Harrison denied lighting the fire.
The first two attempts at a jury trial were abandoned — one after the foreman of the jury quit on the first day, the second after a Fire Service witness failed to disclose evidence — while the judge-alone trial was slowed by a Covid-related case backlog and the sheer volume of technical evidence.
He was found guilty of two counts of arson by Judge John McDonald in March this year.
Prosecutor Shannon-Leigh Litt called for a jail term of 3.5 to 4.5 years.
While Harrison had not made a claim on insurance the damage caused was extensive and firefighters were put at real risk, she said.
Defence lawyer Michael Dodds called for a sentence of community detention.
The only people who had suffered loss, and a serious loss at that, were Harrison and his wife.
He also asked the judge to consider Harrison's mental state at the time of the fire and his support over many years for community events.
"He was under a lot of stress, not financial stress, but work stress. His mother had just died. He had to put off her funeral due to work commitments. He has suffered from anxiety his whole life ... This is a man who has, over a 40-year period, been a stalwart to his community and generous to a fault."
The large turnout in court was evidence of the esteem in which he was held.
The fact the case had been hanging over Harrison's head for five years should also be taken into account, Dodds said.
Judge McDonald said he accepted premeditation was lacking and that Harrison was under extreme emotional stress at the time.
He had a job that was emotionally and physically demanding, his mother had passed away, he wanted more time with his daughter, he was "staring down the barrel" of a busy festival season, and his wife had to go to Malaysia to look after her ailing mother.
"In the heat of the moment ... you decided the only way out for you was to destroy your own business. I also found that you quickly regretted what you had done, as often happens when someone does something in the heat of the moment and the height of despair ... But the deed is done."
Judge McDonald said he did not accept the theory put forward by the defence that the fire was caused by spontaneous combustion of linseed oil rags.
While no one was in the shed at the time a large number of volunteer firefighters attended. Those that entered the building first were in real danger, he said.
Thirty-six people submitted character references, all of whom spoke highly of Harrison and his service to the community.
Many writers were critical of the court's guilty verdict but very few had actually attended the hearings, he said.
Judge McDonald reduced the starting sentence by 15 per cent for previous good character and took off nine months for the serious impact of the delays.
He could not offer a discount for remorse because Harrison did not accept the verdict, as was his right.
The end sentence of 10 months' home detention was greeted with loud applause from his supporters.
No order for reparation was made because Harrison owned the destroyed property and Fire and Emergency NZ did not seek costs.
