Extensions over a garage in Renfrew
Our extensions over a garage service in Renfrew covers everything: measured survey, design, planning or permitted development checks, structural design, building control and the build itself.
Before you start in Renfrew, here's what applies.
- Postcode districts
- PA4
- County / area
- Renfrewshire and Inverclyde, Scotland
- Price region
- Scotland
- Guide price
- £29,500–£43,000 (£1,640–£2,400 per m²)
- Approval route
- Planning permission is usually needed: Class 1B permitted development only applies if every part of the extension is at least 10 m from all boundaries. A building warrant is needed before work starts.
- Nearest towns
- Clydebank (2.1 miles), Erskine (3 miles), Dalmuir (3 miles)
- Distance to Paisley
- about 3.2 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 Renfrew (PA4) and the places around it, including Clydebank (2.1 miles), Erskine (3.0 miles) and Dalmuir.
What it costs in Renfrew
Most of the cost of an extension over a garage is set by its size and specification. For Renfrew and the rest of Scotland, our guide is £1,640–£2,400 per m² including VAT, so about £29,500–£43,000 for 3 m × 6 m of new first-floor space (18 m²). Professional fees for drawings and the structural engineer are listed separately on our prices page.
| Spec | Per m² | 3 m × 6 m of new first-floor space (18 m²) |
|---|---|---|
| Essential | £1,510–£2,210 per m² | £27,000–£39,500 |
| Standard | £1,640–£2,400 per m² | £29,500–£43,000 |
| Premium | £1,970–£2,880 per m² | £35,500–£52,000 |
Planning and building standards in Renfrew
In Scotland, a room over a garage makes the extension more than one storey, so Class 1B applies, which needs at least 10 m to every boundary for permitted development. Attached garages are rarely that far from the boundary, so expect a householder application (£371, decided within two months) and a building warrant.
Approval in Scotland: Householder planning application: £371. Councils have two months to decide a local planning application.
Building standards: A building warrant from the council's building standards service before work starts, and a completion certificate at the end. Scotland uses its own Technical Handbooks.
Design points for Renfrew homes
Garage walls and the door opening
Garage walls are often a single skin of brick or block with piers, and the wide door opening needs a beam over it. Many over-garage extensions need new inner walls or a steel frame to carry the floor and to insulate properly, which we confirm before the design is fixed.
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 standards. 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
Free site visit
We visit your home in Renfrew, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Get it approved
Once you're happy with the design we submit it to the council for Renfrew and deal with any questions from the planning officer.
Engineer it
Foundations sized for two floors, steels for any openings, and a building warrant, all before anyone starts on site.
On site
One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.
Questions about extensions over a garage in Renfrew
Do I need planning permission for an extension over a garage in Renfrew?
Renfrew is in Scotland. Planning permission is usually needed: Class 1B permitted development only applies if every part of the extension is at least 10 m from all boundaries. A building warrant is needed before work starts.
How much does an extension over a garage cost in Renfrew?
Our guide for Scotland, which covers Renfrew, is £1,640–£2,400 per m² including VAT. A typical project with 3 m × 6 m of new first-floor space (18 m²) comes to about £29,500–£43,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.
Which postcodes do you cover around Renfrew?
We cover Renfrew (PA4) and nearby places including Clydebank, Erskine and Dalmuir, plus the rest of Renfrewshire and Inverclyde. The first site visit is free.
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
The same service in neighbouring towns:
Other extensions in Renfrew
- Rear
- Side
- Wraparound
- Part two-storey
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Renfrew · Extensions over a garage across Renfrewshire and Inverclyde
Tell us about your house in Renfrew and we'll call you back to arrange a free, no-obligation visit.