Annexe extensions in Corby: design, approvals and build
Our design and build teams take on annexe extensions in Corby, from the first measured survey through planning and building control to the finished room.
- Guide price in CorbyFrom £52,000 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsNN17, NN18
Covering Corby
We cover Corby and the postcode districts NN17, NN18. The same team covers Kettering (7 miles), Market Harborough (10 miles), Wellingborough (13 miles), Rushden (15 miles), all within easy reach.
For homes towards Rutland, Oakham is around 11 miles away. 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.
How much does an annexe extension cost in Corby?
Labour and material costs vary across the UK, so for Corby we use our East Midlands factor (×0.95). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Corby: £1,900 to £3,610 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Studio annexe 25 m² | £52,000 – £65,500 | £57,000 – £71,500 | £71,000 – £90,500 |
| One-bedroom annexe 35 m² | £66,500 – £83,500 | £79,500 – £100,000 | £99,500 – £126,500 |
| Larger annexe 45 m² | £85,500 – £107,000 | £102,500 – £128,500 | £128,000 – £162,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
Planning and approvals in Corby
In England an annexe that stays part of the household and connects to the house is assessed as an extension, but its size usually takes it beyond permitted development, so a householder application describing the ancillary use is the normal route.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
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).
What we take care of
- Kitchenette, shower room and bedroom finish
- Fire separation and alarms to building regulations
- Planning application describing ancillary use
- Design for accessibility: level thresholds, wider doors, walk-in shower
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 Corby home, measure up, talk through what you want and check the planning position.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
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
The build is managed from start to finish, inspected at each stage and signed off on completion.
Your questions about an annexe extension in Corby
How long does an annexe extension take to build in Corby?
On site, typically 16 to 24 weeks once approvals are in place. Before that, allow 10–16 weeks design and approvals.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Corby, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Who do I contract with for an annexe extension in Corby?
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.
Can the annexe have its own front door?
Yes, many do, but it should still connect to the main house to stay clearly part of it.
Will an annexe affect council tax?
It can. Some annexes are assessed separately for council tax, with discounts or exemptions in some cases when occupied by a relative. Check with the Valuation Office Agency (England and Wales), your local assessor (Scotland) or Land & Property Services (Northern Ireland).
Book a free site visit in Corby
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.