Aaron Foster was a teenager when he caused £180,000 worth of damage to the library when it was set alight in August 2020.
On the evening of February 1 this year the then 19-year-old also started a blaze which engulfed the Ash Green primary school in Mixenden.
Foster, of Stanningley Drive, Mixenden, had denied both arson charges, but a jury at Bradford Crown Court returned unanimous guilty verdicts at the end of his trial today.
The jury had heard evidence from a woman who said that she had seen Foster smash a window at the library and climb in minutes before she saw flames flickering inside.
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She told the court that after the alarms went off Foster came out and followed her back to nearby garden where she said he was “laughing about what he had accomplished”.
The witness described how Foster had said he was after money in the library, but there wasn’t any and he had set the fire to get rid of his fingerprints.
During the trial the jury was also shown CCTV footage of Foster breaking into Ash Green primary school on the evening of the blaze.
Foster was captured on CCTV walking around the school using the torch function on his mobile phone and carrying a lit cigarette.
A subsequent fire investigation suggested that there had been three or four seats of fire.
Prosecutor Camille Morland said the footage showed Foster going into classrooms in the Key Stage Two area and captured the moment the first fire was started.
The jury was told by Miss Morland in her opening address last Wednesday that at one point Foster himself phoned the emergency services claiming to be “trapped” in the burning school building and the recording of the call was played to the jury.
During the call Foster claimed his mates had suggested stealing the school iPads to get some money.
He claimed his mates had ditched him and the flames were all around him.
“All I can see is flames,” he told the control room operator.
“I’m in a hallway. All I can see is flames.”
During cross-examination by Miss Morland Foster was accused of “playing the victim” after he went back into the already burning building and made the 999 call.
After being rescued from the building he denied starting the fires claiming others were responsible.
Foster was remanded back into custody after the guilty verdicts were returned and Recorder Simon Myerson QC said fixed his sentence hearing for October 12.