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.
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Monday will see another fine and dry day after a cloudier start for some.
Low cloud will gradually become confined to the coast allowing sunny spells in the afternoon.
Into the evening it will remain dry with the best of the clear spells in the west.