First-floor extensions in Barrow-in-Furness

Quick reference for homeowners in Barrow-in-Furness.

Postcode districts: LA13 and LA14
County / area: Cumbria, England
Price region: North West England
Guide price: £24,000–£34,500 (£1,710–£2,470 per m²)
Approval route: It may be permitted development if it goes no more than 3 m beyond the original rear wall (counting any single-storey part) and stays 7 m from the rear boundary; otherwise it needs planning permission.
Nearest towns: Dalton-in-Furness (3.8 miles), Askam-in-Furness (5.3 miles), Millom (7.1 miles)
Distance to Carlisle: about 55.4 miles
First visit: Free, no obligation

About a first-floor extension

A first-floor extension is a new upstairs room built on top of an existing single-storey part of your house, such as a rear kitchen extension, a utility or a side annexe. It adds a bedroom, bathroom or study without enlarging the footprint. Whether it works depends mainly on whether the walls and foundations below can carry the extra load.

We cover postcode districts LA13 and LA14 in and around Barrow-in-Furness, along with neighbouring Dalton-in-Furness, Askam-in-Furness and Millom.

What it costs in Barrow-in-Furness

Expect a first-floor extension in Barrow-in-Furness to land somewhere around £24,000–£34,500 for 4 m × 3.5 m of new first-floor space (14 m²). Our North West England guide rate is £1,710–£2,470 per m², including VAT. Steelwork for wide openings is the item most likely to move the figure; we'll know once the engineer has designed it.

Spec	Per m²	4 m × 3.5 m of new first-floor space (14 m²)
Essential	£1,570–£2,270 per m²	£22,000–£32,000
Standard	£1,710–£2,470 per m²	£24,000–£34,500
Premium	£2,050–£2,960 per m²	£28,500–£41,500

Planning and building regulations in Barrow-in-Furness

In England, adding a first floor turns a single-storey extension into one of more than one storey. To be permitted development, the extension as a whole must go no more than 3 m beyond the rear wall of the original house and stay at least 7 m from the rear boundary, with matching materials and roof pitch. Over a side extension it always needs planning permission, costing £548 (or £575 for applications made from 8 December 2026).

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 Barrow-in-Furness homes

Replacing the flat roof

The existing roof usually comes off and is replaced by a new first-floor structure. The room below is exposed for a short time, so we plan temporary weatherproofing and sequence the work to keep the kitchen or living room usable for as long as possible.

Tying into the house

The new floor and walls must line up with the existing first floor, often through a new opening in the rear wall above the old one. Floor levels, the position of upstairs windows and the existing roof all affect where the opening can go, so we survey both floors carefully.

How we'd run your project

Understand the brief
At your home in Barrow-in-Furness we agree what you need: bedroom count, bathroom, kitchen space, and how much garden you want to keep.
Get it approved
Once you're happy with the design we submit it to the council for Barrow-in-Furness and deal with any questions from the planning officer.
Technical design
We prepare the building regulations drawings, structural calculations and specification so the build price can be fixed.
Build it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.

Questions about first-floor extensions in Barrow-in-Furness

Which postcodes do you cover around Barrow-in-Furness?

We cover Barrow-in-Furness (LA13 and LA14) and nearby places including Dalton-in-Furness, Askam-in-Furness and Millom, plus the rest of Cumbria. The first site visit is free.

How much does a first-floor extension cost in Barrow-in-Furness?

Our guide for North West England, which covers Barrow-in-Furness, is £1,710–£2,470 per m² including VAT. A typical project with 4 m × 3.5 m of new first-floor space (14 m²) comes to about £24,000–£34,500. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Who handles building regulations for a project in Barrow-in-Furness?

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.

What happens to the room below while the first floor is built?

The old roof is removed, so the room below is exposed for a short period. We fit temporary weather protection, plan the work so the roof comes off only when the new structure is ready, and agree with you which rooms will be out of use and for roughly how long.

Will the first-floor extension match my house?

It should, and in England matching materials and roof pitch is a condition of permitted development. We match brick, tile, mortar colour and window style where we can, and tell you at the design stage if an exact brick match is not available, so you can choose between the closest match and render or cladding.

Nearby

We also cover places near Barrow-in-Furness, including:

Other extensions in Barrow-in-Furness

All two-storey extension services in Barrow-in-Furness · First-floor extensions across Cumbria

The quickest next step is a visit. We'll look at your house in Barrow-in-Furness and give you an honest view of the options.