North Yorkshire Fire and Rescue Service and North Yorkshire Police are investigating after being called to the incident on Whitcliffe Lane at 8am on Monday.
A NYFRS spokesperson said: “The fire involved floorboards and joists and caused fire, heat and smoke damage to the room of origin, with some smoke damage to the rest of the building.”
New Harrogate cyclepath: key public meeting Neighbourhood Policing for Ripon, Pete Macmillan, said the fire is being treated as arson due to the scale of the damage.
The fire was extinguished using two hose reel jets, eight breathing apparatus, two thermal imaging cameras, three saws, two hooligan tools and two triple extension ladders.
Firefighters were on the scene for more than two and a half hours.
This is not the first time that the choir school building has been targeted by arsonists - in April last year, another fire caused damage to one of the classrooms, which prompted wider concerns about the vulnerability of empty historic buildings in the city.
Police called to report of sudden death in Ripon - air ambulance sighted by residents Reacting to the news of the fire this week, the Chairman of Ripon Civic Society, Chris Hughes, said: “Ripon Civic Society will do what it can to keep historic buildings at risk under scrutiny and will press for action where neglect is likely to turn into damage and ultimate loss.
“2019 is the fiftieth anniversary of the designation of Ripon Conservation Area, and Ripon Civic Society will be recalling building restoration successes. We shall also be pointing out the risks to our built heritage and the opportunities that conservation can bring to Ripon’s vitality.”
Vote for your favourite Yorkshire landmarks in BBC Countryfile Awards as shortlist is announcedAnyone who has any information about the fire should call 101, quoting log 80.
The Civic Society has also previously raised concerns about the future of Ripon’s Old Lecture Block and former girls’ high school on College Road, and lobbied Harrogate Borough Council and developers to protect it from any deterioration and vandalism.