A double-storey extension adds two floors of new space to your house in one build, typically a larger kitchen or living room downstairs with an extra bedroom, bathroom or en-suite above, sharing one set of foundations and one roof.
For a homeowner in Blyth, planning a double-storey extension tends to begin with two questions: what will it cost, and how disruptive will it be? Our guide range is £54,000–£108,000 including VAT, and a typical job runs to 14–22 weeks on site. Both numbers firm up once we have seen the property, measured up and agreed exactly what is included.
- Guide price
- £54,000–£108,000 inc VAT
- Time on site
- 14–22 weeks on site
- Postcodes
- NE23 and NE24
- Planning rules
- England
- Local area
- Northumberland
- Survey
- Free, with a written quote
What should you budget for a double-storey extension in Blyth?
Here is how the guide price for a double-storey extension breaks down in Blyth. We start from national figures and adjust for the North East, which comes out about 10% below the national guide. The resulting range, VAT included, is £54,000–£108,000, and a survey, at no cost to you, firms it up.
| Type of job | What it usually involves | Guide in Blyth |
|---|---|---|
| Small (15–20m² total) | A compact rear or side extension adding a small room on each floor. | £36,000–£58,000 |
| Typical (30–40m² total) | A larger kitchen or living room below with a double bedroom or en-suite above. | £54,000–£108,000 |
| Large (50m² plus total) | Wide or deep extensions, often with a new bathroom, steelwork and high-spec glazing. | £90,000–£162,000 |
Expect these to shape the final quote:
- Combined floor area across both storeys
- Bathrooms, en-suites and plumbing on the upper floor
- Foundation depth, ground conditions and drains to divert
- Scaffolding duration, access and the level of finishes
What do you get?
- Insulated cavity walls with brick or render to match the house
- First-floor joists, stud walls and new openings upstairs
- Roof structure tied into the existing roof, tiled to match
- Scaffolding for the full build, erected and inspected
- Windows, external doors, plastering and internal doors
- Building control inspections and completion certificate
What are homes like around Blyth?
Stone dominates rural Northumberland, from sandstone farmhouses and villages to fortified bastle houses in the uplands. Alnwick, Hexham and Morpeth have historic stone centres, Berwick has Georgian streets, and south-east towns such as Ashington, Blyth and Bedlington have colliery terraces. Cramlington grew from the 1960s with planned estates.
Stone homes often need lime pointing, roof slating and breathable render. Colliery terraces suit loft conversions and rear extensions, and estate homes commonly take garage conversions and window upgrades.
None of this holds for every street in Blyth, which is why we look at your actual house before pricing a double-storey extension rather than assuming from its age alone.
Planning and building rules in Blyth
Because Blyth falls under England's rules, the guidance below is the version relevant to you. Before sending a price, we check your property's position with the council.
In England, a two-storey rear extension can only be permitted development if it is no more than 3 m deep, at least 7 m from the rear boundary and finished to match the house. Most double-storey and all two-storey side extensions need full planning permission.
Building Regulations approval is needed, with structural calculations for beams, foundations and the roof. The Party Wall etc. Act 1996 often applies on semi-detached and terraced houses.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
How does the job run?
A visit to your home
We begin by looking at the job in person. During the free survey we discuss options, materials and budget for a double-storey extension, and photograph or measure anything the quote needs to reflect.
Quote in writing
We turn the survey notes into a written quote. The price is fixed for the specification we agree, and the document sets out materials, scope and payment stages in plain language.
Booking the work
Preparation matters as much as the build. We agree access, parking and working hours with you, order materials in good time, and confirm any permissions so the job isn't held up once it starts.
Build and hand over
Our trades complete a double-storey extension while your point of contact keeps you updated. When everything is finished, we clear the site, take away waste and go through the result with you before handover.
Working with SK Home Improvements
Questions about a double-storey extension in Blyth
How is the new roof joined to the existing house?
The new roof is usually tied into the existing roof so the two read as one. On a rear extension this often means a lower ridge or a hipped end, with valleys where the slopes meet. We strip back some existing tiles, fix new rafters and battens, and lay matching tiles or slates. Lead or proprietary flashings seal the junctions so water runs off properly.
Who do I deal with during the job?
One point of contact manages your project from survey to handover. They schedule the trades working under our contract, keep you updated on progress, and are the person to call with any question. You don't need to coordinate builders, electricians or decorators separately, because that is part of what we do.
How much will a double-storey extension cost in Blyth?
As a guide, expect to pay £54,000–£108,000 including VAT for a double-storey extension in Blyth. That range is adjusted for the North East, which runs about 10% below the national guide. Where your project lands depends on size, materials, access and the condition of what is already there. We confirm a fixed price in writing after a free survey of your home.
Do I need planning permission for a two-storey extension?
Most two-storey extensions need planning permission, but it depends on the size, height and position, your home's location, whether it is listed or in a conservation area, and which UK nation you are in. In England, a two-storey rear extension can sometimes be built under permitted development if it is no deeper than 3m and at least 7m from the rear boundary. We check what applies before quoting.
How much does a double-storey extension cost?
A typical double-storey extension of 30–40m² across both floors costs £54,000–£108,000, built to a plastered finish. As a rough guide, allow around £1,400–£2,600 per square metre plus fixed costs for groundworks, scaffolding and fees. The second storey usually costs less per square metre than the first, because foundations and roof are shared. Bathrooms upstairs and a complex roof add most. We confirm a fixed price after the survey.
Near Blyth
Whether you're in the centre of Blyth or on its outskirts, NE23 and NE24 addresses are covered. We extend the same service, and the same fixed-price approach, to Bedlington, Ashington and Cramlington.