Tile with a substantially flat structure, notably intended for laying on a shallowly sloped roof, comprising an inner surface intended to be laid facing a roof having a slope and an outer surface opposite to the inner surface, the outer surface having: - a planar gauge intended to directly receive the rainwater, - an upper interlocking portion located in the continuation of the gauge in a longitudinal direction corresponding to the line of steepest slope of the roof, the upper interlocking portion being configured to be overlapped by an adjacent tile in the longitudinal direction, - an outer lateral interlocking portion located at a lateral rim of the gauge, the outer lateral interlocking portion being configured to be overlapped by an adjacent tile in a transverse direction of the roof, the transverse direction being orthogonal to the longitudinal direction, wherein the inner surface has an inner lateral interlocking portion comprising at least one rib (11, 12, 13) extending in the longitudinal direction, and wherein the outer lateral interlocking portion comprises at least one groove (8, 9, 10) extending in the longitudinal direction, the at least one groove (8, 9, 10) being configured to receive one of the at least one rib (11, 12, 13) of the inner lateral interlocking portion of an adjacent tile in the transverse direction, a bottom wall of the at least one groove (8, 9, 10) comprising a staircase-shaped portion extending over at least part of the dimension of the groove (8, 9, 10) in the longitudinal direction and over the entire dimension of the groove (8, 9, 10) in the transverse direction, the staircase-shaped portion having at least one surface of a riser facing a lower longitudinal end of the tile to act as an obstacle to rainwater rising in the groove (8, 9, 10). the outer surface having: - a planar gauge intended to directly receive the rainwater, - an upper interlocking portion located in the continuation of the gauge in a longitudinal direction corresponding to the line of steepest slope of the roof, the upper interlocking portion being configured to be overlapped by an adjacent tile in the longitudinal direction, - an outer lateral interlocking portion located at a lateral rim of the gauge, the outer lateral interlocking portion being configured to be overlapped by an adjacent tile in a transverse direction of the roof, the transverse direction being orthogonal to the longitudinal direction, - a planar gauge intended to directly receive the rainwater, - an upper interlocking portion located in the continuation of the gauge in a longitudinal direction corresponding to the line of steepest slope of the roof, the upper interlocking portion being configured to be overlapped by an adjacent tile in the longitudinal direction, - an outer lateral interlocking portion located at a lateral rim of the gauge, the outer lateral interlocking portion being configured to be overlapped by an adjacent tile in a transverse direction of the roof, the transverse direction being orthogonal to the longitudinal direction, wherein the inner surface has an inner lateral interlocking portion comprising at least one rib (11, 12, 13) extending in the longitudinal direction, and wherein the outer lateral interlocking portion comprises at least one groove (8, 9, 10) extending in the longitudinal direction, the at least one groove (8, 9, 10) being configured to receive one of the at least one rib (11, 12, 13) of the inner lateral interlocking portion of an adjacent tile in the transverse direction, a bottom wall of the at least one groove (8, 9, 10) comprising a staircase-shaped portion extending over at least part of the dimension of the groove (8, 9, 10) in the longitudinal direction and over the entire dimension of the groove (8, 9, 10) in the transverse direction, the staircase-shaped portion having at least one surface of a riser facing a lower longitudinal end of the tile to act as an obstacle to rainwater rising in the groove (8, 9, 10).