Montclair High School will be closed for at least one additional day following last week's stairwell collapse.

District officials made the decision to close the school on Tuesday to allow building inspectors and architects to examine all of the staircases in the two school buildings used by high school students and staff.

At about 5 p.m. today school officials announced they would also be closed Wednesday, Sept. 12, to further assess the facilities.

The school is expected to reopen with a two-hour delay on Thursday, Sept. 13, according to an email by Superintendent Kendra Johnson sent to parents Tuesday afternoon.

"The Annex was cleared for full use, and select areas in the main building were also cleared. Regrettably, we will not have full access to the main building, and therefore, we will close Montclair High School again tomorrow for one final inspection," Johnson wrote.

Both the George Inness Annex and the main building will remain closed to all students, staff and visitors, except for authorized district staff, architects and outside consultants.

No one was injured when the stairwell partially collapsed on the morning of Sept. 7. Staff closed off the stairwell and re-routed foot traffic to the remaining four staircases in the building.

Staff will report to school at their regular time on Thursday. First period classes for students will begin at 10 a.m., and there will be no zero-period classes.

A photo shared on social media, and on a local news site, showed what appeared to be the damaged staircase. The photo showed six steps near the top of the staircase buckled inward and starting to pull away from the wall.

The district architect and the director of buildings and grounds are expected to present a report on the stairwell damage at the next board of education meeting on Monday, Sept. 17 at 7:45 p.m.