Two-storey rear extensions in Brackley

Brackley: the key facts for this kind of project.

Postcode districts: NN13
County / area: Northamptonshire, England
Price region: East Midlands
Guide price: £55,000–£74,000 (£1,960–£2,650 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: Buckingham (7.3 miles), Banbury (8.4 miles), Bicester (9.2 miles)
Distance to Northampton: about 18.8 miles
First visit: Free, no obligation

About a two-storey rear extension

A two-storey rear extension suits you if you need more room on both floors and have a reasonably deep garden. You get one team for the whole job: a measured survey, the design, a check on whether permitted development applies, planning drawings where they are needed, structural design, building regulations approval and the build itself, carried out by vetted teams working under S&K. Every project starts with a free site visit.

Around Brackley we also work in Buckingham, Banbury and Bicester, and across the rest of Northamptonshire. Postcode district in and near Brackley: NN13.

What it costs in Brackley

In the East Midlands, which includes Brackley, we'd expect a two-storey rear extension to cost around £55,000–£74,000 for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space), or £1,960–£2,650 per m² including VAT. Design fees, structural calculations and approval fees are separate and listed on our prices page.

Spec	Per m²	A 4 m × 3.5 m footprint on two floors (28 m² of new floor space)
Essential	£1,800–£2,430 per m²	£50,500–£68,000
Standard	£1,960–£2,650 per m²	£55,000–£74,000
Premium	£2,350–£3,180 per m²	£66,000–£89,000

Planning and building regulations in Brackley

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 Brackley homes

Roof form

A hipped or gabled roof that matches the pitch of the main house usually looks best, and matching the pitch is a permitted development condition in England. Keeping the ridge below the main ridge makes the extension read as secondary and avoids awkward junctions with existing gutters and windows.

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

Understand the brief
At your home in Brackley we agree what you need: bedroom count, bathroom, kitchen space, and how much garden you want to keep.
Drawings, then consent
We draw the scheme, check it against the rules in England, and take it through the right consent with the council.
Technical design
We prepare the building regulations drawings, structural calculations and specification so the build price can be fixed.
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 Brackley

How much does a two-storey rear extension cost in Brackley?

Our guide for the East Midlands, which covers Brackley, is £1,960–£2,650 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 £55,000–£74,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

Which postcodes do you cover around Brackley?

We cover Brackley (NN13) and nearby places including Buckingham, Banbury and Bicester, plus the rest of Northamptonshire. The first site visit is free.

Who handles building regulations for a project in Brackley?

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.

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 Brackley? We work across the area, including:

Other extensions in Brackley

All two-storey extension services in Brackley · Two-storey rear extensions across Northamptonshire

Want a figure first? Try our guide price tool, then book a free visit to firm it up.