A roof structure consists of all of the following, EXCEPT:

In a roof structure, the components typically include the rafters, sheathing, and trusses, which are all integral to the support and shape of the roof. Rafters provide angled support, trusses are engineered frameworks that distribute weight, and sheathing serves as a base to hold roofing materials and protect the interior from weather.

Ceiling tiles, on the other hand, are not part of the roof structure itself; they are a component of the building's interior finish, installed beneath the roof. They cover the underside of the roof structure and are used for aesthetics, insulation, and sound absorption within interior spaces. This distinction highlights why ceiling tiles do not belong in the classification of elements that make up the roof structure.