In the Palermo Cathedral, the dromic roof was above the rafters in the nave. It was an serviceable roof with a central wooden walkway: a plank from which it was possible to walk through the entire nave. This system is still present in the roof of the Cefalù Cathedral.
The 18th century restoration work, devised by Ferdinando Fuga and then partly carried out by Marvuglia, altered much of the ceiling. The roof of the nave was reduced from 19 trusses to 15. A transept was inserted and the old, formerly exposed roof, crossed by the dromic roof, was then reworked and concealed by the barrel vault covering the nave of the church.