Home office extensions for homes in Northamptonshire
Planning a home office extension in Northamptonshire? We survey the house, work out the planning route, draw the design and build it, so you deal with one team from the first visit to the completion certificate.
- Guide priceFrom £15,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Towns covered9
- Site visitFree, no obligation

Towns in Northamptonshire
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.
What should I budget for a home office extension in Northamptonshire?
Labour and material costs vary across the UK, so for Northamptonshire we use our East Midlands factor (×0.95). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Northamptonshire: £1,760 to £3,230 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 3.2 m 8 m² | £15,000 – £18,500 | £16,000 – £21,000 | £20,500 – £26,000 |
| 3 m × 3.6 m 11 m² | £19,000 – £23,000 | £22,000 – £28,500 | £28,000 – £36,000 |
| 3 m × 5 m 15 m² | £26,000 – £31,500 | £30,500 – £38,500 | £38,000 – £48,500 |
Try the guide-price tool to see a range for your own size and finish.
Do I need planning permission in Northamptonshire?
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
The planning position for a specific Northamptonshire address depends on its history and any designations, which is why we check it at the first visit.
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).
Included in a typical project
- Window and rooflight placement to avoid screen glare
- Layout for desk, storage and video calls
- Data cabling and plenty of sockets
- Sound insulation to the adjoining rooms
- Heating or cooling sized for the room
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
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
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
Do you cover all of Northamptonshire?
Yes, across the whole of Northamptonshire. Site visits are free and there is no obligation.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Northamptonshire, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
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.
How much does a home office extension cost?
Our guide range is about £1,760 to £3,230 per m² including VAT. An 11 m² standard-spec office is typically £22,000 to £28,500 in Northamptonshire.
Can I claim the cost against tax?
Building work on your home is not normally an allowable business expense, and claiming it can have capital gains tax effects. Speak to an accountant before assuming any tax relief.
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.