September 10, 2018 Home page » Implementation instructions » Rules for laying of weldable membranes » Rules for ventilation of the roofing membrane Principles of laying the weldable roofing papers Basic implementing rules Equipment and tools Substrate preparation Paper laying methods Principles of making coverings on new roofs Principles of renovation of roofing materials Principles of ventilation of the roofing felt Health and safety and fire regulations Rules for laying roofing shingles Rules for the use of asphalt masses Online shop INSULATION - JAROCIN SA ul. Poznańska 24-26 63-200 Jarocin tel. (+48 62) 747 04 00 fax (+48 62) 747 04 04 e-mail: biuro@izolacja-jarocin.pl PRINCIPLES OF VENTILATION OF THE ROOFING FELT When making new roof coverings and renovating roofs on non-ventilated flat roofs, due to the high diffusion resistance of heat-welded roofing membranes, it is very often necessary to ventilate the roofing. Effective deaeration is ensured by the use of perforated ventilation tar paper and ventilation chimneys. Such a system allows the removal of moisture that collects under the cover to the outside. In order to ensure effective venting, it is recommended to use one ventilation chimney for an area of 40 - 60 m². The ventilation felt is laid without gluing on a dry, primed concrete surface or old roofing felt. The stripes of ventilation tar paper are laid without the use of overlaps. In order to allow effective drainage of moisture, the surface of the old roofing felt should be unsealed to the damp layer, e.g. by making holes with a drill or cutting the old substrate. The next layer of tar paper is welded to the substrate through holes in the ventilation paper. The ventilation tarpaulin should not be placed in places particularly exposed to water ingress under the roofing, i.e. in the eaves strip, at roof outlets and drainage channels, at the building's structural expansion joints, at chimneys and firewalls, etc. In these places, the tar paper is moved away by a distance of 50 cm . Ventilation (perforated) tarpaulin is not included in the number of cover layers. 2018 © IZOLACJA-JAROCIN SA Site map