First-floor extensions in Newbiggin-by-the-Sea

Quick reference for homeowners in Newbiggin-by-the-Sea.

Postcode districts: NE64
County / area: Northumberland, England
Price region: North East England
Guide price: £22,500–£33,000 (£1,620–£2,340 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: Ashington (2 miles), Stakeford (2.9 miles), Blyth (4 miles)
Distance to Blyth: about 4 miles
First visit: Free, no obligation

About a first-floor extension

A first-floor extension suits you if your house already has a single-storey extension and you need more space upstairs. You get a structural check of the existing walls and foundations, a design that ties the new floor into the house, the approvals your nation needs, building regulations approval and the build, managed by us and carried out by vetted teams working under S&K.

We cover Newbiggin-by-the-Sea (NE64) and the places around it, including Ashington (2.0 miles), Stakeford (2.9 miles) and Blyth.

What it costs in Newbiggin-by-the-Sea

For budgeting in Newbiggin-by-the-Sea, allow around £22,500–£33,000 for a first-floor extension with 4 m × 3.5 m of new first-floor space (14 m²). That's based on £1,620–£2,340 per m² including VAT for North East England. These are guides, not quotes. Ground conditions, steelwork and access can move the figure either way.

Spec	Per m²	4 m × 3.5 m of new first-floor space (14 m²)
Essential	£1,490–£2,150 per m²	£21,000–£30,000
Standard	£1,620–£2,340 per m²	£22,500–£33,000
Premium	£1,940–£2,810 per m²	£27,000–£39,500

Planning and building regulations in Newbiggin-by-the-Sea

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 Newbiggin-by-the-Sea 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

Measure and listen
A visit to Newbiggin-by-the-Sea to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Drawings, then consent
We draw the scheme, check it against the rules in England, and take it through the right consent with the council.
Fixed price in writing
With approved drawings and calculations, we give you a fixed build price and a programme you can plan around.
Build and sign-off
Vetted teams working under S&K build the extension, and we arrange the building control completion certificate at the end.

Questions about first-floor extensions in Newbiggin-by-the-Sea

Which postcodes do you cover around Newbiggin-by-the-Sea?

We cover Newbiggin-by-the-Sea (NE64) and nearby places including Ashington, Stakeford and Blyth, plus the rest of Northumberland. The first site visit is free.

Do I need planning permission for a first-floor extension in Newbiggin-by-the-Sea?

Newbiggin-by-the-Sea 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.

How long does a first-floor 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.

Can I build on top of my existing single-storey extension?

Often yes, but only after the structure has been checked. Foundations, walls and lintels built for one storey may not carry two. We dig trial holes, look for the original building control approval and ask the structural engineer to confirm what can stay, what needs strengthening and what must be rebuilt.

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.

Nearby

The same service in neighbouring towns:

Other extensions in Newbiggin-by-the-Sea

All two-storey extension services in Newbiggin-by-the-Sea · First-floor extensions across Northumberland

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