Removal is slow, manual work. There is no machine that lifts foam off in sheets.
The process
Dust sheets go down, the crew wear respirators, and the foam is cut and scraped from tiles, battens and rafters in sections. It is bagged and taken away.
Afterwards
Timbers are inspected once they are clear. Damaged battens, felt or slates may need replacing, and the roof can then be re-insulated in a way lenders accept more readily.
Related: Spray foam removal