Lawmakers and education leaders toured the $11.9 million renovation project after a blessing on Tuesday.
State Department of Education assistant Superintendent Dann Carlson said while he would have liked the work to be wrapped up sooner, "four year ... from basically getting caught flat-footed to a completion of four years is actually a great accomplishment."
Students got their first glimpse inside the auditorium last month for homecoming and other activities. None of them attended the school in November 2012, when a 40-foot section of the roof came crashing down during a rainstorm.
"The first thing that I said when I entered the auditorium was, 'Wow!' Everything was so nice," said John Brian Babad, a junior at the school.
Engineers said a structural flaw contributed to the collapse.
Farrington Principal Al Carganilla said the finished product was worth the wait.
"We had to be really patient. I think our community had to be patient. There was delays along the way, but it was good delays, only making sure that we do it the right way," he said.
The renovated auditorium includes new classroom space and other improvements.
"Our journalism and our drama classes are held in here. We have our new dressing rooms upstairs and just our media center up there with the sound, it's state of the art," Carganilla said.
Community groups that also rented the building before the collapse are already lining up to get back in again.
"The bringing back of the auditorium gives us and the rest of the students a sense of pride, but not only to us, but the community as well since it's able to be an up and running facility," said junior Sherimae Murro.
The first community event in the auditorium will be a benefit show put on by Augie T on November 19. The money raised will be donated to the school.