Lap Vent

• Discrete profile design
• Easy installation
• 2 spring clips to secure each unit in place

• Manufactured to British Standards: BS EN 9001 and BS EN 14001

• Injection Moulded recycled Polypropylene
• Off-white

• 3000mm2 additional free vent area per unit.
• Suitable for rafter spacings from 400-600mm centres.
• Designed only to enhance existing ventilation via felt/membrane
  lap joints.
• Consideration must be given to increased risk of wind uplift and
  driving rain resistance outlined in BS5534:2014.

• Allowing ventilation between roofing felt/membranes is secondary to eaves and/or ridge ventilation
• Lap vent simply slots between roof felt/membranes laps
• Position the lap vent clips facing down to hang on the edge of the roofing felt/membrane when in postition
• Install one lap vent into every alternate rafter space at low level
• If further ventilation is required, install one lap vent into every rafter space at low level and/or into lap joints at higher levels
• The lap vents should be fitted to both sides of the roof space in order to provide cross-flow ventilation
• Installing lap vents alone will not meet m minimum roof ventilation requirements. For guidance and regulations on roof space ventilation please refer to British Standard BS5250

N.B. By specifying the lap vent, you acknowledge that the wind uplift loads on the tiles/slates and driving rain resistance of the membrane can be adversely affected

• Calculate quantity of lap vents based on the level of ventilation required
• For typical installation allow 1 lap vent per alternate rafter spacing at low level
• Increase ventilation by allowing additional lap vents at high level
• For maximum ventilation allow lap vents to every rafter spacing