LAKEWOOD — Damage to Lakewood Elementary School from a Wednesday night arson fire could exceed $200,000, and it is not clear if two classrooms can be repaired by the time school opens in September.

Insurance investigators, a structural engineer and a contractor who specializes in restoring fire-damaged buildings assessed the damage Thursday.

“The worst case right now is the two classrooms might not open when school does,” said Fred Owyen, director of operations for the Lakewood School District.

Some work will have to be done to replace trusses and plywood roof decking on the roof.

The Snohomish County fire marshal continued to investigate the fire Thursday. Fire officials said it looked like the fire was started by combustible material on the outside of the building.

The school district is fortunate to have an open classroom at the school and a portable that can be used for another classroom, Owyen said.

Owyen said the district hopes cleanup work can begin soon to keep soot from spreading and causing more damage.

At least eight good Samaritans battled the blaze before Marysville Fire District firefighters arrived Wednesday night. They broke school windows to get to fire extinguishers to fight the fire.

They included five mothers who were watching their sons’ football practice that night.

At least three men also played key roles in keeping the fire from spreading, including Art Cooper and Jim Venturo, both who live near the school, officials and witnesses said.

Cooper was one of the first to arrive after coming home from a construction job in Skykomish, said his wife, Deanna.

Fighting a fire was all part of a long day’s work for her husband, who left after firefighters arrived, she said.

“My husband is working 12 hours a day, six days a week and he just wanted to get home,” she said.

Helping out was important, however. The school has been a big part of the family’s lives. The Coopers’ daughter attended kindergarten through second grade Lakewood Elementary School two years ago.

Venturo is an Everett Fire Department investigator who lives about 100 yards from the school and rode his bike there when he saw black smoke.

He downplayed his role.

“The real heroes were those gals and those two guys and all the firemen,” he said. “All I did was direct them to where the fire was and I checked the interior of the school.”

Venturo said the fire damage points to the need for sprinklers on the outside of some buildings. Exterior sprinklers would have limited the damage, he said.

“It would be a good idea in the future,” he said. “Ideally, it would be great to have sprinklers underneath the eaves.”

There will be up to a $10,000 reward offered through the Arson Alarm Foundation for information on Wednesday night’s fire at Lakewood Elementary. Call 800-55-ARSON.

Reporter Eric Stevick: 425-339-3446 or stevick@heraldnet.com.