St. Joseph's Hospital plans to start demolition of the DeSales Heights Academy building sometime in the next few days.
The school had its last classes in 1991, and was the site of a fire of suspicious origin in late May.
Officials at the hospital say the building was in bad shape when they bought it six years ago, but that the recent fire and on-going incidents of vandalism have made the structure a safety hazard.
"The recent fire destroyed the integrity of the building and requires us to remove the structure at this time," says hospital vice-president Sister Joan Kreyenbuhl. "Vandals and trespassers continue to destroy the building and grounds, despite securing the property."
DeSales was a Montessori school for nearly a century before its closing, and local officials have tried to save the building as a historic landmark. The hospital used part of the property for an expansion project.
Hospital officials say it should take two weeks to finish the demolition project.