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 Down?
In County Down, a rooflight loft conversion typically costs £26,000–£38,500 for a typical rooflight conversion, including VAT at 20% (standard rate). That range is adjusted for Northern Ireland, where domestic building work typically costs around 14% below the national 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 |
The biggest cost drivers are:
- Fire safety upgrades
- Staircase position
- Storage and finishes
- Bathroom or not
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a rooflight loft conversion in County Down?
Approvals for a rooflight loft conversion in County Down follow the rules for 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.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
The work we manage on a rooflight loft conversion:
- Insulation between and under rafters
- Floor joists and any steel beams
- Drawings and structural calculations
- Electrics, heating and plastering
- Roof windows installed
- Building control sign-off
How long does it take?
The build itself usually takes 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 Down
Northern Ireland has many detached and semi-detached homes on generous plots, which suits single-storey rear extensions and garage conversions.
Towns we cover in County Down include Bangor, Newtownards, Newry, Banbridge and Downpatrick.
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 pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about rooflight loft conversions in County Down
What about fire safety?
The same escape rules apply as for any loft conversion, so a protected stairway and smoke alarms are typically needed.
Who approves a rooflight loft conversion in County Down?
Planning matters in County Down go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
Is it cheaper than a dormer?
Yes, usually, because the roof shape stays the same. But you gain less full-height floor space.
Can I have a bathroom?
Yes, where there is enough head height at the shower or bath position.
Do I need planning permission for a rooflight loft conversion in County Down?
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 Down?
In County Down, 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.