared boundary.
Book a free site visit in Darwen
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.