Up and over single panel garage door flood proofing apparatus comprising: a u-shaped first interlocking gasket for mounting on an inner surface of the garage door, to extend in a u-shape around a periphery of a lower portion of said inner surface; a u-shaped second interlocking gasket; and mounting means for mounting the second interlocking gasket in a u-shape around a lower portion of the garage in a cooperative position to the first interlocking gasket, the mounting means comprising a supporting member formed to mount in a cooperative position to the first interlocking gasket on an upper surface of a floor of the garage and an inner surface of a lower portion of the side walls of the garage; wherein: the first and second interlocking gaskets (2, 6) have cooperatively interlocking portions (9, 11); and the first and second interlocking gaskets (2, 6) and mounting means are formed such that when the first interlocking gasket is mounted to an inner surface of a garage door and the second interlocking gasket is mounted in a cooperative position around the garage on the supporting member of the mounting means: the apparatus extends in a U-shape around the lower portion of the garage and the garage door; the second interlocking gasket has a substantially vertical outer face and extends substantially horizontally in an inward direction from the lower portion of the sidewalls of the garage and substantially vertically upwards from the floor of the garage and the garage door; and closing the garage door presses the first interlocking gasket against the second interlocking gasket in a direction of closing to form a plurality of waterproof seals. a u-shaped first interlocking gasket for mounting on an inner surface of the garage door, to extend in a u-shape around a periphery of a lower portion of said inner surface; a u-shaped second interlocking gasket; and mounting means for mounting the second interlocking gasket in a u-shape around a lower portion of the garage in a cooperative position to the first interlocking gasket, the mounting means comprising a supporting member formed to mount in a cooperative position to the first interlocking gasket on an upper surface of a floor of the garage and an inner surface of a lower portion of the side walls of the garage; wherein: the first and second interlocking gaskets (2, 6) have cooperatively interlocking portions (9, 11); and the first and second interlocking gaskets (2, 6) and mounting means are formed such that when the first interlocking gasket is mounted to an inner surface of a garage door and the second interlocking gasket is mounted in a cooperative position around the garage on the supporting member of the mounting means: the apparatus extends in a U-shape around the lower portion of the garage and the garage door; the second interlocking gasket has a substantially vertical outer face and extends substantially horizontally in an inward direction from the lower portion of the sidewalls of the garage and substantially vertically upwards from the floor of the garage and the garage door; and closing the garage door presses the first interlocking gasket against the second interlocking gasket in a direction of closing to form a plurality of waterproof seals. the first and second interlocking gaskets (2, 6) have cooperatively interlocking portions (9, 11); and the first and second interlocking gaskets (2, 6) and mounting means are formed such that when the first interlocking gasket is mounted to an inner surface of a garage door and the second interlocking gasket is mounted in a cooperative position around the garage on the supporting member of the mounting means: the apparatus extends in a U-shape around the lower portion of the garage and the garage door; the second interlocking gasket has a substantially vertical outer face and extends substantially horizontally in an inward direction from the lower portion of the sidewalls of the garage and substantially vertically upwards from the floor of the garage and the garage door; and closing the garage door presses the first interlocking gasket against the second interlocking gasket in a direction of closing to form a plurality of waterproof seals. the apparatus extends in a U-shape around the lower portion of the garage and the garage door; the second interlocking gasket has a substantially vertical outer face and extends substantially horizontally in an inward direction from the lower portion of the sidewalls of the garage and substantially vertically upwards from the floor of the garage and the garage door; and closing the garage door presses the first interlocking gasket against the second interlocking gasket in a direction of closing to form a plurality of waterproof seals.