The owner of an old bingo hall set the building on fire after a dispute with the man who was renting it.
Paul Bell, 49, caused a "massive blaze" that destroyed the entire building in Sunderland, which he'd bought in 2016 for £105,000.
When the fire broke out, it was being rented by another man, who ran it as an auction house and furniture shop, Newcastle Crown Court heard.
The two men had had a dispute sometime before.
Thirteen fire engines attended the blaze, which happened in February 2017, and firefighters from Gosforth, in Newcastle and Seaham, in County Durham had to be drafted in to help.
One firefighter who entered the building while it was burning said visibility inside was just "black fog" and water had no effect on the flames.
The emergency crews eventually had to leave when the roof of the property started to collapse, reports Chronicle Live.
Photographs taken in the aftermath of the fire show the building was "completely destroyed". Prosecutor Andrew Espley told the court: "We don't say Mr Bell intended as much damage as was caused.
"His intention was maybe to destroy the property belonging to the tenant."
Mr Espley said the fire had a "significant impact" on the emergency services and described it as a "massive blaze".
The court heard the tenant, who had no contents insurance, lost £10,000 worth of property and said in a victim statement: "My life was changed forever going forward.
"Not only did I lose what I worked so hard to build, myself, staff and our community lost their jobs and belongings. I paid customers compensation out of my savings." He said he was even accused of starting the fire himself and was subjected to accusations and online trolling.
Bell, of Coxhoe, Durham, admitted arson and has been jailed for 21 months. Judge Robert Spragg said: "Firefighters called to large fires such as this are always in danger. There must be an element of deterrence.
"In my judgement, deliberate setting of a fire in circumstances such as this, leading to massive damage and attendance of fire officers who attend buildings at great personal risk, means appropriate punishment can only be achieved by immediate custody."
Bell's "henchman", Terry McEwen, who did work for him, was there when the fire was started and drove Bell away from the scene, and admitted assisting an offender.
McEwen, 51, of Lydia House, Market Place, Hexham, Northumberland, was sentenced to nine months, suspended for 12 months, with 80 hours unpaid work.
Judge Spragg said McEwen had acted "under instruction" and added: "Clearly the offence would not have happened if it had not been driven by Mr Bell."
Susannah Proctor, defending, said Bell was using cocaine at the time but has not taken illegal substances since. Miss Proctor added: "He has lived his life as a hard-working man, working in various businesses, running successful businesses for a number of years."
Defending McEwen, Adam Birkby said his client is a hard worker who is in good employment that takes him around the country.
