Two-storey wraparound extensions in Blackburn

The basics for Blackburn at a glance.

Postcode districts: BB1 and BB2
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: Darwen (3.7 miles), Great Harwood (3.9 miles), Accrington (5.1 miles)
Distance to Preston: about 9.1 miles
First visit: Free, no obligation

About a two-storey wraparound extension

A two-storey wraparound extension suits a house with space both beside it and behind it, where you want to transform the layout rather than add a single room. You get one design for the whole L-shape, the planning application, structural design for the corner and the openings into the house, building regulations approval and the build, managed by us and carried out by vetted teams working under S&K.

We cover postcode districts BB1 and BB2 in and around Blackburn, along with neighbouring Darwen, Great Harwood and Accrington.

What it costs in Blackburn

Most of the cost of a two-storey wraparound extension is set by its size and specification. For Blackburn and the rest of North West England, our guide is £2,040–£2,800 per m² including VAT, so about £114,500–£157,000 for an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space). 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 Blackburn

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 Blackburn homes

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.

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.

How we'd run your project

Free site visit
We visit your home in Blackburn, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Drawings, then consent
We draw the scheme, check it against the rules in England, and take it through the right consent with the council.
Structure and building control
A structural engineer sizes the foundations and steels, and we get building regulations approval before work starts.
On site
One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.

Questions about two-storey wraparound extensions in Blackburn

Who handles building regulations for a project in Blackburn?

We handle it as part of the project. What's needed in England: building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.

Which postcodes do you cover around Blackburn?

We cover Blackburn (BB1 and BB2) and nearby places including Darwen, Great Harwood and Accrington, plus the rest of Lancashire. The first site visit is free.

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

Our guide for North West England, which covers Blackburn, 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.

Is a wraparound extension better than separate side and rear extensions?

Building both at once usually costs less than two separate projects, because you pay for one set-up, one scaffold, one roof junction and one set of approvals. It also lets the layout be designed as a whole. The trade-off is a larger single outlay and a longer build, often 16 to 24 weeks at this size.

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.

Nearby

Close to Blackburn? We work across the area, including:

Other extensions in Blackburn

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

Ready to talk it through? Call us or send the form and we'll arrange a visit to your home in Blackburn.