Features and benefits: • Efficient, very unobtrusive and easy to fit • Superior strength construction - will carry the weight of the bottom row of tiles • 3.5mm - 4mm wide ventilation slots comply with BS 5250 : 2011 • Durable and totally resistant to decay • UV stabilised and colourfast • Supplied in convenient 1m lengths The Over Fascia Vent is used where the fascia board is fitted in the ends of the rafters, so creating a situation where ventilation can only be effected over the top of the board. OF1 provides ventilation equivalent to a continuous 10mm opening (10,000mm²) and is used to ventilate pitched roofs of 15°> and the roof void is uninhabited loft or attic space.