Double-storey extensions for homes in Northallerton
Our design and build teams take on double-storey extensions in Northallerton, from the first measured survey through planning and building control to the finished room.
- Guide price in NorthallertonFrom £35,500 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsDL7
How much does a double-storey extension cost in Northallerton?
Prices below are for Northallerton, using the Yorkshire and the Humber factor of ×0.94. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Northallerton: £1,460 to £2,820 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m, two floors 24 m² | £35,500 – £43,000 | £40,500 – £53,500 | £51,500 – £68,000 |
| 4 m × 4 m, two floors 32 m² | £46,500 – £56,000 | £54,000 – £71,000 | £69,000 – £90,500 |
| 4 m × 6 m, two floors 48 m² | £69,500 – £83,500 | £81,000 – £106,500 | £103,500 – £135,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
When a double-storey extension makes sense
- Growing families who need a bedroom as well as a bigger kitchen
- Homeowners who would otherwise consider moving
- Houses with enough distance to the rear or side boundary
Planning and approvals in Northallerton
In England a two-storey rear extension is permitted development only if it projects no more than 3 m from the original rear wall, sits at least 7 m from the rear boundary, matches the roof pitch and uses obscure, non-opening side windows upstairs. Most two-storey extensions therefore go through a householder planning application, which costs £548 from 1 April 2026 and normally takes about 8 weeks.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
Extensions in and around Northallerton
Our survey diary covers Northallerton, including DL7. Neighbouring towns we cover include Ripon (13 miles), Middlesbrough (19 miles), Harrogate (24 miles), Redcar (26 miles).
Yorkshire and the Humber combines stone-built terraces in the Pennine towns with brick semis and newer estates elsewhere, so materials and roof details need matching with care.
Our process, step by step
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Questions people ask about double-storey extensions
How long does a double-storey extension take to build in Northallerton?
On site, typically 16 to 24 weeks once approvals are in place. Before that, allow 8–16 weeks design and approvals.
Who do I contract with for a double-storey extension in Northallerton?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Do you cover all of Northallerton?
Yes. We cover Northallerton and the surrounding parts of North Yorkshire. Site visits are free and there is no obligation.
Does a double-storey extension need planning permission?
Often, yes. In England a two-storey rear extension can be permitted development only if it projects no more than 3 m and sits at least 7 m from the rear boundary, with matching roof pitch and obscure side windows. Side extensions over one storey always need planning permission. We confirm the route at the survey.
Is a two-storey extension cheaper per square metre?
Usually. Our guide range is about £1,460 to £2,820 per m² of new floor area including VAT, compared with £1,640 to £3,200 per m² for single-storey work, because the foundations and roof are shared across two floors.
Book a free site visit in Northallerton
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.