Abstract: A roofing plate (10), such as a corrugated, interlocking tile, is at its upper side surface provided with a proofing strip (27) arranged extending across the corrugations of the roofing plate at the upper edge thereof. The proofing strip (27) is constituted by a strip of upright synthetic fibres, such as a combination of polyamide fibres of a length of 3 mm and of a length of 5 mm and of thickness of 0.05 mm (22 dtex). The strip (27) is adapted to provide a barrier when its is clamped between the upper side surface of the roofing plate and the lower side surface of an adjacent roofing plate, and the barrier permits the passage of air from the inside of a loft defined below the roofing plates and out and form the outside and into the loft and further permits the passage of water from the inside of the loft and out, and blocks the passage of water and dust form the outside and into the loft.