Almost all tools and equipment used by a mental health charity have been destroyed in a suspected arson attack.
Firefighters were called to the headquarters of Men in Sheds in Oak Road, Hull at about 05:00 GMT.
Baz Wharf, from the organisation, which helps men feeling lonely and isolated by teaching them woodwork, said the damage was "astronomical".
It means the charity will not be able to complete a number of projects that members were working on.
Chairman Mr Wharf said: "The unit was full to the rafters with good quality wood, which won't be easy to replace.
"Most of the materials have all gone. What isn't damaged from the fire has been water damaged by the fire brigade.
"It's a total write-off in there."
Councillor Dave McCobb said the charity had become a "really popular addition to the local community".
He added: "If it is the case that this was arson, then it's shocking and disgraceful that someone would deliberately damage a facility for a group that was set up to help the local community."
The charity is appealing for donations to replace the damaged items.
Humberside Police and the fire service are investigating.