Two-storey wraparound extensions in County Londonderry

County Londonderry at a glance

Nation: Northern Ireland
Price region: Northern Ireland
Postcode areas: BT
Towns covered: 11 listed below, plus surrounding villages
Approval route: Planning permission is usually needed.
Site visits: Free, no obligation

What a two-storey wraparound extension involves

A two-storey wraparound extension suits a house with space both beside it and behind it, where you want to transform the layout rather than add a single room. You get one design for the whole L-shape, the planning application, structural design for the corner and the openings into the house, building regulations approval and the build, managed by us and carried out by vetted teams working under S&K.

The main places we list in County Londonderry are Derry (BT48), Coleraine (BT51), Limavady (BT49), Magherafelt (BT45), Portstewart (BT55) and Portrush (BT56). We cover the villages in between too.

Guide price in Northern Ireland

Our guide for Northern Ireland is £1,890–£2,600 per m² including VAT. On a project with an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space), that puts a two-storey wraparound extension in County Londonderry at roughly £106,000–£145,500. Steelwork for wide openings is the item most likely to move the figure; we'll know once the engineer has designed it.

Spec	Per m²	Typical project
Essential	£1,740–£2,390 per m²	£97,500–£133,500
Standard	£1,890–£2,600 per m²	£106,000–£145,500
Premium	£2,270–£3,120 per m²	£127,000–£174,500

Rules in Northern Ireland

In Northern Ireland, the permitted development allowance for two-storey extensions covers rear extensions of up to 3 m that stay 7 m from the rear boundary. A wraparound adds a side element on two floors, so it normally needs a planning application. The fee is £347 per dwelling, and councils aim for an average of 15 weeks for local applications.

Approval in Northern Ireland: Planning application for works to a house: £347. Councils aim to decide local applications within an average of 15 weeks; many take longer.

Building control: Building control approval from the local council under the Building Regulations (Northern Ireland), using the Technical Booklets.

There is no Party Wall Act in Northern Ireland. Shared walls and boundaries are a matter of title and common law, so we agree access and record conditions with neighbours before work starts.

Getting the design right

Phasing the build

A wraparound touches two sides of the house at once, so the kitchen and often the rear rooms are out of use for part of the build. We plan the sequence so you keep a working kitchen and bathroom for as long as possible, or advise when moving out briefly makes sense.

Two roofs that meet

A wraparound needs the side roof and rear roof to join cleanly, often with a valley or hip where they meet. Getting pitches and ridge heights right keeps rainwater moving and avoids a bulky mass at the back corner, which neighbours and planners notice.

How we work in County Londonderry

Measure and listen
A visit to County Londonderry to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Get it approved
Once you're happy with the design we submit it to the council for County Londonderry and deal with any questions from the planning officer.
Technical design
We prepare the building regulations drawings, structural calculations and specification so the build price can be fixed.
Finish and certify
Second fix, plastering and making good, then building control's final inspection and the completion paperwork.

Towns we cover in County Londonderry

Two-storey wraparound extensions in County Londonderry: questions

How much does a two-storey wraparound extension cost in County Londonderry?

In Northern Ireland our guide is £1,890–£2,600 per m² including VAT, so about £106,000–£145,500 for an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space). Essential and Premium specs move that by roughly 8% down or 20% up.

Does a wraparound extension need steel?

Almost always. Opening the corner of the house and the old rear wall to make one open-plan space means steel beams, and often a steel post or frame at the outside corner. The structural engineer sizes these, and the steel is ordered once the design is fixed, which is one reason a wraparound needs careful sequencing.

Can a wraparound extension be part single, part two-storey?

Yes. Many wraparounds keep the rear part single storey with roof lights over the kitchen and put the two-storey part to the side. This can reduce the effect on neighbours and the cost. We set out both options at the design stage, so you can compare floor space against price before choosing.

Is a wraparound extension better than separate side and rear extensions?

Building both at once usually costs less than two separate projects, because you pay for one set-up, one scaffold, one roof junction and one set of approvals. It also lets the layout be designed as a whole. The trade-off is a larger single outlay and a longer build, often 16 to 24 weeks at this size.

Will I need planning permission in County Londonderry?

County Londonderry is in Northern Ireland. Planning permission is usually needed.

Neighbouring areas

All extension services in County Londonderry · About two-storey wraparound extensions