A dormer is a window set vertically into a small gable projecting from a sloping roof. This type of conversion allows a larger area of space to be created. If lofts require more than one room in them, for example a single bedroom also with an en-suite bathroom, then this conversion is usually better suited and used where possible. 

Dormer Loft Conversion

Web Design by Millie Hood

A dormer conversion from outside

A dormer conversion diagram