Faizal, who did not want to give his surname, said the fire service had now deemed the building unsafe.
As the site was used to create wooden units, the business will have to close for “the time being”, he added.
“There’s nothing else we can do now,” he said. “We’re going to have to cancel the jobs that we have.
“We’re just going to have to see how it is, have a chat with the landlord to see what he wants to do with the building, and then we’ll have to take it from there.
“It’s life – we’re all family around here and we’re all supportive of each other, so it’ll be OK.”
Leicestershire Fire and Rescue Service has been contacted regarding the cause of the blaze, which has not yet been determined.