What is a rooflight loft conversion?
A rooflight loft conversion (sometimes called a roof window conversion) keeps the existing roof shape and adds roof windows that sit flush with the slope. The floor is strengthened, a staircase is added and the space is insulated and finished.
How much does a rooflight loft conversion cost in County Antrim?
In County Antrim, a rooflight loft conversion typically costs £26,000–£38,500 for a typical rooflight conversion, including VAT at 20% (standard rate). We start from a UK-wide guide and adjust it for Northern Ireland, where labour and materials are typically about 14% below average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rooflight conversion | £26,000–£38,500 |
| Higher specification | £38,500–£48,000 |
Your quote will depend mainly on:
- Fire safety upgrades
- Bathroom or not
- Storage and finishes
- Floor and roof strengthening
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a rooflight loft conversion in County Antrim?
Before anything is built in County Antrim, we confirm which approvals apply in Northern Ireland. In Northern Ireland roof windows that project no more than 15 centimetres from a road-facing roof slope are permitted development outside conservation areas; listed buildings need consent.
In Northern Ireland building control approval comes from the council, usually through a full plans application or a building notice, with inspections during the work and a completion certificate at the end.
We check this for your address before design work starts, so there are no surprises later.
What we handle
What we take care of:
- Building control sign-off
- Roof windows installed
- Head-height survey
- Insulation between and under rafters
- Electrics, heating and plastering
- Staircase and fire-safe escape route
How long does it take?
Allow 4 to 6 weeks on site. Before that, surveys, drawings and approvals usually take 6 to 12 weeks, longer if the council asks for changes.
Building in County Antrim
Across Northern Ireland, bungalows and chalet bungalows are common, so loft conversions and rear extensions are popular projects.
Towns we cover in County Antrim include Belfast, Lisburn, Newtownabbey, Carrickfergus, Ballymena and Antrim.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about rooflight loft conversions in County Antrim
How long does a rooflight loft conversion take in County Antrim?
Typically 4 to 6 weeks on site. Design and approvals beforehand usually take 6 to 12 weeks.
Do I need planning permission for a rooflight loft conversion in County Antrim?
In Northern Ireland roof windows that project no more than 15 centimetres from a road-facing roof slope are permitted development outside conservation areas; listed buildings need consent.
How much does a rooflight loft conversion cost in County Antrim?
In County Antrim, a rooflight loft conversion typically costs £26,000–£38,500 for a typical rooflight conversion, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
Can I have a bathroom?
Yes, where there is enough head height at the shower or bath position.
How much head height do I need?
Around 2.2 metres or more from the top of the ceiling joists to the ridge is a good starting point. Insulation and new floor joists reduce the height.
What about fire safety?
The same escape rules apply as for any loft conversion, so a protected stairway and smoke alarms are typically needed.