Two-storey rear extensions in Portstewart
Adding a two-storey rear extension in Portstewart gives you two new rooms stacked on one footprint. Here's how we'd approach it, what it typically costs and the rules that apply in Northern Ireland.
The basics for Portstewart at a glance.
- Postcode districts
- BT55
- County / area
- County Londonderry, Northern Ireland
- Price region
- Northern Ireland
- Guide price
- £49,500–£66,500 (£1,760–£2,380 per m²)
- Approval route
- It may be permitted development if it goes no more than 3 m beyond the original rear wall and stays 7 m from the rear boundary.
- Nearest towns
- Portrush (2.7 miles), Coleraine (3.8 miles), Ballymoney (11.1 miles)
- Distance to Derry
- about 26.8 miles
- First visit
- Free, no obligation
About a two-storey rear extension
A two-storey rear extension suits you if you need more room on both floors and have a reasonably deep garden. You get one team for the whole job: a measured survey, the design, a check on whether permitted development applies, planning drawings where they are needed, structural design, building regulations approval and the build itself, carried out by vetted teams working under S&K. Every project starts with a free site visit.
Portstewart sits about 26.8 miles from Derry. Closer to home, Portrush is 2.7 miles away and Coleraine 3.8 miles.
What it costs in Portstewart
Guide prices for two-storey rear extensions in Northern Ireland are around £1,760–£2,380 per m² of new floor space, including VAT. For a typical project with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space), that's roughly £49,500–£66,500. Professional fees for drawings and the structural engineer are listed separately on our prices page.
| Spec | Per m² | A 4 m × 3.5 m footprint on two floors (28 m² of new floor space) |
|---|---|---|
| Essential | £1,620–£2,190 per m² | £45,500–£61,000 |
| Standard | £1,760–£2,380 per m² | £49,500–£66,500 |
| Premium | £2,110–£2,850 per m² | £59,000–£80,000 |
Planning and building control in Portstewart
In Northern Ireland, a two-storey rear extension can be permitted development if it goes no more than 3 m beyond the original rear wall and stays at least 7 m from the rear boundary, with conditions on height, materials and roof pitch. Upper side windows within 15 m of a neighbouring boundary must be obscure-glazed and non-opening. Otherwise a planning application costs £347 per dwelling.
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.
Design points for Portstewart homes
Opening up the ground floor
Knocking through the old rear wall means steel beams to carry the first floor and roof above. The structural engineer sets the beam sizes, padstones and any posts, and we plan them early so the open-plan layout you want is the one that gets built.
Depth and neighbours' light
Councils check that a two-storey rear extension does not take too much light or outlook from neighbouring windows, and many use a 45-degree line drawn from the nearest habitable window. We test this at sketch stage, so the depth you are shown is one that can realistically be approved.
How we'd run your project
Understand the brief
At your home in Portstewart we agree what you need: bedroom count, bathroom, kitchen space, and how much garden you want to keep.
Drawings, then consent
We draw the scheme, check it against the rules in Northern Ireland, and take it through the right consent with the council.
Technical design
We prepare the building regulations drawings, structural calculations and specification so the build price can be fixed.
Build it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.
Questions about two-storey rear extensions in Portstewart
Which postcodes do you cover around Portstewart?
We cover Portstewart (BT55) and nearby places including Portrush, Coleraine and Ballymoney, plus the rest of County Londonderry. The first site visit is free.
Who handles building control for a project in Portstewart?
We handle it as part of the project. What's needed in Northern Ireland: building control approval from the local council under the Building Regulations (Northern Ireland), using the Technical Booklets. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.
How long does a two-storey rear extension take?
Allow 4 to 8 weeks for survey and design, then the approval period (councils aim to decide local applications within an average of 15 weeks; many take longer), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.
Do I need planning permission for a two-storey rear extension in Portstewart?
Portstewart is in Northern Ireland. It may be permitted development if it goes no more than 3 m beyond the original rear wall and stays 7 m from the rear boundary.
Will a two-storey rear extension block my neighbour's light?
It can if it is too deep or too close to the boundary, which is why councils look closely at its effect on neighbouring windows and gardens. We test the design against light and outlook early, keep the first floor shorter or set in where needed, and use a hipped roof to reduce bulk on the boundary side.
Nearby
Close to Portstewart? We work across the area, including:
Other extensions in Portstewart
- Side
- Wraparound
- Part two-storey
- Over a garage
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Portstewart · Two-storey rear extensions across County Londonderry
Send us your postcode and a few details. We'll get back to you to arrange a visit and talk through your options.