Extensions over a garage in Blyth

Before you start in Blyth, here's what applies.

Postcode districts: NE24
County / area: Northumberland, England
Price region: North East England
Guide price: £28,500–£41,500 (£1,580–£2,300 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 an extension over a garage

An extension over a garage is a new first-floor room built on top of an existing attached garage, usually a bedroom, en-suite or study. It uses a footprint you already have, so it adds floor space without taking any garden. The garage walls and foundations often need strengthening or replacing to carry the new floor.

We cover Blyth (NE24) and the places around it, including Cowpen (1.3 miles), Bedlington (3.4 miles) and Stakeford.

What it costs in Blyth

Most of the cost of an extension over a garage is set by its size and specification. For Blyth and the rest of North East England, our guide is £1,580–£2,300 per m² including VAT, so about £28,500–£41,500 for 3 m × 6 m of new first-floor space (18 m²). Design fees, structural calculations and approval fees are separate and listed on our prices page.

Spec	Per m²	3 m × 6 m of new first-floor space (18 m²)
Essential	£1,450–£2,110 per m²	£26,000–£38,000
Standard	£1,580–£2,300 per m²	£28,500–£41,500
Premium	£1,890–£2,750 per m²	£34,000–£49,500

Planning and building regulations in Blyth

In England, most garages sit beside the house, so building over one makes a two-storey extension beyond a side wall, which always needs planning permission. If the garage is at the rear, the 3 m and 7 m rules for two-storey rear extensions apply, measured from the original house. A householder application costs £548 (or £575 for applications made from 8 December 2026).

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

Matching the house

A room over a garage usually sits beside the front of the house in full view, so roof form, ridge height, windows and brick matter. Setting the front wall and ridge back slightly from the main house usually helps it look as if it belongs.

Fire separation

If the garage stays a garage, the floor between it and the room above, and any door into the house, must give fire separation under building regulations. That usually means fire-resisting plasterboard ceilings, sealed gaps and a fire door, which we design in from the start.

How we'd run your project

Look at the house
We start in Blyth with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
Plans, then approval
Measured survey, design, then the right approval route for your house. We explain each step before we take it.
Engineer it
Foundations sized for two floors, steels for any openings, and building control approval, all before anyone starts on site.
Build
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.

Questions about extensions over a garage in Blyth

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.

Who handles building regulations for a project in Blyth?

We handle it as part of the project. What's needed in England: building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.

How long does an extension over a garage 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.

Do I need to convert the garage as well?

No. You can keep the garage for parking or storage and build only the room above, as long as the floor between them and any door into the house meet fire separation rules. Converting the garage at the same time is often good value, because the walls and foundations may be upgraded anyway.

Can my garage take a room on top?

Sometimes, but it needs checking. Many garages are built on shallow footings with thin walls, designed only for a single storey. We dig a trial hole and inspect the walls, and the structural engineer decides whether to reuse them, strengthen them, underpin the footings or build new foundations inside the garage.

Nearby

We also cover places near Blyth, including:

Other extensions in Blyth

All two-storey extension services in Blyth · Extensions over a garage across Northumberland

Want a figure first? Try our guide price tool, then book a free visit to firm it up.