Planning permission for extensions in Northampton
For Northampton homeowners we handle planning permission for extensions, with fees agreed in writing before any work starts.
- Guide price in NorthamptonFrom £300 inc VAT
- PlanningWe find the right route for you
- Timescale8–13 weeks typical decision period
- Postcode districtsNN1, NN2, NN3, NN4, NN5
What is included
- Liaison with the planning officer
- Advice if conditions are attached or changes are requested
- Planning history and constraints check for your address
- Route recommendation in writing
A lawful development certificate is not compulsory for permitted development, but it is the cleanest proof that the extension was lawful when you come to sell. We usually recommend one.
Fees in Northampton
Guide fees for Northampton 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 | Permitted development confirmed in writing (certificate or notification) | £300 – £650 |
| Standard | Householder planning application handled | £550 – £1,050 |
| Premium | Application with heritage or design statements, and responses to the council | £850 – £1,550 |
Our handling fee only. Council fees are extra: in England from 1 April 2026 a householder application is £548, a lawful development certificate for a proposed extension £274 and a larger home extension prior approval £249. Drawings are priced separately.
Try the guide-price tool to see a range for your own size and finish.
Planning rules that apply in Northampton
In England the main routes are permitted development (ideally confirmed with a lawful development certificate, £274), larger home extension prior approval (£249, 42 days) and a householder planning application (£548, normally 8 weeks), with council fees as set from 1 April 2026.
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.
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.
Applications are decided by the local planning authority (your district, borough or unitary council).
Local to Northampton
We cover Northampton and the postcode districts NN1, NN2, NN3, NN4, NN5, NN7. Nearby, we also take on projects in Wellingborough (9 miles), Towcester (10 miles), Daventry (12 miles), Rushden (12 miles).
For homes towards Buckinghamshire, Milton Keynes is around 15 miles away. Homes across the East Midlands often have usable side land or a driveway beside the house, which opens up side and wraparound options.
From first visit to completion
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
We visit your Northampton home, measure up, talk through what you want and check the planning position.
Design and approvals
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Common questions in Northampton
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Northampton, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do you cover all of Northampton?
Yes. We cover Northampton and the surrounding parts of Northamptonshire. Site visits are free and there is no obligation.
Do I need building regulations approval in Northampton?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
How much does planning permission cost?
In England, from 1 April 2026 the council fee is £548 for a householder application, £274 for a lawful development certificate for a proposed extension and £249 for larger home extension prior approval. Our handling fee is separate.
What happens if planning is refused?
You can revise the design and reapply, or appeal. We read the officer’s report and tell you honestly which option has a better chance.
Book a free site visit in Northampton
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.