Extensions over a garage for homes in Renfrew
A over-garage extension in Renfrew starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in RenfrewFrom £23,500 inc VAT
- PlanningPermission and a building warrant needed
- Build time12–18 weeks on site
- Postcode districtsPA1, PA4

Planning and approvals in Renfrew
In Scotland, householder permitted development rules (Class 1A for single-storey ground-floor extensions and Class 1B for extensions of more than one storey) allow some smaller extensions without a planning application, within limits on depth, height and distance from the boundary. Conservation areas and listed buildings are more restricted.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
Building close to a public sewer needs the agreement of Scottish Water, which we check during design.
In Scotland a building warrant from the council is needed before work starts on almost any extension, and a completion certificate is issued when the work is accepted. Building standards are set in the Scottish technical handbooks.
Applications are decided by your council as planning authority.
Guide prices for Renfrew
For Renfrew we adjust our national guide rates by ×0.98, the factor we use for Scotland. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Renfrew: £1,760 to £3,330 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Over a single garage 12 m² | £23,500 – £29,000 | £24,500 – £32,000 | £31,500 – £40,000 |
| Over a large single garage 16 m² | £28,000 – £34,500 | £32,500 – £42,500 | £42,000 – £53,500 |
| Over a double garage 24 m² | £42,000 – £52,000 | £49,000 – £64,000 | £63,500 – £80,000 |
For a figure based on your own dimensions, use our guide-price tool.
What we take care of
- New floor structure, walls and roof
- Strengthening or rebuilding the garage walls if needed
- Insulation, electrics, heating and finish
- Structural survey of garage walls and foundations
- Opening into the existing first floor
- Design and householder planning application
Fitting the new room to the existing landing is the planning puzzle inside the house. We design the connection first, then the roof, so the extension does not end up with awkward steps or a corridor through a bedroom.
Covering Renfrew
Our survey diary covers Renfrew, including PA1, PA4. The same team covers Erskine (3 miles), Paisley (3 miles), Barrhead (5 miles), Johnstone (6 miles), all within easy reach.
Across Scotland, extensions follow Scottish planning and building standards, including the building warrant process, which we build into the programme from the start.
Our process, step by step
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Over-garage extension questions answered
Do you cover all of Renfrew?
Yes. We cover Renfrew and the surrounding parts of Renfrewshire and Inverclyde. Site visits are free and there is no obligation.
Will my neighbours in Renfrew be involved?
If a planning application is needed, the council notifies neighbours. Where work is close to a shared boundary, we agree access and protection with them in writing.
How long does an over-garage extension take to build in Renfrew?
On site, typically 12 to 18 weeks once approvals are in place. Before that, allow 8–14 weeks design and approvals.
How much does a room over a garage cost?
Our guide range is about £1,760 to £3,330 per m² including VAT. A single-garage room of about 12 m² usually costs £24,500 to £32,000 at standard spec, more if the garage needs rebuilding.
Can my garage take the weight of a room on top?
Some can and some cannot. Many garages have a single-skin wall or shallow foundations. Our structural engineer checks this before we give a fixed price.
Book a free site visit in Renfrew
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.