Building regulations for extensions across Northamptonshire
We prepare building regulations for extensions for homes across Northamptonshire, on their own or as the first stage of a full design and build project.
- Guide priceFrom £850 inc VAT
- Approval routeFull plans or building notice
- Towns covered9
- Site visitFree, no obligation
Towns in Northamptonshire
Design and approval fees for Northamptonshire
Guide fees for Northamptonshire including VAT, using our East Midlands factor of ×0.95. Council and building control charges are not included.
| Option | What it covers | Guide price |
|---|---|---|
| Essential | Building regulations drawings for a simple single-storey extension | £850 – £1,750 |
| Standard | Drawings plus structural calculations | £1,200 – £2,500 |
| Premium | Complex or two-storey pack with energy calculations | £2,050 – £3,650 |
Our design fee only. Building control charges are set by your council (or, in England and Wales, a registered building control approver) and quoted separately.
For a figure based on your own dimensions, use our guide-price tool.
Local to Northamptonshire
Towns we cover in Northamptonshire include Northampton, Corby, Kettering, Wellingborough, Rushden, Daventry, Market Harborough, Towcester. Homes across the East Midlands often have usable side land or a driveway beside the house, which opens up side and wraparound options.
Will the council need to approve it?
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.
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 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).
Included in a typical project
- Inspection bookings throughout the build
- Building regulations drawings and written specification
- Structural calculations for beams, lintels and foundations
- Energy and glazing checks, including whole-house calculations if needed
- Completion certificate on sign-off
- Submission to the council or a registered building control approver
How the project works
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
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
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
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Common questions in Northamptonshire
Do you cover all of Northamptonshire?
Yes, across the whole of Northamptonshire. Site visits are free and there is no obligation.
Do I need building regulations approval in Northamptonshire?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Will my neighbours in Northamptonshire be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
What are the insulation standards for an extension?
In England, new walls in an extension should achieve a U-value of 0.18 W/m²K, roofs 0.15 and floors 0.18, with windows at 1.4 and rooflights at 2.2. Wales, Scotland and Northern Ireland set their own figures.
Who are building control?
Either your local council’s building control team or a registered building control approver. Both inspect the work and issue the completion certificate.
Book a free site visit in Northamptonshire
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.