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 property. 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. In addition, it is possible to create a gable front and a hipped roof dormer to make it look more attractive, however these types of dormers do not offer as much internal space. Additionally, due to the added complexity, a gable front and hipped roof dormer will cost more to build. The l-shaped dormer loft conversion is also very popular and is often considered the best way to extend a mid-terrace period property to maximize space as it can give around 40m3 of space or slightly more under planning.
Advantage: Normally a dormer loft conversion can be constructed without gaining planning permission, although planning permission may be required depending on the specifications.