Two-storey side extensions in Blyth
A two-storey side extension is one of the most space-efficient ways to add bedrooms and living space to a house in Blyth, because the new floors share one set of foundations and one roof.
Before you start in Blyth, here's what applies.
- Postcode districts
- NE24
- County / area
- Northumberland, England
- Price region
- North East England
- Guide price
- £77,500–£104,000 (£1,840–£2,480 per m²)
- Approval route
- Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
- Nearest towns
- Cowpen (1.3 miles), Bedlington (3.4 miles), Stakeford (3.5 miles)
- First visit
- Free, no obligation
About a two-storey side extension
A two-storey side extension is a new two-floor addition built into the space beside your house, often over a driveway or side passage. It typically adds one or two bedrooms upstairs and a utility, study or larger kitchen below, without giving up rear garden.
We cover postcode district NE24 in and around Blyth, along with neighbouring Cowpen, Bedlington and Stakeford.
What it costs in Blyth
For budgeting in Blyth, allow around £77,500–£104,000 for a two-storey side extension with a 3 m × 7 m footprint on two floors (42 m² of new floor space). That's based on £1,840–£2,480 per m² including VAT for North East England. Design fees, structural calculations and approval fees are separate and listed on our prices page.
| Spec | Per m² | A 3 m × 7 m footprint on two floors (42 m² of new floor space) |
|---|---|---|
| Essential | £1,700–£2,280 per m² | £71,500–£95,500 |
| Standard | £1,840–£2,480 per m² | £77,500–£104,000 |
| Premium | £2,210–£2,970 per m² | £93,000–£124,500 |
Planning and building regulations in Blyth
In England, a two-storey side extension always needs householder planning permission, because permitted development only allows single-storey extensions beyond a side wall. The fee is £548 (or £575 for applications made from 8 December 2026), and councils should decide within 8 weeks of validation. Expect them to look at set-back, roof height, gaps to the boundary and the effect on neighbours.
Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.
Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.
Design points for Blyth homes
Set-down and set-back
Councils usually want a two-storey side extension to look subordinate to the house. Setting the front wall back from the main front and dropping the ridge slightly below the main roof helps it read as an addition, and is often expected in local design guidance.
Access and services
Side extensions often cover the only route to the back garden, a gas meter, soil pipes or a drain run. We plan bin and bike access, move meters and pipes where needed and check drains early, because these items affect both cost and layout.
How we'd run your project
Measure and listen
A visit to Blyth to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in England before drawing in detail.
Detail and price
Construction drawings, engineer's calculations and building control sign-off, then a written fixed price for the build.
Finish and certify
Second fix, plastering and making good, then building control's final inspection and the completion paperwork.
Questions about two-storey side extensions in Blyth
How much does a two-storey side extension cost in Blyth?
Our guide for North East England, which covers Blyth, is £1,840–£2,480 per m² including VAT. A typical project with a 3 m × 7 m footprint on two floors (42 m² of new floor space) comes to about £77,500–£104,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.
How long does a two-storey side extension take?
Allow 4 to 8 weeks for survey and design, then the approval period (councils should decide householder applications within 8 weeks of validation), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.
Which postcodes do you cover around Blyth?
We cover Blyth (NE24) and nearby places including Cowpen, Bedlington and Stakeford, plus the rest of Northumberland. The first site visit is free.
Do I need planning permission for a two-storey side extension in Blyth?
Blyth is in England, so England planning rules apply. Planning permission is needed: in England, permitted development only allows single-storey extensions to the side. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.
Can I build a two-storey side extension over my driveway?
Yes, if the drive is wide enough for a useful room and the council accepts the design. You may lose off-road parking, which some councils weigh up, and the foundations need to suit the ground below. We check parking, drains and meter positions at the free site visit before any drawings are prepared.
Nearby
Close to Blyth? We work across the area, including:
Other extensions in Blyth
- Rear
- Wraparound
- Part two-storey
- Over a garage
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Blyth · Two-storey side extensions across Northumberland
The quickest next step is a visit. We'll look at your house in Blyth and give you an honest view of the options.