Side return extensions in Derry/Londonderry
We design and build side return extensions for houses in Derry/Londonderry, with a written price once the survey and design are done and one point of contact throughout.
- Guide price in Derry/LondonderryFrom £15,000 inc VAT
- PlanningDepends on the NI limits; checked at the survey
- Build time10–14 weeks on site
- Postcode districtsBT48

Included in a typical project
- Design to keep daylight in the middle of the house
- Kitchen-ready shell or full finish
- Glazed, sloping or flat roof with rooflights
- Survey of the outrigger, boundary wall and drainage
- Removal of the side wall and new steelwork
Side return extension prices in Derry/Londonderry
For Derry/Londonderry we adjust our national guide rates by ×0.86, the factor we use for Northern Ireland. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Derry/Londonderry: £1,810 to £3,270 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 1.8 m × 4.5 m 8 m² | £15,000 – £18,500 | £16,500 – £21,000 | £20,500 – £26,500 |
| 2 m × 5.5 m 11 m² | £19,500 – £24,000 | £22,500 – £28,500 | £28,000 – £36,000 |
| 2.2 m × 7 m 15 m² | £27,000 – £32,500 | £30,500 – £39,000 | £38,500 – £49,500 |
Try the guide-price tool to see a range for your own size and finish.
Covering Derry/Londonderry
Postcode districts we cover around Derry/Londonderry include BT48. We also work in nearby Limavady (15 miles), Coleraine (27 miles), Magherafelt (31 miles).
Northern Ireland's housing ranges from city terraces to large numbers of detached houses and bungalows on rural plots, many in render, where single-storey extensions fit easily.
Do I need planning permission in Derry/Londonderry?
In Northern Ireland the Planning (General Permitted Development) Order 2015 lets some single-storey rear extensions go ahead without planning permission, up to 3 m on a semi-detached or terraced house and 4 m on a detached house, within height and boundary limits. Larger, side and two-storey extensions normally need planning permission from the council, and building control approval is separate.
The planning position for a specific Derry/Londonderry address depends on its history and any designations, which is why we check it at the first visit.
Northern Ireland has no Party Wall Act. Where work is on or close to a shared boundary, we agree access and protection with your neighbour in writing before work starts.
Building close to a public sewer needs the agreement of NI Water, which we check during design.
Applications are decided by your council, which handles local planning in Northern Ireland.
Our process, step by step
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Your questions about a side return extension in Derry/Londonderry
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Derry/Londonderry, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Who do I contract with for a side return extension in Derry/Londonderry?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Do you cover all of Derry/Londonderry?
Yes. We cover Derry/Londonderry and the surrounding parts of County Londonderry. Site visits are free and there is no obligation.
Can I combine a side return with a rear extension?
Yes. That combination is a wraparound extension, which adds the most space to a terraced house.
How much does a side return extension cost?
Our guide range is about £1,810 to £3,270 per m² including VAT, so a typical 2 m × 5.5 m infill lands around £22,500 to £28,500 at standard spec in Derry/Londonderry, more in London.
Book a free site visit in Derry/Londonderry
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.