A dormer loft conversion is an extension to the existing roof that projects vertically from a sloping roof, creating additional floor space and headroom within the house. Internally, a dormer has vertical walls and a horizontal ceiling. It is the most common type of loft conversion, as the flat roof dormers often add the maximum amount of additional space.
A major advantage of a dormer loft conversion is that it can often be constructed without gaining planning permission, although planning permission may be required depending on the specifications.
Full width flar roof dormers are the most common type of loft conversion.