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 Belfast?
In Belfast, a rooflight loft conversion typically costs £26,000–£38,500 for a typical rooflight conversion, including VAT at 20% (standard rate). Prices across Northern Ireland are typically 14% below the UK average for this kind of work, which is reflected in the range for Belfast. 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 |
What moves the price most:
- Fire safety upgrades
- Floor and roof strengthening
- Storage and finishes
- Number of roof windows
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a rooflight loft conversion in Belfast?
The approval route for Belfast is set by planning law 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.
Northern Ireland has no Party Wall Act. Work on shared walls relies on agreement with the neighbour and common law, so we agree the arrangements in writing before work starts.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
Handled as part of most rooflight loft conversions:
- Electrics, heating and plastering
- Head-height survey
- Drawings and structural calculations
- Floor joists and any steel beams
- Building control sign-off
- Staircase and fire-safe escape route
How long does it take?
Build time is typically 4 to 6 weeks on site. Design and approvals come first and typically take 6 to 12 weeks, depending on the approval route.
Building in Belfast
Northern Ireland has many detached and semi-detached homes on generous plots, which suits single-storey rear extensions and garage conversions.
We work across Belfast and neighbouring areas such as Newtownabbey, Lisburn and Newtownards. Postcodes we cover in Belfast include BT1, BT2, BT3 and BT4.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about rooflight loft conversions in Belfast
What about fire safety?
The same escape rules apply as for any loft conversion, so a protected stairway and smoke alarms are typically needed.
Is it cheaper than a dormer?
Yes, usually, because the roof shape stays the same. But you gain less full-height floor space.
Who approves a rooflight loft conversion in Belfast?
Planning matters in Belfast go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
Do I need planning permission for a rooflight loft conversion in Belfast?
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 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.
How much does a rooflight loft conversion cost in Belfast?
In Belfast, 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.