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 Darlington?
In Darlington, a garden annexe typically costs £1,600–£2,500 per m² of floor area, including VAT at 20% (standard rate). For a typical 35 m² project that is roughly £56,000–£87,500. That range is adjusted for the North East, where domestic building work typically costs around 10% below the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (24 m²) | £38,500–£60,000 |
| Typical project (35 m²) | £56,000–£87,500 |
| Larger project (49 m²) | £78,500–£122,500 |
| Rate per m² | £1,600–£2,500 |
Your quote will depend mainly on:
- Size and layout
- Cladding and finishes
- Access for materials
- Drainage connection distance
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a garden annexe in Darlington?
Whether you need planning permission depends on your house and its location in England. In England an annexe used as living accommodation usually needs planning permission. Outbuildings built under permitted development must be incidental to the house, such as a gym or office, not a bedroom.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
What we take care of:
- Kitchenette and shower room
- Building control sign-off
- Electrics and heating
- Planning drawings and application
- External cladding or brickwork
- Foundations and drainage connections
How long does it take?
The build itself usually takes 10 to 16 weeks on site. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Darlington
Across the North East, colliery-era terraces and newer estates sit side by side, so the right project depends on the house type.
From DL3 outwards, we take on projects throughout Darlington and the surrounding parts of County Durham.
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
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about garden annexes in Darlington
Can it be accessible?
Yes. Level access, wider doors and a wet room can be designed in.
How much does a garden annexe cost in Darlington?
In Darlington, a garden annexe typically costs £1,600–£2,500 per m² of floor area, including VAT at 20% (standard rate). A typical 35 m² project comes to roughly £56,000–£87,500. Your fixed price depends on the survey and drawings.
Will council tax apply?
Annexes can be banded separately, though discounts or exemptions apply in some cases when occupied by family. Check with your council.
Does a garden annexe need planning permission?
Usually yes if it is used as living accommodation. Outbuildings under permitted development must be incidental to the house, such as a gym or office, not bedrooms.
How long does a garden annexe take in Darlington?
Typically 10 to 16 weeks on site. Design and approvals beforehand usually take 3 to 4 months.