The weekend fire that destroyed the 19th century building housing Wyncote Academy evidently was set, the Cheltenham Township fire marshal said Monday.

"The concept that someone would deliberately set fire to a building that caters to students, and especially those with special needs, it's actually horrifying," said Kerry Leraris, head of the school on Washington Lane.

Officials offered few details as investigators continued to sort through the building's remains, and the faculty scrambled to set up leased classrooms at Gratz College.

Fire Marshal Joseph W. O'Neill said most of the building's slate roof burned off and its second floor collapsed in the fire. On Monday afternoon, he was awaiting the arrival of heavy machinery to help the investigation.

O'Neill said he had not yet determined where the fire began. "We want to get it right," he said.

Parts of the building's stone walls were still standing Monday, and its first-story doors and windows were covered with boards. The private school for students in sixth through 12th grades opened in 1983 in the old manor house, built in the 1870s.

Firefighters received the call about 6:30 a.m. Saturday, said La Mott Fire Company Chief John Mulligan. They located the scene about 20 minutes later, and found heavy smoke and fire coming from the building.

A few miles away Monday afternoon, Wyncote's teachers were working to move into Gratz, where the school has leased a corridor of classrooms.

Leraris contacted a textbook company while teachers moved furniture and went shopping for supplies. Local school districts agreed to lend sports equipment. Other groups have offered donations, and plans for an April 25 benefit auction event were underway.

"We have nothing," Leraris said. "I don't even have pencils."

Wyncote has about 65 students who have not excelled in traditional school environments due to learning disabilities and social skill or other issues, Leraris said.

She said students who heard about the fire immediately asked, "When can we come back to school?"

Outside the school Monday morning, music teacher John Poole said he was worried about the equipment in his classroom, which included a recording booth. He said he had heard that the music room was largely spared, but was not able to enter the building to see it.

To fill the temporary music classroom, "I'm going to bring a lot of stuff from home," Poole said.

The fire scene was surrounded by a chain-link fence Monday and guarded by Cheltenham Township police.

The investigation involves Cheltenham and state police and Montgomery County detectives.

lmccrystal@phillynews.com

610-313-8116 @Lmccrystal