Two-storey extensions in Darwen
We design, get approval for and build two-storey extensions in Darwen and the surrounding area. Choose the type of extension below or book a free site visit.
Darwen at a glance
- Postcode districts
- BB3
- Area
- Lancashire, England
- Price region
- North West England
- Nearest towns
- Blackburn (3.7 miles), Haslingden (5.8 miles), Accrington (5.8 miles), Great Harwood (6.4 miles)
- Distance to Preston
- about 10.8 miles
- Approvals
- Two-storey rear: up to 3 m deep and 7 m from the rear boundary under permitted development. Side, wraparound and front: planning permission.
Around Darwen we also work in Blackburn, Haslingden and Accrington, and across the rest of Lancashire. Postcode district in and near Darwen: BB3.
Extensions available in Darwen
Two-storey rear extensions
Our North West England guide starts at £53,000 for this type.
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Two-storey side extensions
Our North West England guide starts at £82,000 for this type.
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Two-storey wraparound extensions
Design, approvals and build for Darwen homes. Guide from £114,500.
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Part single, part two-storey extensions
Guide from £68,500 in Darwen, including VAT.
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Extensions over a garage
Guide from £30,000 in Darwen, including VAT.
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First-floor extensions
Our North West England guide starts at £24,000 for this type.
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Two-storey extensions for semi-detached houses
Our North West England guide starts at £53,000 for this type.
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Two-storey extensions for detached houses
For homes in Darwen: typical guide from £82,000.
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Kitchen extensions with bedrooms above
Our North West England guide starts at £53,000 (before kitchen units) for this type.
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Extra bedroom and en-suite extensions
Guide from £53,000 (plus en-suite) in Darwen, including VAT.
Learn moreWhich type suits your house?
Start with what you need the space for. Bedrooms and an en-suite upstairs with a bigger kitchen below is the classic two-storey brief, but in Darwen we also design annexes, home offices and bedrooms over garages.
Also available in Lancashire
- Two-storey front extensions
- Two-storey extensions for end-of-terrace houses
- Two-storey annexe extensions
- Garage conversions with a room above
- Two-storey extension plans and drawings
- Planning permission for two-storey extensions
- Structural engineering for two-storey extensions
- Building regulations for two-storey extensions
- Party wall notices for extensions
- Design and build two-storey extensions
Rules for Darwen
Darwen is in England. Two-storey rear: up to 3 m deep and 7 m from the rear boundary under permitted development. Side, wraparound and front: planning permission. Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.
The full England rules explained
Questions about extensions in Darwen
Do you cover Darwen?
Yes. We cover Darwen (BB3) and the surrounding area, including Blackburn and Haslingden. The first site visit is free.
What does a two-storey extension cost in Darwen?
Using our North West England guide, a two-storey rear extension with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) is about £53,000–£72,000 including VAT. An extension over a garage is about £30,000–£43,500.
Which other places near Darwen do you cover?
Everywhere around it, including Blackburn (3.7 miles), Haslingden (5.8 miles) and Accrington (5.8 miles), and the rest of Lancashire.