Two-storey wraparound extensions in Northampton

Useful details for planning a two-storey wraparound extension in Northampton.

Postcode districts: NN1, NN2, NN3, NN4, NN5, NN6 and nearby districts
County / area: Northamptonshire, England
Price region: East Midlands
Guide price: £118,000–£162,000 (£2,110–£2,890 per m²)
Approval route: Planning permission is needed: the side part takes it outside permitted development in England.
Nearest towns: Wellingborough (8.8 miles), Daventry (11.7 miles), Rushden (12.2 miles)
First visit: Free, no obligation

About a two-storey wraparound extension

A two-storey wraparound extension is an L-shaped addition that extends both the side and the rear of your house, on two floors. It gives one of the largest gains in floor space of any extension, typically a big open-plan kitchen and living area below and two or more bedrooms or bathrooms above. In England it needs planning permission, because the side part is more than one storey.

We cover Northampton (NN1, NN2, NN3, NN4, NN5, NN6 and nearby districts) and the places around it, including Wellingborough (8.8 miles), Daventry (11.7 miles) and Rushden.

What it costs in Northampton

Most of the cost of a two-storey wraparound extension is set by its size and specification. For Northampton and the rest of the East Midlands, our guide is £2,110–£2,890 per m² including VAT, so about £118,000–£162,000 for an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space). The fastest way to a firmer number is a free site visit, after which we price the design stage in writing.

Spec	Per m²	An L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space)
Essential	£1,940–£2,660 per m²	£108,500–£149,000
Standard	£2,110–£2,890 per m²	£118,000–£162,000
Premium	£2,530–£3,470 per m²	£141,500–£194,500

Planning and building regulations in Northampton

In England, a two-storey wraparound extension needs householder planning permission, because any extension beyond a side wall must be single storey to be permitted development. The application costs £548 (or £575 for applications made from 8 December 2026). Councils weigh the side part against the street scene and the rear part against neighbours' light and outlook, and should decide within 8 weeks of validation.

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 Northampton homes

Phasing the build

A wraparound touches two sides of the house at once, so the kitchen and often the rear rooms are out of use for part of the build. We plan the sequence so you keep a working kitchen and bathroom for as long as possible, or advise when moving out briefly makes sense.

Two roofs that meet

A wraparound needs the side roof and rear roof to join cleanly, often with a valley or hip where they meet. Getting pitches and ridge heights right keeps rainwater moving and avoids a bulky mass at the back corner, which neighbours and planners notice.

How we'd run your project

Look at the house
We start in Northampton with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
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 it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.

Questions about two-storey wraparound extensions in Northampton

Which postcodes do you cover around Northampton?

We cover Northampton (NN1, NN2, NN3, NN4, NN5, NN6 and nearby districts) and nearby places including Wellingborough, Daventry and Rushden, plus the rest of Northamptonshire. The first site visit is free.

Who handles building regulations for a project in Northampton?

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.

How long does a two-storey wraparound 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.

Does a wraparound extension need steel?

Almost always. Opening the corner of the house and the old rear wall to make one open-plan space means steel beams, and often a steel post or frame at the outside corner. The structural engineer sizes these, and the steel is ordered once the design is fixed, which is one reason a wraparound needs careful sequencing.

Can a wraparound extension be part single, part two-storey?

Yes. Many wraparounds keep the rear part single storey with roof lights over the kitchen and put the two-storey part to the side. This can reduce the effect on neighbours and the cost. We set out both options at the design stage, so you can compare floor space against price before choosing.

Nearby

The same service in neighbouring towns:

Other extensions in Northampton

All two-storey extension services in Northampton · Two-storey wraparound extensions across Northamptonshire

Tell us about your house in Northampton and we'll call you back to arrange a free, no-obligation visit.