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 Northumberland?
In Northumberland, a rooflight loft conversion typically costs £27,000–£40,500 for a typical rooflight conversion, including VAT at 20% (standard rate). We start from a UK-wide guide and adjust it for the North East, where labour and materials are typically about 10% below average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rooflight conversion | £27,000–£40,500 |
| Higher specification | £40,500–£50,500 |
The biggest cost drivers are:
- Bathroom or not
- Staircase position
- Number of roof windows
- Floor and roof strengthening
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a rooflight loft conversion in Northumberland?
Approvals for a rooflight loft conversion in Northumberland follow the rules for England. In England roof windows are permitted development if they project no more than 15 centimetres from the roof slope and side-facing windows are obscure-glazed. Listed buildings need consent.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
Handled as part of most rooflight loft conversions:
- Insulation between and under rafters
- Floor joists and any steel beams
- Staircase and fire-safe escape route
- Drawings and structural calculations
- Roof windows installed
- Building control sign-off
How long does it take?
Allow 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 Northumberland
The North East has many terraced streets and post-war semis, where rear extensions and loft conversions are popular ways to gain space.
Towns we cover in Northumberland include Blyth, Cramlington, Ashington and Bedlington.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about rooflight loft conversions in Northumberland
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 Northumberland?
Planning matters in Northumberland go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
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.
Can I have a bathroom?
Yes, where there is enough head height at the shower or bath position.
How much does a rooflight loft conversion cost in Northumberland?
In Northumberland, a rooflight loft conversion typically costs £27,000–£40,500 for a typical rooflight conversion, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
