Manthorpe G630 Roof Felt Lap Ventilator - 3,000mm²/m Airflow

Manthorpe G630 Roof Felt Lap Ventilator - 3,000mm²/m Airflow is a roof felt / underlay ventilator designed to improve loft airflow, helping reduce condensation and prevent moisture build-up behind the roof covering.

It is fitted from inside the loft by separating the laps in the underlay at underlay or felt-lap level. Rather than replacing a roof tile or slate, it creates a discreet ventilation path through the roofing membrane so stale, humid air can escape from the loft void.

Best for

• Loft condensation issues in existing pitched roofs
• Improving airflow at loft level without a visible roof tile vent
• Supplementary ventilation alongside existing eaves, soffit or ridge ventilation

Key features

• Helps reduce condensation and trapped moisture in the roof space
• Improves airflow through the loft void
• Prevents moisture build-up behind roofing underlay
• Does not connect to extractor fans or soil pipes

Compatible with / used with

• Used with lapped roofing felt or membrane systems
• Works independently of slate, concrete tile or clay tile profile because it vents at underlay/felt level
• Can support eaves/soffit/ridge ventilation strategies
• Not designed for connection to pipes, adaptors, extractor fans or soil ventilation

Ventilation performance

• approximately 3,000mm²/m airflow equivalent where stated in product data
• Spacing/quantity should be assessed across both roof slopes for effective cross-flow

Things to consider before buying

• Check the roof has suitable felt or membrane laps before buying
• Investigate and reduce moisture sources inside the home as well as adding ventilation
• Do not block eaves ventilation with insulation
• For powered extraction from bathrooms/kitchens, use a dedicated tile vent/adaptor/flexipipe system instead