To obtain a building external-facing material which allows action of water absorption from a backside to be avoided or further suppressed by devising paint application to the backside of a cement base plate.

In a roofing material 1, a silane-based waterproof agent, into which emulsion paint is mixed, is applied to a downside part 9, under a state in which the base plate 2 is laid for construction as the roofing material 1, of the backside of the base plate 2 formed by making cement serve as a principal member. The ratio of mixing of the emulsion paint is set to be in a range of 10-20%.