Single-storey rear extensions in Dumbarton: design, approvals and build
From the first sketch to final sign-off, we plan and build single-storey extensions in Dumbarton and the surrounding Dunbartonshire area.
- Guide price in DumbartonFrom £20,500 inc VAT
- PlanningScottish householder rules; building warrant needed
- Build time10–16 weeks on site
- Postcode districtsG82
Will the council need to approve it?
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. Separately, almost every extension needs a building warrant from the council before work starts.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
Scotland has no Party Wall Act. Where work affects a shared wall or a neighbour's land, we agree access, protection and making good with your neighbour in writing before work starts.
Applications are decided by your council as planning authority.
When a single-storey extension makes sense
- Homeowners who want open-plan living onto the garden
- Semi-detached and detached houses with a usable rear garden
- Terraced houses that want a deeper kitchen across the full width
What should I budget for a single-storey extension in Dumbarton?
These guide figures apply our Scotland adjustment (×0.98) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Dumbarton: £1,720 to £3,330 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £20,500 – £24,500 | £24,000 – £31,000 | £30,500 – £40,000 |
| 4 m × 5 m 20 m² | £34,000 – £40,500 | £40,000 – £51,000 | £50,500 – £67,000 |
| 5 m × 6 m 30 m² | £51,000 – £60,500 | £60,000 – £76,500 | £76,000 – £100,000 |
For a figure based on your own dimensions, use our guide-price tool.
Extensions in and around Dumbarton
Our survey diary covers Dumbarton, including G82. The same team covers Vale of Leven (2 miles), Clydebank (7 miles), Bearsden (9 miles), Bishopbriggs (14 miles), all within easy reach.
Erskine, in Renfrewshire and Inverclyde, is roughly 6 miles from Dumbarton and also on our list. Across Scotland, extensions follow Scottish planning and building standards, including the building warrant process, which we build into the programme from the start.
How the project works
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
We visit your Dumbarton home, measure up, talk through what you want and check the planning position.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Your questions about a single-storey extension in Dumbarton
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Dumbarton, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Will my neighbours in Dumbarton 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 a single-storey extension take to build in Dumbarton?
On site, typically 10 to 16 weeks once approvals are in place. Before that, allow 4–12 weeks design and approvals.
How much does a single-storey extension cost per square metre?
Our guide range is about £1,720 to £3,330 per m² including VAT, depending on specification. A standard-spec 4 m × 5 m room usually lands at £40,000 to £51,000 in Dumbarton, plus design and council fees.
Can I stay in the house during the build?
Usually yes. Most of the work happens outside until the final weeks, when we open the rear wall. We plan that stage carefully and seal the opening with a temporary screen to keep dust down.
Book a free site visit in Dumbarton
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.