Double-storey extensions in Derry

Covering Derry

We work in Derry (BT47) and the places around it, including Strabane, Limavady and Coleraine.

Homes in County Londonderry

Across Northern Ireland you find city terraces, suburban semis and rural bungalows and farmhouses, so the right approach depends on the plot and the planning history.

What is a double-storey extension?

Two-storey work has to sit comfortably with the house and the neighbours, so most of the design effort goes into the roofline, window positions and how the new first floor connects to the landing. We handle the planning application, the structural design and the building control process, then build, roof and finish both floors.

Planning and building control applications to the council
Measured survey, design and planning drawings
Windows, insulation, plastering, electrics and plumbing

How much should I budget for a double-storey extension?

Use these ranges to budget for double-storey extensions; the survey turns them into a fixed price for the agreed specification.

Double-storey extensions	Guide price incl. VAT
Standard specification	£2,400 to £2,900 per m²
Good specification	£2,900 to £3,400 per m²
High specification	£3,400 to £3,850 per m²

Planning and building rules in Derry

Projects in Northern Ireland need planning clearance from one of the eleven councils and building control approval, also from the council. The Party Wall etc. Act does not extend to Northern Ireland, so work near neighbours is agreed directly and documented carefully.

Two-storey extensions in Northern Ireland normally need planning permission from the council, plus building control approval.

What should Derry homeowners check first?

Side extensions close to a boundary are often set back or stepped down so they do not create a terraced effect.
Neighbours’ light is assessed using the 45-degree guide many councils use.

What happens after I enquire?

Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.

What people ask before starting

How much does a two-storey extension cost?

Typically about £2,400 to £3,850 per square metre of new floor area including VAT. A 40 m² extension across two floors is often around £100,000 to £150,000 depending on specification.

Will we need to move out?

Most people stay. The noisiest stage is when we break through into the existing first floor, which we plan for a short window.

Who deals with the council for a project in Derry?

We do. We prepare the drawings, submit planning or permitted development paperwork if needed, and arrange building control inspections.

Double-storey extensions near Derry

Learn more about double-storey extensions, or see every project we cover in Derry.