Hi, I would say that in general if its major demolition/construction work then occupants should not remain in the building. However if part of the building has to remain occupied during the demolition/construction of another part of the building then it must be down to risk assessment. You will need to consider amongst other things the nature of the premises, who will be exposed, extent and nature of the work, risks to the occupants, time to complete the work, provision of evacuation of occupants etc. etc. Protecting the Public HSG151 has this info for work in occupied premises, see the following link: http://www.hse.gov.uk/pubns/priced/hsg151.pdf Also there is the Code of Practice for Demolition BS 6187. Regards Steve