A stackable riser having a single side wall having a first open end defined by an edge and a second open channel end. A plurality of risers can be stacked on top of one another. The channel end of a riser mates with the first open end of a second riser. The riser includes a plurality of bosses and ribs connected to an interior surface of the sidewall to the edge of the first open end. A channel, on the channel end of one riser is adapted to receive the bosses and ribs of an adjacent riser.