What is a side return extension?
A side return extension fills the narrow passage that runs alongside the back addition of many Victorian and Edwardian terraced houses. It widens a galley kitchen into a proper kitchen-diner, usually with a sloping glazed roof to keep the room bright.
How much does a side return extension cost in Antrim?
In Antrim, a side return extension typically costs £2,000–£2,850 per m² of floor area, including VAT at 20% (standard rate). For a typical 12 m² project that is roughly £24,000–£34,000. That range is adjusted for Northern Ireland, where domestic building work typically costs around 14% below the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (8 m²) | £16,000–£23,000 |
| Typical project (12 m²) | £24,000–£34,000 |
| Larger project (17 m²) | £34,000–£48,500 |
| Rate per m² | £2,000–£2,850 |
The biggest cost drivers are:
- Moving drains and soil stacks
- Length of the side return
- Steel beams and propping of the back addition
- Access through the house for materials
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a side return extension in Antrim?
Here is how the rules work for a side return extension in Northern Ireland. In Northern Ireland a single-storey side infill can be permitted development if it is no more than 4 metres high and no wider than half the original house; conservation areas need planning permission. Building control approval is needed before work starts.
In Northern Ireland building control approval comes from the council, usually through a full plans application or a building notice, with inspections during the work and a completion certificate at the end.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
Handled as part of most side return extensions:
- Building control sign-off
- Drawings and planning or permitted development check
- Floor levelling, heating and electrics
- Foundations and drainage, including any build-over agreement
- Steel beams to remove the side wall
- Glazed or solid roof with insulation
How long does it take?
Allow 10 to 14 weeks on site. Design and approvals come first and typically take 3 to 4 months, depending on the approval route.
Building in Antrim
Northern Ireland has many detached and semi-detached homes on generous plots, which suits single-storey rear extensions and garage conversions.
Our Antrim coverage includes postcode districts BT41, and we also work in nearby places such as Ballymena, Newtownabbey and Belfast.
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 handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about side return extensions in Antrim
Is a glass roof too hot or cold?
Modern solar-control double or triple glazing reduces glare and heat loss. Building regulations also limit how much glazing you can have unless the design shows it performs well enough.
How do you get materials in?
Mid-terrace houses often have no rear access, so materials come through the house. We protect floors and plan deliveries carefully.
How much does a side return extension cost in Antrim?
In Antrim, a side return extension typically costs £2,000–£2,850 per m² of floor area, including VAT at 20% (standard rate). A typical 12 m² project comes to roughly £24,000–£34,000. Your fixed price depends on the survey and drawings.
Who approves a side return extension in Antrim?
Planning matters in Antrim go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
How much space does a side return add?
Typically 1.5 to 2.5 metres of width along the back addition. It often turns a narrow galley kitchen into a family kitchen-diner.
Do I need planning permission for a side return extension in Antrim?
In Northern Ireland a single-storey side infill can be permitted development if it is no more than 4 metres high and no wider than half the original house; conservation areas need planning permission. Building control approval is needed before work starts.