"Happy Thanksgiving" is still scribbled across the chalkboard in an abandoned classroom attached to Farrington High School’s auditorium, steps away from where the facility’s roof collapsed 16 months ago.

The day after Thanksgiving in 2012, a 40-foot section of roof on the 58-year-old auditorium crumbled during a brief but intense thunderstorm that battered Oahu with heavy rain. One person was inside but was not hurt.

After conducting an investigation and completing design work in the months since the accident, the Department of Education is soliciting bids for the construction phase of a $12 million makeover that will essentially gut the space that once hosted school assemblies and theater performances for the state’s fourth-largest high school.

The department expects to award a contract next month, and work is set to begin at the end of summer.

"We’re really excited to get it back," said Principal Alfredo Carganilla. "Performing in the gym or the cafeteria is just not the same as performing on a stage."

The collapse left a gaping hole that stretches the entire width of the auditorium’s roof. Most of the facility’s 1,100 seats were destroyed, and the months-long exposure to the elements has since damaged everything from lighting and sound equipment to projector screens, flooring and wall coverings.

The DOE on Thursday allowed reporters to see inside the building before closing it off as an active construction site. The renovation is expected to take nine to 12 months.

"It’s going to look like a brand-new building inside," said DOE spokeswoman Donalyn Dela Cruz. The exterior shell will not be altered.

"This was built in the ’50s, and here we have an opportunity to build for today’s needs while also looking at what this can grow into," Dela Cruz said.

Honolulu-based Yamasato Fujiwara Higa & Associates was awarded a contract for the design phase of the project.

Carganilla said the school was involved in the design process and lobbied for added seating capacity, dressing rooms, office space and an area to house the school’s media and technology program, among other needs.

"Our students, alumni, the community are all eager to use it again," said Vice Principal Ronald Oyama.

New Hope Christian Fellowship, which had been renting the auditorium for services since 1994, now holds its services at the New Hope Ministry Center on Sand Island Access Road. The church had paid to refurbish the auditorium’s seating a few months before the roof gave out.

A DOE investigation found the roof collapse was due to a design failure dating to the building’s original construction in 1956. The culprit was a center steel roof truss whose "design limit" was overextended by an attached 9-foot concrete walkway that provided access to lighting and sound equipment.

"The design was inadequate from the get-go," said Duane Kashiwai, public works administrator for the DOE’s facilities branch.

The DOE has since inspected similar auditoriums, gyms and other buildings constructed around the same time as Farrington’s at a dozen other schools statewide, which have been deemed safe.

Dela Cruz said funding for the project will come from a combination of sources, including insurance, state risk management funds and DOE repair and maintenance funds.