"We're getting over the shock right now," said Farrington High School Principal Al Carganilla.
Structural engineers were welding and mounting steel pipes on the outside of the building to reinforce it on Monday.
Carganilla said there's still an uncovered, gaping hole where a 40-foot section of the roof dropped to the floor.
"It could be combination of things, I think the wear and tear and age is part of it," he said.
A flash storm dumped rain on the area shortly before the roof collapsed at about 3:15 Friday afternoon.
Carganilla said the auditorium is 58 years old.
Assistant Superintendent Ray L'Heureux told KITV the roof was built in 1985 and fixed in 1992.
He said the department is also in the process of streamlining its procurement process to get to construction projects faster.
He said the department has also been updating its maintenance trouble shooting call system.