What is a garden annexe?
A garden annexe is a single-storey building in the garden with its own living space, bathroom and often a kitchenette, used by relatives, older children or guests. Unlike a garden room, it is built as habitable accommodation with foundations, insulation and services.
How much does a garden annexe cost in Dumbarton?
In Dumbarton, a garden annexe typically costs £1,750–£2,700 per m² of floor area, including VAT at 20% (standard rate). For a typical 35 m² project that is roughly £61,000–£94,500. Building costs in Scotland are close to the UK average, so the figures for Dumbarton are close to our national guide. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (24 m²) | £42,000–£65,000 |
| Typical project (35 m²) | £61,000–£94,500 |
| Larger project (49 m²) | £86,000–£132,500 |
| Rate per m² | £1,750–£2,700 |
What moves the price most:
- Cladding and finishes
- Kitchen and bathroom
- Access for materials
- Size and layout
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a garden annexe in Dumbarton?
The approval route for Dumbarton is set by planning law in Scotland. In Scotland an annexe with living accommodation needs planning permission and a building warrant.
In Scotland a building warrant is needed before work starts on most extensions, loft conversions and conversions. It is issued by the council’s building standards service. When the work is finished, a completion certificate is submitted and accepted by the council after inspection.
We check this for your address before design work starts, so there are no surprises later.
What we handle
What we take care of:
- Building control sign-off
- Insulated walls and roof
- Kitchenette and shower room
- Electrics and heating
- Glazed doors and windows
- Planning drawings and application
How long does it take?
Allow 10 to 16 weeks on site. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Dumbarton
In Scotland, bungalows and one-and-a-half-storey homes are common, so dormer conversions are a popular way to add bedrooms.
Our Dumbarton coverage includes postcode districts G82, and we also work in nearby places such as Erskine, Clydebank and Greenock.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about garden annexes in Dumbarton
Do you build garden annexes in Dumbarton?
Yes. We build garden annexes across Dumbarton, including postcodes G82. Every project starts with a free home visit.
Does it need building regulations?
Yes, as it contains sleeping accommodation and services.
Do I need planning permission for a garden annexe in Dumbarton?
In Scotland an annexe with living accommodation needs planning permission and a building warrant.
How much does a garden annexe cost in Dumbarton?
In Dumbarton, a garden annexe typically costs £1,750–£2,700 per m² of floor area, including VAT at 20% (standard rate). A typical 35 m² project comes to roughly £61,000–£94,500. Your fixed price depends on the survey and drawings.
Can an annexe be rented out?
Not without further planning permission, as that would make it a separate dwelling.
How long does it take?
Typically 10 to 16 weeks on site.