10 x Timloc Felt Lap Vents Roof Ventilation & Loft Condensation Attic Space 5560

Features & Benefits

• Enhances existing ventilation via felt/membrane lap joints
• Offers 3,000mm2 additional free vent area per Lap Vent
• Suitable for rafter spacings from 400-600mm centres
• Easy to install
• 2 spring clips to secure in place
• Manufactured from recycled Polypropylene
  
  

How many Lap Vents do I need?

This will vary dependent on the level of extra ventilation required and length of the roof.

To provide typical ventilation, allow for 1 lap vent every alternate rafter space at low level, on opposite sides of the roof. If maximum ventilation is required, install at high level and every rafter space along the full length of the roof.

Each lap vent provides 3,000mm2 of additional free airflow and is suitable for rafter spacings from 400-600mm centres.

It is recommended that one lap vent should be installed into every alternate rafter space at low level. If further ventilation is required, install one lap vent into every rafter space at low level or into lap joints at higher level.

The lap vents should be fitted to both sides of the roof space in order to provide cross-flow ventilation.

How to install:

1. Ensure the lap vent is orientated with clips facing inwards to the roof space and the flat surface to roof.

2. Insert the pointed edge of the lap vent into the gap between membrane/underlay overlap and then push flat towards roof line.

3. Push the lap vent down inside the joint ensuring the clips hook onto the outer face.

4. The lap vent is in the correct position when the clips are fully engaged onto the top edge of the membrane/underlay. Repeat the installation process with further lap vents until the required ventilation rate is achieved.

Please note, installing lap vents alone will not meet minimum roof ventilation requirements. For guidance and regulations on roof space ventilation please refer to British Standard BS5250.

For specifiers including the lap vent, consideration must be given to increased risk of wind uplift and driving rain resistance outlined in BS5534:2014. You acknowledge that the wind uplift loads on the tiles/slates and driving rain resistance of the membrane can be adversely affected.