If you're planning a loft conversion, one of the key early decisions is whether to go with Velux (rooflight) windows or to build a dormer extension. Both have their merits — here's a clear comparison to help you decide.
Velux Windows
Velux windows are installed flush with the existing roof slope. They flood the room with natural light, including sky views, and are the most affordable option. However, they don't increase headroom or floor space — the existing roof profile is preserved. Best suited to lofts with good existing headroom (2.2m+).
Dormer Windows
A dormer extends the roof to create a box with vertical walls and a new window. This significantly increases headroom, usable floor space, and the amount of light entering from a vertical window. Dormers cost more and take longer to build, but create a more usable, roomier space.
Light Quality
Both types provide excellent natural light. Velux windows give you sky views and direct sunlight throughout the day as the sun moves. Dormer windows provide more horizontal, constant light — similar to a standard room window. Many clients opt for a combination: a dormer plus one or two Velux windows.
Planning and Cost
Velux conversions almost never require planning permission and cost £30,000–£40,000. Dormers occasionally require planning permission and cost £45,000–£65,000. If budget is the primary consideration, Velux wins. If space and versatility matter more, dormer is the better choice.
Ready to Get Started?
Can't decide? Our surveyors will assess your loft and recommend the best solution for your specific home, headroom and budget. Book your free survey by calling 01279 218410.
Essex Loft Extensions Team
Based in Harlow, Essex · 40 years experience · 01279 218410
