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715 LAYING REINFORCED BITUMEN MEMBRANE ON ROOFS PITCHED MORE THAN 5°
• Timber battens: Fix flush with surface in substrates that will not securely accept nails.
- Locations: To BS 8217, table 5.
- Size: 50 mm wide x thickness of insulation.
• Setting out: Parallel to roof slope, with successive layers carried over ridges.
- Lengths (maximum): As recommended by bitumen membrane manufacturer.
- End laps: Half stagger and align on alternate bitumen membranes.
• Additional fixing of bitumen membranes: As recommended by bitumen membrane
manufacturer.

720 NAILING FIRST LAYER OF REINFORCED BITUMEN MEMBRANE TO TIMBER SUBSTRATE
• Setting out: Unroll, align and cut to length and work from one end. Minimize
wrinkles.
• Fixing centres:
- General area: Maximum 150 mm grid centres.
- Perimeter of roof areas and at all side and head laps: 50 mm.

735 POUR AND ROLL BONDING OF REINFORCED BITUMEN MEMBRANE
• Bonding compound:
- Hot and fluid when bitumen membranes are laid.
- Application: Spread evenly so that a small quantity is squeezed out at each
edge.
• Bond: Full over whole surface, with no air pockets.
• Excess compound at laps:
- First and intermediate layers. Spread out.
- Top layer/ Capsheet: Remove.

745 COLD APPLIED ADHESIVE BONDING OF REINFORCED BITUMEN MEMBRANES
• Bond: Full over whole surface, with no air pockets.

747 SELF-ADHESIVE BONDING OF REINFORCED BITUMEN MEMBRANES
• Bond: Full over whole surface, with no air pockets.

750 LAYING MINERAL FACED REINFORCED BITUMEN MEMBRANES
• Lap positions and detailing of ridges, eaves, verges, hips, abutments, etc: Submit
proposals.
• Setting out: Neat, with carefully formed junctions.
• Lap bonding: Carry out only at prefinished margins or prepared 'black to black'
edges.
• Excess bonding compound at laps: Remove whilst still warm.

755 LAYING METAL FACED REINFORCED BITUMEN MEMBRANES
• Lap positions and detailing of ridges, eaves, verges, hips, abutments, etc: Submit
proposals.
• Setting out: Neat with carefully formed junctions.
• Excess bonding compound at laps: Remove whilst still warm.
• Metal face: Do not mark, crease or stain.

RotF generic (intermediate) NBS 2014 6118-AEW-XX-XX-NBS-A-01