ROOF BACKING MATERIAL

PROBLEM TO BE SOLVED: To shorten a construction work by previously providing dewatering material in the direction of an eaves ridge on the joint parts of roof tiles so as to correspond to the width of a roof tile being roofed on a roof backing material main body. SOLUTION: Dewatering materials 2 are previously formed on joint parts of roof tiles so as to correspond to the width of a roof tile being roofed on a roof backing material main body 1 laid on a roof panel, a roof surface, or the like. The dewatering material 2 is provided with a pair of or a plurality of pairs of ribs 6 facing to the center part of the joint or from the center parts of the joint to the right and left so as to form drain passages. Further, the eaves side end part of the dewatering material 2 is formed into a lapping tolerance 3 a little projecting from the roof backing material main body 1, and lateral guide lines 4 are on the roof backing material main body 1 and longitudinal guide lines 5 are on the dewatering material 2, respectively formed. Consequently, the roofing positions of the roof tiles can be easily decided, and invading rain water can easily flow down.