BBC News By Felicity Hannah Leaseholders have warned about the potential dangers of adding rooftop developments to blocks of flats. It follows a change in the law which makes it easier for freeholders to build up to two extra storeys on top of their buildings. Some flat owners have said their homes have been left damaged and devalued by new developments. The government said such developments would help meet the demand for new homes. 'Badly damaged' Residents at Apex Court in West Ealing, London, said the building had experienced extensive flooding, cracks and even falling cladding since a f...