A loft is the volume enclose by the roof structure. When there is a large amount of space under the roof and the structure is created using collar-beam trusses which open the space, it is easily convertible.
Inversely, industrial flat trusses are formed by assembled triangulations which close off all the inner volume. To convert them into living spaces, a major and highly technical transformation must be performed.
Collar-beam trusses © www.charpentes-latapie.com
A roof structure with industrial flat trusses. © www.siga-charpente.com