Because different roofs require different balanced amounts of ventilation at the eaves and ridge a range of TVS is offered to suit every situation and which are simple to use when fixing flashings. Thomson Eave Ventilation Strips (TEVS) are made in two standard widths with 3mm slots either 50mm or 25mm wide and 2400mm long. Although other special sizes can be made to order.
The broad parameters for design are between 1/150 and 1/300 of the flat area of an insulated roof. Low pitched roofs and those in sheltered areas require more ventilation.The TEVS 50 has a NFA (net free area) of 17,500mm2 per lineal metre). TEVS 25 has a NFA of 9,500mm2 per lineal metre.
The Aluminium TEVS can be powder coated or have a permeable backing for marine environments. The TEVS fits into the standard groove of a fascia board while the two different sizes provide the designer with the option to balance the ventilation for the site. Aluminium soffit vents can also be used on sloping barges and apex ridges.