Answer to Question 2:

Hi Michael:

In short, yes, as a minimum, some form of sheeting would be recommended in places where you cannot prevent access to the danger areas either by restricting access to adjacent entrance or by providing a covered walkway.  Sheeting may consist of netting, corrugated sheets or timber sheets.  It should be fixed securely to prevent materials from passing through.  Sheeting should be inspected regularly, particularly after strong winds. Keep in mind that sheeting will significantly increase the wind loading on a scaffold, the ties and tie couplers. 

The HSE (UK) and HSA (Ireland) advise particular care is needed where there is public access close to roof work.  Try to arrange for work to be carried out when passers-by will not be there.  If this cannot be arranged use physical protection to catch falling materials but remember that even fine material such as dust can cause discomfort or injury to eyes.

Kind Regards,
Paul