NORWOOD PARK — Work began Wednesday on a massive construction project at Taft High School in an effort to repair the nearly 75-year-old building, the most crowded high school in the city.

Students and parents no longer have access to any of the parking lots at the school, 6530 W. Bryn Mawr Ave., because of three large construction zones around the school.

A message from school officials urged parents to drop students off on the curb along Natoma Avenue, on the west side of the school, or along Bryn Mawr Avenue. School begins at 7:45 a.m. with the last classes ending at 3:03 p.m.

The $17 million project will overhaul the school's nine science labs, patch crumbling brick, repair water damage and replace the school's lockers, officials said. The work will reverse decades of neglect, school supporters said.

Only Taft staff members, with proper identification, will be allowed to park in the school's lots, officials said.

In addition, many of the school's windows — so clouded with age that students can't see out of them — will be replaced. The project is expected to last through this school year and into the summer.

Acting Principal Carolyn Rownd said construction would start in earnest later this month, but said school officials wanted students and parents to get used to the parking lot closures as soon as possible.

A spokesman for the Chicago Public Schools district said the project was designed to "catch up" with "delayed or deferred" maintenance at Taft.

Taft's utilization rate is 146 percent, with 3,195 students attending class in a building with an ideal capacity of 2,184 students, making it the most crowded Chicago Public Schools high school, according to data released by the district.