The contractors, HCL, based at Alfreton in Derbyshire, have apologised for what they admit was an "embarrassing" blunder. Site manager Richard Speake told ITV News Central:
"The structure was old and unsound and basically gave way under the weight of the roof. We will be working closely with the residents to put things right and do the necessary paperwork."
Mr Speake confirmed there was asbestos in the roof, but said they had specialist staff trained to dispose of it and there was no health risk to people living nearby.
More top news
Men walked a mile long route around Worcester today in ladies' shoes to show their opposition to male violence against women and girls.
A mum who thought she could never have children was stunned after she gave birth to a baby just 2 days after finding out she was pregnant.
Rain and gusty winds will be clearing to the southeast through the evening.