Armatool 30m Longo Chalk Line 
Manthorpe Felt Lap Vent is a refurbishment product designed to increase the amount of ventilation into existing roof spaces. Furthermore, Manthorpe Felt Lap Vent is usually fitted retrospectively to properties with additional loft insulation recently installed. To add, Felt Lap Vent helps to combat the problem of condensation builds up in any roof space with a lapped felt/membrane construction.
The specifier should ensure that the opening of felt laps on the property will not adversely increase the wind uplift load on the tiles/slates or the driving rain resistance of the roof
