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 Larne?
In Larne, 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. The guide for Larne reflects typical costs in Northern Ireland, roughly 14% below the UK-wide figure. 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 |
Your quote will depend mainly on:
- Access through the house for materials
- Agreements with neighbours on shared walls
- Moving drains and soil stacks
- Glazed roof specification
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 side return extension in Larne?
The approval route for Larne is set by planning law 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.
Northern Ireland has no Party Wall Act. Work on shared walls relies on agreement with the neighbour and common law, so we agree the arrangements in writing before work starts.
We check this for your address before design work starts, so there are no surprises later.
What we handle
From survey to sign-off, the job normally involves:
- Floor levelling, heating and electrics
- Foundations and drainage, including any build-over agreement
- Drawings and planning or permitted development check
- Written agreement with neighbours on shared walls
- Glazed or solid roof with insulation
- Steel beams to remove the side wall
How long does it take?
The build itself usually takes 10 to 14 weeks on site. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Larne
Across Northern Ireland, bungalows and chalet bungalows are common, so loft conversions and rear extensions are popular projects.
Our Larne coverage includes postcode districts BT40, and we also work in nearby places such as Carrickfergus, Newtownabbey and Bangor.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 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 Larne
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.
Do I need planning permission for a side return extension in Larne?
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.
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.
How much does a side return extension cost in Larne?
In Larne, 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.
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 long does a side return extension take in Larne?
Typically 10 to 14 weeks on site. Design and approvals beforehand usually take 3 to 4 months.
