Two-storey rear extensions in Newbiggin-by-the-Sea

What we'd confirm first for a project in Newbiggin-by-the-Sea.

Postcode districts: NE64
County / area: Northumberland, England
Price region: North East England
Guide price: £50,500–£68,000 (£1,800–£2,430 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 two-storey rear extension

A two-storey rear extension is a new two-floor addition built onto the back of your house, usually giving a larger kitchen or living space on the ground floor and one or two bedrooms or a bathroom above. Because both floors share one set of foundations and one roof, it adds a lot of floor space for the garden it uses. In some cases it can be built under permitted development, depending on where you live.

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

In North East England, which includes Newbiggin-by-the-Sea, we'd expect a two-storey rear extension to cost around £50,500–£68,000 for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space), or £1,800–£2,430 per m² including VAT. We'll give you a written design-stage price first, then a fixed build price once the drawings are agreed.

Spec	Per m²	A 4 m × 3.5 m footprint on two floors (28 m² of new floor space)
Essential	£1,660–£2,240 per m²	£46,500–£62,500
Standard	£1,800–£2,430 per m²	£50,500–£68,000
Premium	£2,160–£2,920 per m²	£60,500–£81,500

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

In England, a two-storey rear extension can be permitted development if it goes no more than 3 m beyond the rear wall of the original house, stays at least 7 m from the rear boundary and matches the house's materials and roof pitch. It is not permitted development in conservation areas, National Landscapes, National Parks, World Heritage Sites or the Broads. Otherwise a householder application costs £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

Opening up the ground floor

Knocking through the old rear wall means steel beams to carry the first floor and roof above. The structural engineer sets the beam sizes, padstones and any posts, and we plan them early so the open-plan layout you want is the one that gets built.

Foundations and drains

Foundations for two storeys carry more load than a single storey and may need to go deeper near trees or on clay. Rear extensions often sit near drains, so we check sewer records early, as building over or near a public sewer may need the water company's agreement.

How we'd run your project

Free site visit
We visit your home in Newbiggin-by-the-Sea, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Design and approvals
We draw the extension and check it against the rules for England, then apply for planning permission or a certificate of lawfulness, whichever fits.
Engineer it
Foundations sized for two floors, steels for any openings, and building control approval, all before anyone starts on site.
Build and hand over
We manage the build from groundworks to decoration-ready finish and hand over with the completion paperwork.

Questions about two-storey rear extensions in Newbiggin-by-the-Sea

How long does a two-storey rear 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.

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.

How much does a two-storey rear extension cost in Newbiggin-by-the-Sea?

Our guide for North East England, which covers Newbiggin-by-the-Sea, is £1,800–£2,430 per m² including VAT. A typical project with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) comes to about £50,500–£68,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Will a two-storey rear extension block my neighbour's light?

It can if it is too deep or too close to the boundary, which is why councils look closely at its effect on neighbouring windows and gardens. We test the design against light and outlook early, keep the first floor shorter or set in where needed, and use a hipped roof to reduce bulk on the boundary side.

Can I have a balcony on a two-storey rear extension?

In England, balconies, verandas and raised platforms are not permitted development, so a balcony on a two-storey rear extension needs planning permission. A Juliet balcony, a guard rail across full-height doors with no platform to stand on, is often a practical alternative, but it still needs checking against the rules and the council's approach to overlooking.

Nearby

Close to Newbiggin-by-the-Sea? We work across the area, including:

Other extensions in Newbiggin-by-the-Sea

All two-storey extension services in Newbiggin-by-the-Sea · Two-storey rear extensions across Northumberland

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