Bedroom extensions across Dumbarton
We design and build bedroom extensions for houses in Dumbarton, with a written price once the survey and design are done and one point of contact throughout.
- Guide price in DumbartonFrom £25,000 inc VAT
- PlanningUsually planning permission; building warrant needed
- Build time14–22 weeks on site
- Postcode districtsG82

Covering Dumbarton
Site visits are available across Dumbarton (G82). The same team covers Vale of Leven (2 miles), Clydebank (7 miles), Bearsden (9 miles), Bishopbriggs (14 miles), all within easy reach.
Just over the Renfrewshire and Inverclyde border, Erskine is about 6 miles away. 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 and approvals 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.
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.
Bedroom extension prices in Dumbarton
Labour and material costs vary across the UK, so for Dumbarton we use our Scotland factor (×0.98). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Dumbarton: £1,570 to £3,140 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| One bedroom 12 m² | £25,000 – £31,500 | £25,000 – £33,000 | £28,000 – £38,000 |
| Bedroom and en-suite 18 m² | £28,000 – £34,500 | £33,500 – £43,500 | £42,000 – £56,500 |
| Two rooms 30 m² | £47,000 – £57,500 | £55,500 – £72,500 | £70,500 – £94,500 |
For a figure based on your own dimensions, use our guide-price tool.
When a bedroom extension makes sense
- Multi-generational households
- Growing families
- Homeowners who want an en-suite master bedroom
New bedrooms on an upper floor need an escape window or a protected route to the outside under the building regulations. We design the window sizes and stair route to meet that from the outset.
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
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Questions people ask about bedroom extensions
Do you cover all of Dumbarton?
Yes. We cover Dumbarton and the surrounding parts of Dunbartonshire. Site visits are free and there is no obligation.
Who do I contract with for a bedroom 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.
How long does a bedroom extension take to build in Dumbarton?
On site, typically 14 to 22 weeks once approvals are in place. Before that, allow 8–14 weeks design and approvals.
How much does a bedroom extension cost?
Our guide range is about £1,570 to £3,140 per m² including VAT. A bedroom with an en-suite of about 18 m² is typically £33,500 to £43,500 at standard spec, depending on whether it is part of a larger two-storey build.
Does an en-suite need a window?
No, but it needs mechanical extraction that meets the building regulations. We design the duct route at the drawing stage.
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.