Roof Framing

• Design the roof system to support local snow and wind loads and the weight of the roofing materials that will be used.
  
• Consider designing the roof structure to support future solar thermal and photovoltaic panels. Consult an engineer to ensure that the roof design addresses loading and electrical requirements.
  
• Use raised-heel trusses or deep rafters so there is room for adequate ceiling insulation where the roof meets the wall.
  
• Provide adequate ventilation in the roof space to prevent moisture from accumulating in the attic.

Source : Canada Mortgage and Housing Corporation (CMHC)