For complex structures this would typically be an 'Advanced Scaffolder' or an individual that has received training in a certain sort of system scaffold for the intricacy of the arrangement involved. http://www.diywiki.org/index.php/Scaffolding_And_Gain_Access_To_Solutions_In_The_South_East_Including_Hastings_Bexhill_Eastboune_From_Influence_Scaffolding_Guild_Of_Master_Artisans_Signed_Up