The Mirion blog
Types of Loft Conversion: Velux, Dormer and Hip-to-Gable Compared
The three main types of loft conversion explained — what each one involves, how much space you gain and which is right for your home in London.
Which loft conversion is right for your home?
The right loft conversion depends on your roof structure, how much head height you need and what you want from the space.
Velux (roof light) loft conversion
What it is: Roof windows installed flush with the existing roofline. No structural changes to the roof shape.
Best for: Homes with enough existing head height (usually 2.2m or more at the ridge).
Cost: £25,000 to £40,000 typically.
Dormer loft conversion
What it is: A box-shaped extension built out from the roof slope, creating a flat ceiling and vertical walls inside.
Best for: Homes that need more head height and usable floor area. The most popular type in London.
Cost: £35,000 to £55,000 typically.
Hip-to-gable loft conversion
What it is: The sloped end of the roof is replaced with a vertical wall, creating more internal space.
Best for: Semi-detached or end-of-terrace houses with a hipped roof.
Cost: £40,000 to £65,000 typically.
Which should you choose?
We survey your loft and tell you honestly which type works best — and what it would cost. There is no obligation and no pressure.