First-floor extensions in Grange-over-Sands

Before you start in Grange-over-Sands, here's what applies.

Postcode districts: LA7 and LA11
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: Ulverston (7 miles), Morecambe (8.5 miles), Heysham (9.9 miles)
Distance to Carlisle: about 49.1 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.

Around Grange-over-Sands we also work in Ulverston, Morecambe and Heysham, and across the rest of Cumbria. Postcode districts in and near Grange-over-Sands: LA7 and LA11.

What it costs in Grange-over-Sands

In North West England, which includes Grange-over-Sands, we'd expect a first-floor extension to cost around £24,000–£34,500 for 4 m × 3.5 m of new first-floor space (14 m²), or £1,710–£2,470 per m² including VAT. Design fees, structural calculations and approval fees are separate and listed on our prices page.

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 Grange-over-Sands

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 Grange-over-Sands homes

Escape and fire safety

A new first-floor bedroom needs an escape window with a clear opening of at least 0.33 m², at least 450 mm wide and 450 mm high, with the bottom no more than 1,100 mm above the floor, unless there is a protected route to the stairs.

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

Look at the house
We start in Grange-over-Sands with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
Plans, then approval
Measured survey, design, then the right approval route for your house. We explain each step before we take it.
Technical design
We prepare the building regulations drawings, structural calculations and specification so the build price can be fixed.
On site
One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.

Questions about first-floor extensions in Grange-over-Sands

Which postcodes do you cover around Grange-over-Sands?

We cover Grange-over-Sands (LA7 and LA11) and nearby places including Ulverston, Morecambe and Heysham, plus the rest of Cumbria. The first site visit is free.

Do I need planning permission for a first-floor extension in Grange-over-Sands?

Grange-over-Sands is in England, so England planning rules apply. 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. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.

Who handles building regulations for a project in Grange-over-Sands?

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

Nearby towns we cover for first-floor extensions:

Other extensions in Grange-over-Sands

All two-storey extension services in Grange-over-Sands · First-floor extensions across Cumbria

Book a free site visit in Grange-over-Sands and we'll tell you what's possible, what approvals you need and what the design stage would cost.