Planning permission for extensions in Northamptonshire
We prepare planning permission for extensions for homes across Northamptonshire, on their own or as the first stage of a full design and build project.
- Guide priceFrom £300 inc VAT
- PlanningWe find the right route for you
- Towns covered9
- Site visitFree, no obligation
Towns in Northamptonshire
What it costs in Northamptonshire
Fees below are our Northamptonshire guide (×0.95, the East Midlands factor), including VAT. Council and building control fees are extra.
| 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.
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. The East Midlands has plenty of inter-war and post-war semis and detached houses with room to extend, alongside Victorian terraces in the towns.
Do I need planning permission in Northamptonshire?
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.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
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).
Who this service is for
- Anyone unsure whether their extension needs permission
- Homeowners who would rather not deal with the council themselves
- Projects in conservation areas or with previous refusals
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
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
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
Who do I contract with in Northamptonshire?
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.
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.
Do you cover all of Northamptonshire?
Yes, across the whole of Northamptonshire. Site visits are free and there is no obligation.
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 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.