Officials say the work should be done at the Bellows Falls Middle School by the time students return from the Thanksgiving holiday.
Christopher Kibbe, superintendent for the Windham Northeast Supervisory Union, said nearly 75 percent of the $10 million rehabilitation project is finished.
He said some of the priority classrooms and administrative offices should be open soon.
Much of the first floor is done, including the gymnasium and the reception area. There's also a new security system.
Work was ahead of schedule through the summer, but construction fell two weeks behind in August and caused an extended delay in the opening of school.
Administrators say they have adjusted the calendar so the students do not miss any time.