House extensions in Kettering
Single and double storey extensions in Kettering, with the planning route and building control sorted first.
A single storey extension in Kettering typically costs £2,400–£3,200 per m² finished ready for decoration, roughly £29,000–£38,500 for a 12m² rear extension, with any kitchen fit-out priced separately. Building control in Kettering is North Northamptonshire Council building control: quoted by the council for each job.
- Typical cost
- £2,400–£3,200 per m²
- Building control
- Council building control: free quote per job
- Planning advice
- North Northamptonshire Council: £187
- Time on site
- Several weeks
Our 2026 guide prices, all in. Your fixed price comes in writing after the site visit. Council fees checked October 2026.
What house extensions in Kettering usually involve
Extending is the most cost-effective way to gain space and value without the upheaval of moving. We design and build single and double storey extensions, kitchen and dining extensions and rear and side returns across Kettering and the surrounding Northamptonshire villages — matched to the town's red-brick Victorian houses and its modern estates alike. Every build meets Building Regulations and is signed off through Local Authority Building Control, with the planning or permitted-development route confirmed before we start.
The extensions Kettering homes ask for most
Kettering's housing runs from Victorian terraces to modern estates, and the right extension depends on the age and style of the property.
Victorian and Edwardian terraces near the centre often suit a rear or side-return extension to open a narrow kitchen into a single bright family space. This typically means removing a load-bearing wall and installing a steel beam to a structural engineer's calculations, which we do as standard.
Red-brick and ironstone period homes need matched brick and sympathetic detailing, and where a conservation area applies we prepare the work to the standard a conservation officer expects.
Modern estate homes around Barton Seagrave and the edges of Kettering frequently allow rear extensions under permitted development, avoiding a full planning application. We confirm the route at the first visit.
What Building Regulations cover
Every extension must meet Building Regulations regardless of planning: foundations sized for the ground, a damp proof course tied into the existing wall, insulation to current standards, structural support over openings, fire safety, ventilation and drainage. We build to those standards and arrange Building Control inspections at foundations, damp proofing, structure and completion — so you receive the completion certificate a buyer's solicitor will later want.
Kettering & villages we cover
We cover Kettering and the surrounding villages including Barton Seagrave, Burton Latimer, Broughton, Geddington, Rothwell and Desborough.
Design & approvals
We help with drawings, structural calculations, the planning or permitted-development route and the Building Control application.
Build & structure
Foundations, matched brickwork, steel beams, roofing and weathering — inspected at each stage.
Thinking about extending in Kettering?
We will visit, talk through what's possible, check the planning position and quote in writing — all free and without pressure.
Ground, drainage and conservation in Kettering
Ground around Kettering ranges from ironstone to clay, and new-build plots are often compacted subsoil under a thin layer of topsoil. We check what is under each garden before choosing the base and the drainage.
Kettering has 26 conservation areas, including the town centre, Barton Seagrave, Burton Latimer, Geddington and Rothwell. Its Article 4 directions are site-specific, mostly older ones covering individual streets or buildings, so we check your address before designing anything that faces the road.
The River Ise runs along the east of the town, with river level stations at Barford Bridge and Slade Brook. You can check any address on the Environment Agency flood map.
Sources: North Northamptonshire Article 4 directions · Hanwood Park.
Permissions and fees in Kettering
- Planning routeMany single storey rear extensions are permitted development; a householder application costs £548 and a lawful development certificate £274 (national fees from April 2026). Planning Portal guidance
- Pre-application adviceIf anything is unclear, North Northamptonshire Council gives householder pre-application advice for £187. Pre-application advice
- Building regulationsNorth Northamptonshire Council building control: quoted by the council for each job. Building control fees
- Sewers and neighboursIf a public sewer runs within 3m, you need a build-over agreement with Anglian Water. Anglian Water: building over or near sewers
- BuildOne fixed written price, then the build, inspections and the completion certificate.
Council fees and rules checked October 2026. Planning fees are the national fees from 1 April 2026.
What you get
- Planning or permitted development route confirmed before anything starts
- Structural calculations and building regulations drawings arranged
- Stone or brick matched to the house
- Build-over agreements with Anglian Water where a sewer runs close
The specification
- Drawings, calculations and approvals
- Foundations inspected by building control
- Blockwork, insulation and the outer skin in matching stone or brick
- Roof, windows and doors
- First and second fix, plastering
- Completion certificate from building control
Rated 5.0 from 37 Google reviews
“Excellent Porch Extension by Lewis and the Team We recently had a porch extension completed by Lewis and his team, and we are extremely pleased with the result. From start to finish, Lewis was professional, reliable, and easy to communicate with. …”
Deepak · Porch extension — Google review
“These guys fitted our job in at short notice, did a great job despite the harsh weather. We had great communication throughout the project as it was not quite as simple as we first thought. We definitely recommend them and will be using them for future projects”
John — Google review
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House extensions in Kettering: questions
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Request a site visit in Kettering
We measure up, check levels and drainage, and send a written proposal with the build-up, the programme and one whole price. No pressure and no follow-up sales calls.