Double-storey extensions in Dumbarton: design, approvals and build
If you live in Dumbarton and want more space without moving, a double-storey extension is one of the most practical ways to get it. We handle the drawings, approvals and the build.
- Guide price in DumbartonFrom £37,000 inc VAT
- PlanningUsually planning permission; building warrant needed
- Build time16–24 weeks on site
- Postcode districtsG82
When a double-storey extension makes sense
- Growing families who need a bedroom as well as a bigger kitchen
- Houses with enough distance to the rear or side boundary
- Homeowners who would otherwise consider moving
The roof is what makes a two-storey extension look right or wrong. We match the pitch and materials of the main house wherever possible and plan the upstairs layout around the existing landing so the new rooms feel original rather than bolted on.
How much does a double-storey extension cost in Dumbarton?
For Dumbarton 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 Dumbarton: £1,520 to £2,940 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m, two floors 24 m² | £37,000 – £44,500 | £42,000 – £55,500 | £54,000 – £71,000 |
| 4 m × 4 m, two floors 32 m² | £48,500 – £58,500 | £56,000 – £74,000 | £72,000 – £94,500 |
| 4 m × 6 m, two floors 48 m² | £72,500 – £87,500 | £84,500 – £111,000 | £108,000 – £141,500 |
For a figure based on your own dimensions, use our guide-price tool.
Working in Dumbarton
We cover Dumbarton and the postcode districts G82. Neighbouring towns we cover include Vale of Leven (2 miles), Clydebank (7 miles), Bearsden (9 miles), Bishopbriggs (14 miles).
Erskine, in Renfrewshire and Inverclyde, is roughly 6 miles from Dumbarton and also on our list. Scotland's housing includes sandstone villas, terraces and tenements in the cities and plenty of post-war and modern houses and bungalows elsewhere. A building warrant is needed before work starts.
Planning rules that apply in Dumbarton
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.
Homes in conservation areas, national scenic areas and listed buildings have tighter rules, so we always check the property's status and planning history before design starts.
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.
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
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Double-storey extension questions answered
Do I need building regulations approval in Dumbarton?
Yes. Almost every extension needs it, whatever the planning route. In Scotland that means a building warrant before work starts.
Who do I contract with for a double-storey extension in Dumbarton?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
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.
Is a two-storey extension cheaper per square metre?
Usually. Our guide range is about £1,520 to £2,940 per m² of new floor area including VAT, compared with £1,720 to £3,330 per m² for single-storey work, because the foundations and roof are shared across two floors.
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.