Blyth, Northumberland
Semi-detached rear extension in Blyth
Thinking about a semi-detached rear extension in Blyth? Single or two-storey extensions for semi-detached houses, with side access and one party wall. Our team handles the drawings, the planning route and the build, and your contract is with one company throughout.
Blyth sits in Northumberland, with postcode districts including NE23 and NE24. In Blyth we measure the attached neighbour's extension at the survey, because it often sets the sensible depth for yours.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a semi-detached rear extension cost in Blyth?
A semi-detached rear extension in Blyth is priced at £1,710–£2,790 per square metre including VAT as a guide, before kitchen fit-out and fees. North East prices are among the lowest in our range; former mining ground is the main foundation variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £20,500–£33,500 |
| 4 m wide × 5 m deep (20 m²) | £34,000–£56,000 |
| 4 m wide × 6 m deep (24 m²) | £41,000–£67,000 |
Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.
Do you need planning permission for a semi-detached rear extension in Blyth?
The planning route for a semi-detached rear extension in Blyth is set by England's householder rules and your council.
In England a single-storey rear extension can often be built under permitted development: up to 3 metres beyond the original rear wall of an attached house, or 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres if any part is within 2 metres of a boundary.
A two-storey rear extension can be permitted development in England only if it projects no more than 3 metres, stays at least 7 metres from the rear boundary, matches the existing roof pitch and has obscure-glazed upper side windows. In practice most double-storey rear extensions go through a householder planning application.
If 3 or 4 metres is not enough, England's prior approval route allows 6 metres on a terraced or semi-detached house and 8 metres on a detached house for a single-storey rear extension. Neighbours are consulted, the council decides within 42 days, and the fee is £249, rising to £310 from 8 December 2026.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Blyth like to extend?
Terraces and semis are typical around Blyth. On terraces a single-storey rear extension across the back yard is usually the practical choice; semis often have room for more.
How a semi-detached rear extension in Blyth comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Paperwork handled
Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
Fixed price and build
A written price for the agreed design, a start date and a named contact through the build, ending with the building control completion certificate.
Semi-detached rear extensions near Blyth
From Blyth, the nearest places we also cover are Bedlington (3.4 miles) and Ashington (4.1 miles).
- Semi-detached rear extension in Bedlington
- Semi-detached rear extension in Ashington
- Semi-detached rear extension in Cramlington
- Semi-detached rear extension in Whitley Bay
- Semi-detached rear extension in Morpeth
Other work in Blyth:
FAQ
Semi-detached rear extension questions in Blyth
What postcode areas do you cover around Blyth?
Including NE23 and NE24, and the surrounding Northumberland area.
Can you match the brick or stone on my Blyth house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
Can I match pebbledash or render?
Yes. Many semis are refinished with new render across the whole back elevation so old and new match.
How long does a rear extension take to build in Blyth?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
Is the site visit in Blyth free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.