Two-storey wraparound extensions in Darwen

Useful details for planning a two-storey wraparound extension in Darwen.

Postcode districts: BB3
County / area: Lancashire, England
Price region: North West England
Guide price: £114,500–£157,000 (£2,040–£2,800 per m²)
Approval route: Planning permission is needed: the side part takes it outside permitted development in England.
Nearest towns: Blackburn (3.7 miles), Haslingden (5.8 miles), Accrington (5.8 miles)
Distance to Preston: about 10.8 miles
First visit: Free, no obligation

About a two-storey wraparound extension

A two-storey wraparound extension is an L-shaped addition that extends both the side and the rear of your house, on two floors. It gives one of the largest gains in floor space of any extension, typically a big open-plan kitchen and living area below and two or more bedrooms or bathrooms above. In England it needs planning permission, because the side part is more than one storey.

Darwen sits about 10.8 miles from Preston. Closer to home, Blackburn is 3.7 miles away and Haslingden 5.8 miles.

What it costs in Darwen

Using our North West England rates, a two-storey wraparound extension with an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space) comes to about £114,500–£157,000, including VAT. Bigger or more glazed designs cost more per m². These are guides, not quotes. Ground conditions, steelwork and access can move the figure either way.

Spec	Per m²	An L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space)
Essential	£1,880–£2,580 per m²	£105,000–£144,500
Standard	£2,040–£2,800 per m²	£114,500–£157,000
Premium	£2,450–£3,360 per m²	£137,500–£188,500

Planning and building regulations in Darwen

In England, a two-storey wraparound extension needs householder planning permission, because any extension beyond a side wall must be single storey to be permitted development. The application costs £548 (or £575 for applications made from 8 December 2026). Councils weigh the side part against the street scene and the rear part against neighbours' light and outlook, and should decide within 8 weeks of validation.

Approval in England: 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.

Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.

Design points for Darwen homes

Phasing the build

A wraparound touches two sides of the house at once, so the kitchen and often the rear rooms are out of use for part of the build. We plan the sequence so you keep a working kitchen and bathroom for as long as possible, or advise when moving out briefly makes sense.

Daylight to the middle

A deep L-shaped plan can leave the middle of the ground floor dark, because the old rear rooms are now enclosed. We use wide rear openings, a well-placed stair and, where part of the extension is single storey, roof lights, while keeping total glazing within the Part L allowance.

How we'd run your project

Measure and listen
A visit to Darwen to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Get it approved
Once you're happy with the design we submit it to the council for Darwen and deal with any questions from the planning officer.
Engineer it
Foundations sized for two floors, steels for any openings, and building control approval, all before anyone starts on site.
Build it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.

Questions about two-storey wraparound extensions in Darwen

How much does a two-storey wraparound extension cost in Darwen?

Our guide for North West England, which covers Darwen, is £2,040–£2,800 per m² including VAT. A typical project with an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space) comes to about £114,500–£157,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

How long does a two-storey wraparound extension take?

Allow 4 to 8 weeks for survey and design, then the approval period (councils should decide householder applications within 8 weeks of validation), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.

Do I need planning permission for a two-storey wraparound extension in Darwen?

Darwen is in England, so England planning rules apply. Planning permission is needed: the side part takes it outside permitted development in England. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.

Can a wraparound extension be part single, part two-storey?

Yes. Many wraparounds keep the rear part single storey with roof lights over the kitchen and put the two-storey part to the side. This can reduce the effect on neighbours and the cost. We set out both options at the design stage, so you can compare floor space against price before choosing.

Does a wraparound extension need steel?

Almost always. Opening the corner of the house and the old rear wall to make one open-plan space means steel beams, and often a steel post or frame at the outside corner. The structural engineer sizes these, and the steel is ordered once the design is fixed, which is one reason a wraparound needs careful sequencing.

Nearby

Other towns near Darwen:

Other extensions in Darwen

All two-storey extension services in Darwen · Two-storey wraparound extensions across Lancashire

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