Velux and rooflight loft conversions — the simplest, lowest-cost loft conversion when the existing roof has enough headroom. No external structural change, no planning needed, minimal disruption.
When a Velux Conversion Works
The Velux (or "rooflight") conversion adds rooflights to the existing roof slope without changing the roof line. It's the right answer when:
- The existing roof has enough ridge height (typically 2.4m clear at the apex)
- You don't need the full footprint of a dormer's flat ceiling
- Permitted development is unavailable or you want to avoid planning entirely (rooflights don't typically require permission)
- Budget is tighter than a dormer build
What You Get
A converted loft room with sloping ceilings on either side (following the existing roof), useable floor space across the middle, and 2–4 Velux windows providing light and ventilation. Typically used as a:
- Bedroom (smaller than a dormer room — usually a single or small double)
- Study or home office
- Playroom or den
- Storage and seating (for low-ridge houses)
Cost & Timeline
Velux loft conversions in Barnet typically cost £18,000–£30,000. They take 4–6 weeks on site, with no roof-off phase — so far less disruption than a dormer.
Included in the quote:
- Structural floor (joist upgrade where required)
- Velux windows (typically 2–4 standard or top-hung)
- Insulation to current Part L
- Plasterboard, electrics, heating
- New staircase or staircase extension
- Decoration and flooring
- Building Control sign-off
The Catch
The ceiling on either side of a Velux conversion follows the roof slope. Useable head height (anything above 1.5m) is concentrated in the middle. For a true full-height room you need a dormer. For a useable extra room at half the price — Velux is the answer.
Frequently Asked Questions
Do I need planning permission?
Almost never. Rooflights on the existing roof slope, not projecting more than 150mm, are universally permitted development. Conservation areas may need additional consent — check on the survey.
How much head height do I need?
A useable Velux conversion needs roughly 2.4m clear at the ridge, dropping to about 1.5m at the eaves. The carpenter measures on the survey.
Can I add a bathroom?
Yes, but it's tight — partitioning out an en-suite in a Velux loft is feasible but the slopes mean you'll have a low-ceilinged shower area. Most clients prefer to skip the bathroom in Velux conversions.
Why is it cheaper than a dormer?
No external structural change to the roof, no scaffolding for roof-off works, no new tiling, no new vertical walls. Most of the cost saving is in the structural phase.