Mark Hall, 28, and Thomas Richardson, 27, both from Pipers Close, Haverhill were jailed for burning down Chilford Hall in Linton last summer
Richardson had worked at Chilford Hall but was sacked in 2009 after drinking at work and stealing vodka.
He repeatedly threatened to burn down the hall following his dismissal and challenged general manager and director Geln Mejias to a fight.
He was cautioned for making these threats in 2009.
Hall, who has autism, was adopted aged seven and moved to Haverhill at 17.
He did not work and began drinking heavily following the death of his adopted father last April.
He said he felt indebted to Richardson after he broke his laptop by spilling cider on it.
The pair had been drinking heavily on the night before fire was started in the barn – they said they went there to break in and steal booze.
Hall said Richardson initiated the fire by pouring alcohol on the barn floor and lighting it, though Richardson stated Hall began the blaze by setting alight paper napkins in a bin under tables.
Police were alerted after receiving a call from Sally Ketteridge, who Richardson lived with, saying they had threatened to burn down Chilford Hall and were in a black Honda.
Up to ten fire crews and 60 firefighters responded to reports of smoke coming out of the baren at 3.19am, and by 5,20am the barn had burnt down, though firefighters had stopped the blaze from spreading throughout the site.
Officers spotted the car driving out of the grounds towards Linton, and the pair were later arrested in Haverhill, with Hall found outside in Pipers Close and Richardson inside in just his underwear.
Bin bags containing empty spirit bottles and white tissues soaked in alcohol were found inside the car, and investigations at the scene confirmed the inferno had been started deliberately.
For all the latest news see Thursday’s (February 21) Echo,