Corby · Northamptonshire

Kitchen extensions with bedrooms above in Corby

Want to stay in Corby but need more space? A kitchen extension with bedrooms above adds floor area on two levels without giving up much garden. Here's what's involved.

Before you start in Corby, here's what applies.

Postcode districts
NN17 and NN18
County / area
Northamptonshire, England
Price region
East Midlands
Guide price
£55,000–£74,000 (£1,960–£2,650 per m²), kitchen units and worktops priced separately
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
Uppingham (6.5 miles), Desborough (6.7 miles), Kettering (6.9 miles)
Distance to Northampton
about 18.9 miles
First visit
Free, no obligation

About a kitchen extension with bedrooms above

A kitchen extension with bedrooms above is a two-storey extension designed so the ground floor becomes a larger, usually open-plan kitchen and dining space, with one or two bedrooms or a bathroom on the first floor. It is a natural fit for a two-storey rear extension. The key design issues are the steel beams that open up the house, glazing and ventilation.

Around Corby we also work in Uppingham, Desborough and Kettering, and across the rest of Northamptonshire. Postcode districts in and near Corby: NN17 and NN18.

What it costs in Corby

In the East Midlands, which includes Corby, we'd expect a kitchen extension with bedrooms above to cost around £55,000–£74,000 (kitchen units and worktops priced separately) 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. The fastest way to a firmer number is a free site visit, after which we price the design stage in writing.

SpecPer m²A 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 Corby

In England, a two-storey rear kitchen extension can be permitted development if it goes no more than 3 m beyond the rear wall of the original house and stays at least 7 m from the rear boundary, with matching materials and roof pitch, outside protected areas. No balconies are allowed. Deeper designs need 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 Corby homes

Steel beams and the open-plan opening

Removing the old rear wall to make one large room means a steel beam, sometimes several, to carry the first floor and roof. The engineer sizes the steel and its supports, and we decide early whether you want a flush ceiling with the beam hidden or a downstand, as this affects ceiling heights.

Glazing and the Part L 25% rule

In England, new windows, roof lights and glazed doors in an extension are normally limited to 25% of the extension's floor area plus the area of any windows or doors removed. Larger glazing is possible, but needs SAP or compensating calculations, so we plan the rear doors around this from the start.

How we'd run your project

  1. Look at the house

    We start in Corby with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.

  2. Drawings, then consent

    We draw the scheme, check it against the rules in England, and take it through the right consent with the council.

  3. Engineer it

    Foundations sized for two floors, steels for any openings, and building control approval, all before anyone starts on site.

  4. On site

    One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.

Questions about kitchen extensions with bedrooms above in Corby

How long does a kitchen extension with bedrooms above 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.

How much does a kitchen extension with bedrooms above cost in Corby?

Our guide for the East Midlands, which covers Corby, 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 (kitchen units and worktops priced separately). 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 Corby?

We cover Corby (NN17 and NN18) and nearby places including Uppingham, Desborough and Kettering, plus the rest of Northamptonshire. The first site visit is free.

Is it cheaper to build a kitchen extension and bedrooms at the same time?

Yes, in most cases. Building both floors at once means one set of foundations, one roof, one scaffold and one set of approvals. Adding a first floor later means removing the original roof, possibly strengthening the foundations and disrupting the kitchen again. If you think you will need the bedroom, build it now.

Can I keep using my kitchen during the build?

For part of it. The new structure can be built while your existing kitchen stays in use, but when the rear wall is opened and the new kitchen is fitted there will be several weeks without one. We plan when this happens and help you set up a temporary kitchen elsewhere in the house.

Nearby

We also cover places near Corby, including:

Other extensions in Corby

All two-storey extension services in Corby · Kitchen extensions with bedrooms above across Northamptonshire

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

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