The word Garret comes from the same root as the word garrison. It is used to describe a habitable attic space (somewhere that, in the past, guards or soldiers may have been quartered).
In modern times, a Garret describes any loft space that has been made habitable – regardless of how cramped it is.
Garrets in Mansard roofs
The roof type that is most accommodating to Garrets and the people that live in them is the Mansard roof. The lower half of a Mansard’s double pitch acts as walls for the living space beneath. The lower pitch is usually fitted with windows. This allows the Garret to feel much more akin to a normal room.