System selection: Bituminous multi-purpose underlay

• 1.Wood framing
• 2.Rafter
• 3.Insulation board
• 4.Vented space
• 5.Underlay membrane FEL'X MULTI
• 6.Tiles or Slates
• 7.Roof battens
• 8.Battens
• 9.Vented space