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 Brecon?
In Brecon, a garden annexe typically costs £1,650–£2,600 per m² of floor area, including VAT at 20% (standard rate). For a typical 35 m² project that is roughly £58,000–£91,000. Prices across Wales are typically 8% below the UK average for this kind of work, which is reflected in the range for Brecon. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (24 m²) | £39,500–£62,500 |
| Typical project (35 m²) | £58,000–£91,000 |
| Larger project (49 m²) | £81,000–£127,500 |
| Rate per m² | £1,650–£2,600 |
The biggest cost drivers are:
- Cladding and finishes
- Kitchen and bathroom
- Size and layout
- Access for materials
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a garden annexe in Brecon?
Whether you need planning permission depends on your house and its location in Wales. In Wales an annexe with sleeping accommodation usually needs planning permission; outbuildings under permitted development must be incidental to the house.
Building regulations in Wales are set by the Welsh Government. Approval comes from the council’s building control service or a registered building control approver, with inspections during the work and a completion certificate at the end.
We check this for your address before design work starts, so there are no surprises later.
What we handle
On a typical garden annexe we handle:
- Building control sign-off
- Glazed doors and windows
- Electrics and heating
- Foundations and drainage connections
- External cladding or brickwork
- Insulated walls and roof
How long does it take?
The build itself usually takes 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 Brecon
Terraced houses in Welsh towns often have narrow plots, which suits rear and side return extensions and rear dormers.
Brecon sits in Powys, about 33 miles north-east of Swansea. We cover the whole of Brecon, including postcodes LD3.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about garden annexes in Brecon
Can an annexe be rented out?
Not without further planning permission, as that would make it a separate dwelling.
How long does a garden annexe take in Brecon?
Typically 10 to 16 weeks on site. Design and approvals beforehand usually take 3 to 4 months.
Does it need building regulations?
Yes, as it contains sleeping accommodation and services.
Can it be accessible?
Yes. Level access, wider doors and a wet room can be designed in.
Do I need planning permission for a garden annexe in Brecon?
In Wales an annexe with sleeping accommodation usually needs planning permission; outbuildings under permitted development must be incidental to the house.
How much does a garden annexe cost in Brecon?
In Brecon, a garden annexe typically costs £1,650–£2,600 per m² of floor area, including VAT at 20% (standard rate). A typical 35 m² project comes to roughly £58,000–£91,000. Your fixed price depends on the survey and drawings.